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2021-08-14mm: slub: fix slub_debug disabling for list of slabsVlastimil Babka1-5/+8
Vijayanand Jitta reports: Consider the scenario where CONFIG_SLUB_DEBUG_ON is set and we would want to disable slub_debug for few slabs. Using boot parameter with slub_debug=-,slab_name syntax doesn't work as expected i.e; only disabling debugging for the specified list of slabs. Instead it disables debugging for all slabs, which is wrong. This patch fixes it by delaying the moment when the global slub_debug flags variable is updated. In case a "slub_debug=-,slab_name" has been passed, the global flags remain as initialized (depending on CONFIG_SLUB_DEBUG_ON enabled or disabled) and are not simply reset to 0. Link: https://lkml.kernel.org/r/8a3d992a-473a-467b-28a0-4ad2ff60ab82@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Vijayanand Jitta <vjitta@codeaurora.org> Reviewed-by: Vijayanand Jitta <vjitta@codeaurora.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-08-14slub: fix kmalloc_pagealloc_invalid_free unit testShakeel Butt1-4/+4
The unit test kmalloc_pagealloc_invalid_free makes sure that for the higher order slub allocation which goes to page allocator, the free is called with the correct address i.e. the virtual address of the head page. Commit f227f0faf63b ("slub: fix unreclaimable slab stat for bulk free") unified the free code paths for page allocator based slub allocations but instead of using the address passed by the caller, it extracted the address from the page. Thus making the unit test kmalloc_pagealloc_invalid_free moot. So, fix this by using the address passed by the caller. Should we fix this? I think yes because dev expect kasan to catch these type of programming bugs. Link: https://lkml.kernel.org/r/20210802180819.1110165-1-shakeelb@google.com Fixes: f227f0faf63b ("slub: fix unreclaimable slab stat for bulk free") Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-08-14kasan, slub: reset tag when printing addressKuan-Ying Lee1-2/+2
The address still includes the tags when it is printed. With hardware tag-based kasan enabled, we will get a false positive KASAN issue when we access metadata. Reset the tag before we access the metadata. Link: https://lkml.kernel.org/r/20210804090957.12393-3-Kuan-Ying.Lee@mediatek.com Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata") Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chinwen Chang <chinwen.chang@mediatek.com> Cc: Nicholas Tang <nicholas.tang@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-30slub: fix unreclaimable slab stat for bulk freeShakeel Butt1-10/+12
SLUB uses page allocator for higher order allocations and update unreclaimable slab stat for such allocations. At the moment, the bulk free for SLUB does not share code with normal free code path for these type of allocations and have missed the stat update. So, fix the stat update by common code. The user visible impact of the bug is the potential of inconsistent unreclaimable slab stat visible through meminfo and vmstat. Link: https://lkml.kernel.org/r/20210728155354.3440560-1-shakeelb@google.com Fixes: 6a486c0ad4dc ("mm, sl[ou]b: improve memory accounting") Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-17Revert "mm/slub: use stackdepot to save stack trace in objects"Linus Torvalds1-49/+30
This reverts commit 788691464c29455346dc613a3b43c2fb9e5757a4. It's not clear why, but it causes unexplained problems in entirely unrelated xfs code. The most likely explanation is some slab corruption, possibly triggered due to CONFIG_SLUB_DEBUG_ON. See [1]. It ends up having a few other problems too, like build errors on arch/arc, and Geert reporting it using much more memory on m68k [3] (it probably does so elsewhere too, but it is probably just more noticeable on m68k). The architecture issues (both build and memory use) are likely just because this change effectively force-enabled STACKDEPOT (along with a very bad default value for the stackdepot hash size). But together with the xfs issue, this all smells like "this commit was not ready" to me. Link: https://lore.kernel.org/linux-xfs/YPE3l82acwgI2OiV@infradead.org/ [1] Link: https://lore.kernel.org/lkml/202107150600.LkGNb4Vb-lkp@intel.com/ [2] Link: https://lore.kernel.org/lkml/CAMuHMdW=eoVzM1Re5FVoEN87nKfiLmM2+Ah7eNu2KXEhCvbZyA@mail.gmail.com/ [3] Reported-by: Christoph Hellwig <hch@infradead.org> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-15mm: move helper to check slub_debug_enabledMarco Elver1-14/+0
Move the helper to check slub_debug_enabled, so that we can confine the use of #ifdef outside slub.c as well. Link: https://lkml.kernel.org/r/20210705103229.8505-2-yee.lee@mediatek.com Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Yee Lee <yee.lee@mediatek.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Chinwen Chang <chinwen.chang@mediatek.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> Cc: Nicholas Tang <nicholas.tang@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08mm/slub: use stackdepot to save stack trace in objectsOliver Glitta1-30/+49
Many stack traces are similar so there are many similar arrays. Stackdepot saves each unique stack only once. Replace field addrs in struct track with depot_stack_handle_t handle. Use stackdepot to save stack trace. The benefits are smaller memory overhead and possibility to aggregate per-cache statistics in the future using the stackdepot handle instead of matching stacks manually. [rdunlap@infradead.org: rename save_stack_trace()] Link: https://lkml.kernel.org/r/20210513051920.29320-1-rdunlap@infradead.org [vbabka@suse.cz: fix lockdep splat] Link: https://lkml.kernel.org/r/20210516195150.26740-1-vbabka@suse.czLink: https://lkml.kernel.org/r/20210414163434.4376-1-glittao@gmail.com Signed-off-by: Oliver Glitta <glittao@gmail.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-04Merge branch 'core-rcu-2021.07.04' of ↵Linus Torvalds1-0/+8
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull RCU updates from Paul McKenney: - Bitmap parsing support for "all" as an alias for all bits - Documentation updates - Miscellaneous fixes, including some that overlap into mm and lockdep - kvfree_rcu() updates - mem_dump_obj() updates, with acks from one of the slab-allocator maintainers - RCU NOCB CPU updates, including limited deoffloading - SRCU updates - Tasks-RCU updates - Torture-test updates * 'core-rcu-2021.07.04' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (78 commits) tasks-rcu: Make show_rcu_tasks_gp_kthreads() be static inline rcu-tasks: Make ksoftirqd provide RCU Tasks quiescent states rcu: Add missing __releases() annotation rcu: Remove obsolete rcu_read_unlock() deadlock commentary rcu: Improve comments describing RCU read-side critical sections rcu: Create an unrcu_pointer() to remove __rcu from a pointer srcu: Early test SRCU polling start rcu: Fix various typos in comments rcu/nocb: Unify timers rcu/nocb: Prepare for fine-grained deferred wakeup rcu/nocb: Only cancel nocb timer if not polling rcu/nocb: Delete bypass_timer upon nocb_gp wakeup rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup rcu/nocb: Allow de-offloading rdp leader rcu/nocb: Directly call __wake_nocb_gp() from bypass timer rcu: Don't penalize priority boosting when there is nothing to boost rcu: Point to documentation of ordering guarantees rcu: Make rcu_gp_cleanup() be noinline for tracing rcu: Restrict RCU_STRICT_GRACE_PERIOD to at most four CPUs rcu: Make show_rcu_gp_kthreads() dump rcu_node structures blocking GP ...
2021-06-29mm/slub: add taint after the errors are printedGeorgi Djakov1-2/+3
When running the kernel with panic_on_taint, the usual slub debug error messages are not being printed when object corruption happens. That's because we panic in add_taint(), which is called before printing the additional information. This is a bit unfortunate as the error messages are actually very useful, especially before a panic. Let's fix this by moving add_taint() after the errors are printed on the console. Link: https://lkml.kernel.org/r/1623860738-146761-1-git-send-email-quic_c_gdjako@quicinc.com Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com> Acked-by: Rafael Aquini <aquini@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29mm: slub: move sysfs slab alloc/free interfaces to debugfsFaiyaz Mohammed1-93/+181
alloc_calls and free_calls implementation in sysfs have two issues, one is PAGE_SIZE limitation of sysfs and other is it does not adhere to "one value per file" rule. To overcome this issues, move the alloc_calls and free_calls implementation to debugfs. Debugfs cache will be created if SLAB_STORE_USER flag is set. Rename the alloc_calls/free_calls to alloc_traces/free_traces, to be inline with what it does. [faiyazm@codeaurora.org: fix the leak of alloc/free traces debugfs interface] Link: https://lkml.kernel.org/r/1624248060-30286-1-git-send-email-faiyazm@codeaurora.org Link: https://lkml.kernel.org/r/1623438200-19361-1-git-send-email-faiyazm@codeaurora.org Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29slub: force on no_hash_pointers when slub_debug is enabledStephen Boyd1-1/+19
Obscuring the pointers that slub shows when debugging makes for some confusing slub debug messages: Padding overwritten. 0x0000000079f0674a-0x000000000d4dce17 Those addresses are hashed for kernel security reasons. If we're trying to be secure with slub_debug on the commandline we have some big problems given that we dump whole chunks of kernel memory to the kernel logs. Let's force on the no_hash_pointers commandline flag when slub_debug is on the commandline. This makes slub debug messages more meaningful and if by chance a kernel address is in some slub debug object dump we will have a better chance of figuring out what went wrong. Note that we don't use %px in the slub code because we want to reduce the number of places that %px is used in the kernel. This also nicely prints a big fat warning at kernel boot if slub_debug is on the commandline so that we know that this kernel shouldn't be used on production systems. [akpm@linux-foundation.org: fix build with CONFIG_SLUB_DEBUG=n] Link: https://lkml.kernel.org/r/20210601182202.3011020-5-swboyd@chromium.org Signed-off-by: Stephen Boyd <swboyd@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Petr Mladek <pmladek@suse.com> Cc: Joe Perches <joe@perches.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29slub: indicate slab_fix() uses printf formatsJoe Perches1-3/+4
Ideally, slab_fix() would be marked with __printf and the format here would not use \n as that's emitted by the slab_fix(). Make these changes. Link: https://lkml.kernel.org/r/20210601182202.3011020-4-swboyd@chromium.org Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Stephen Boyd <swboyd@chromium.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Petr Mladek <pmladek@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29slub: actually use 'message' in restore_bytes()Stephen Boyd1-1/+1
The message argument isn't used here. Let's pass the string to the printk message so that the developer can figure out what's happening, instead of guessing that a redzone is being restored, etc. Link: https://lkml.kernel.org/r/20210601182202.3011020-3-swboyd@chromium.org Signed-off-by: Stephen Boyd <swboyd@chromium.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Petr Mladek <pmladek@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29slub: restore slub_debug=- behaviorStephen Boyd1-0/+2
Petch series "slub: Print non-hashed pointers in slub debugging", v3. I was doing some debugging recently and noticed that my pointers were being hashed while slub_debug was on the kernel commandline. Let's force on the no hash pointer option when slub_debug is on the kernel commandline so that the prints are more meaningful. The first two patches are something else I noticed while looking at the code. The message argument is never used so the debugging messages are not as clear as they could be and the slub_debug=- behavior seems to be busted. Then there's a printf fixup from Joe and the final patch is the one that force disables pointer hashing. This patch (of 4): Passing slub_debug=- on the kernel commandline is supposed to disable slub debugging. This is especially useful with CONFIG_SLUB_DEBUG_ON where the default is to have slub debugging enabled in the build. Due to some code reorganization this behavior was dropped, but the code to make it work mostly stuck around. Restore the previous behavior by disabling the static key when we parse the commandline and see that we're trying to disable slub debugging. Link: https://lkml.kernel.org/r/20210601182202.3011020-1-swboyd@chromium.org Link: https://lkml.kernel.org/r/20210601182202.3011020-2-swboyd@chromium.org Fixes: ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") Signed-off-by: Stephen Boyd <swboyd@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Petr Mladek <pmladek@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29slub: remove resiliency_test() functionOliver Glitta1-64/+0
Function resiliency_test() is hidden behind #ifdef SLUB_RESILIENCY_TEST that is not part of Kconfig, so nobody runs it. This function is replaced with KUnit test for SLUB added by the previous patch "selftests: add a KUnit test for SLUB debugging functionality". Link: https://lkml.kernel.org/r/20210511150734.3492-3-glittao@gmail.com Signed-off-by: Oliver Glitta <glittao@gmail.com> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Oliver Glitta <glittao@gmail.com> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Daniel Latypov <dlatypov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29mm/slub, kunit: add a KUnit test for SLUB debugging functionalityOliver Glitta1-3/+43
SLUB has resiliency_test() function which is hidden behind #ifdef SLUB_RESILIENCY_TEST that is not part of Kconfig, so nobody runs it. KUnit should be a proper replacement for it. Try changing byte in redzone after allocation and changing pointer to next free node, first byte, 50th byte and redzone byte. Check if validation finds errors. There are several differences from the original resiliency test: Tests create own caches with known state instead of corrupting shared kmalloc caches. The corruption of freepointer uses correct offset, the original resiliency test got broken with freepointer changes. Scratch changing random byte test, because it does not have meaning in this form where we need deterministic results. Add new option CONFIG_SLUB_KUNIT_TEST in Kconfig. Tests next_pointer, first_word and clobber_50th_byte do not run with KASAN option on. Because the test deliberately modifies non-allocated objects. Use kunit_resource to count errors in cache and silence bug reports. Count error whenever slab_bug() or slab_fix() is called or when the count of pages is wrong. [glittao@gmail.com: remove unused function test_exit(), from SLUB KUnit test] Link: https://lkml.kernel.org/r/20210512140656.12083-1-glittao@gmail.com [akpm@linux-foundation.org: export kasan_enable/disable_current to modules] Link: https://lkml.kernel.org/r/20210511150734.3492-2-glittao@gmail.com Signed-off-by: Oliver Glitta <glittao@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Daniel Latypov <dlatypov@google.com> Acked-by: Marco Elver <elver@google.com> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-16mm/slub.c: include swab.hAndrew Morton1-0/+1
Fixes build with CONFIG_SLAB_FREELIST_HARDENED=y. Hopefully. But it's the right thing to do anwyay. Fixes: 1ad53d9fa3f61 ("slub: improve bit diffusion for freelist ptr obfuscation") Link: https://bugzilla.kernel.org/show_bug.cgi?id=213417 Reported-by: <vannguye@cisco.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-16mm/slub: actually fix freelist pointer vs redzoningKees Cook1-11/+3
It turns out that SLUB redzoning ("slub_debug=Z") checks from s->object_size rather than from s->inuse (which is normally bumped to make room for the freelist pointer), so a cache created with an object size less than 24 would have the freelist pointer written beyond s->object_size, causing the redzone to be corrupted by the freelist pointer. This was very visible with "slub_debug=ZF": BUG test (Tainted: G B ): Right Redzone overwritten ----------------------------------------------------------------------------- INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200 INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620 Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): 00 00 00 00 00 f6 f4 a5 ........ Redzone (____ptrval____): 40 1d e8 1a aa @.... Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ Adjust the offset to stay within s->object_size. (Note that no caches of in this size range are known to exist in the kernel currently.) Link: https://lkml.kernel.org/r/20210608183955.280836-4-keescook@chromium.org Link: https://lore.kernel.org/linux-mm/20200807160627.GA1420741@elver.google.com/ Link: https://lore.kernel.org/lkml/0f7dd7b2-7496-5e2d-9488-2ec9f8e90441@suse.cz/Fixes: 89b83f282d8b (slub: avoid redzone when choosing freepointer location) Link: https://lore.kernel.org/lkml/CANpmjNOwZ5VpKQn+SYWovTkFB4VsT-RPwyENBmaK0dLcpqStkA@mail.gmail.com Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Marco Elver <elver@google.com> Reported-by: "Lin, Zhenpeng" <zplin@psu.edu> Tested-by: Marco Elver <elver@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-16mm/slub: fix redzoning for small allocationsKees Cook1-3/+5
The redzone area for SLUB exists between s->object_size and s->inuse (which is at least the word-aligned object_size). If a cache were created with an object_size smaller than sizeof(void *), the in-object stored freelist pointer would overwrite the redzone (e.g. with boot param "slub_debug=ZF"): BUG test (Tainted: G B ): Right Redzone overwritten ----------------------------------------------------------------------------- INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200 INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620 Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ Store the freelist pointer out of line when object_size is smaller than sizeof(void *) and redzoning is enabled. Additionally remove the "smaller than sizeof(void *)" check under CONFIG_DEBUG_VM in kmem_cache_sanity_check() as it is now redundant: SLAB and SLOB both handle small sizes. (Note that no caches within this size range are known to exist in the kernel currently.) Link: https://lkml.kernel.org/r/20210608183955.280836-3-keescook@chromium.org Fixes: 81819f0fc828 ("SLUB core") Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Lin, Zhenpeng" <zplin@psu.edu> Cc: Marco Elver <elver@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-16mm/slub: clarify verification reportingKees Cook1-7/+7
Patch series "Actually fix freelist pointer vs redzoning", v4. This fixes redzoning vs the freelist pointer (both for middle-position and very small caches). Both are "theoretical" fixes, in that I see no evidence of such small-sized caches actually be used in the kernel, but that's no reason to let the bugs continue to exist, especially since people doing local development keep tripping over it. :) This patch (of 3): Instead of repeating "Redzone" and "Poison", clarify which sides of those zones got tripped. Additionally fix column alignment in the trailer. Before: BUG test (Tainted: G B ): Redzone overwritten ... Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ After: BUG test (Tainted: G B ): Right Redzone overwritten ... Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ The earlier commits that slowly resulted in the "Before" reporting were: d86bd1bece6f ("mm/slub: support left redzone") ffc79d288000 ("slub: use print_hex_dump") 2492268472e7 ("SLUB: change error reporting format to follow lockdep loosely") Link: https://lkml.kernel.org/r/20210608183955.280836-1-keescook@chromium.org Link: https://lkml.kernel.org/r/20210608183955.280836-2-keescook@chromium.org Link: https://lore.kernel.org/lkml/cfdb11d7-fb8e-e578-c939-f7f5fb69a6bd@suse.cz/ Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Marco Elver <elver@google.com> Cc: "Lin, Zhenpeng" <zplin@psu.edu> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-23kasan: slab: always reset the tag in get_freepointer_safe()Alexander Potapenko1-0/+1
With CONFIG_DEBUG_PAGEALLOC enabled, the kernel should also untag the object pointer, as done in get_freepointer(). Failing to do so reportedly leads to SLUB freelist corruptions that manifest as boot-time crashes. Link: https://lkml.kernel.org/r/20210514072228.534418-1-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Marco Elver <elver@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Elliot Berman <eberman@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-15mm, slub: move slub_debug static key enabling outside slab_mutexVlastimil Babka1-9/+0
Paul E. McKenney reported [1] that commit 1f0723a4c0df ("mm, slub: enable slub_debug static key when creating cache with explicit debug flags") results in the lockdep complaint: ====================================================== WARNING: possible circular locking dependency detected 5.12.0+ #15 Not tainted ------------------------------------------------------ rcu_torture_sta/109 is trying to acquire lock: ffffffff96063cd0 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0x9/0x20 but task is already holding lock: ffffffff96173c28 (slab_mutex){+.+.}-{3:3}, at: kmem_cache_create_usercopy+0x2d/0x250 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (slab_mutex){+.+.}-{3:3}: lock_acquire+0xb9/0x3a0 __mutex_lock+0x8d/0x920 slub_cpu_dead+0x15/0xf0 cpuhp_invoke_callback+0x17a/0x7c0 cpuhp_invoke_callback_range+0x3b/0x80 _cpu_down+0xdf/0x2a0 cpu_down+0x2c/0x50 device_offline+0x82/0xb0 remove_cpu+0x1a/0x30 torture_offline+0x80/0x140 torture_onoff+0x147/0x260 kthread+0x10a/0x140 ret_from_fork+0x22/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: check_prev_add+0x8f/0xbf0 __lock_acquire+0x13f0/0x1d80 lock_acquire+0xb9/0x3a0 cpus_read_lock+0x21/0xa0 static_key_enable+0x9/0x20 __kmem_cache_create+0x38d/0x430 kmem_cache_create_usercopy+0x146/0x250 kmem_cache_create+0xd/0x10 rcu_torture_stats+0x79/0x280 kthread+0x10a/0x140 ret_from_fork+0x22/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(slab_mutex); lock(cpu_hotplug_lock); lock(slab_mutex); lock(cpu_hotplug_lock); *** DEADLOCK *** 1 lock held by rcu_torture_sta/109: #0: ffffffff96173c28 (slab_mutex){+.+.}-{3:3}, at: kmem_cache_create_usercopy+0x2d/0x250 stack backtrace: CPU: 3 PID: 109 Comm: rcu_torture_sta Not tainted 5.12.0+ #15 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: dump_stack+0x6d/0x89 check_noncircular+0xfe/0x110 ? lock_is_held_type+0x98/0x110 check_prev_add+0x8f/0xbf0 __lock_acquire+0x13f0/0x1d80 lock_acquire+0xb9/0x3a0 ? static_key_enable+0x9/0x20 ? mark_held_locks+0x49/0x70 cpus_read_lock+0x21/0xa0 ? static_key_enable+0x9/0x20 static_key_enable+0x9/0x20 __kmem_cache_create+0x38d/0x430 kmem_cache_create_usercopy+0x146/0x250 ? rcu_torture_stats_print+0xd0/0xd0 kmem_cache_create+0xd/0x10 rcu_torture_stats+0x79/0x280 ? rcu_torture_stats_print+0xd0/0xd0 kthread+0x10a/0x140 ? kthread_park+0x80/0x80 ret_from_fork+0x22/0x30 This is because there's one order of locking from the hotplug callbacks: lock(cpu_hotplug_lock); // from hotplug machinery itself lock(slab_mutex); // in e.g. slab_mem_going_offline_callback() And commit 1f0723a4c0df made the reverse sequence possible: lock(slab_mutex); // in kmem_cache_create_usercopy() lock(cpu_hotplug_lock); // kmem_cache_open() -> static_key_enable() The simplest fix is to move static_key_enable() to a place before slab_mutex is taken. That means kmem_cache_create_usercopy() in mm/slab_common.c which is not ideal for SLUB-specific code, but the #ifdef CONFIG_SLUB_DEBUG makes it at least self-contained and obvious. [1] https://lore.kernel.org/lkml/20210502171827.GA3670492@paulmck-ThinkPad-P17-Gen-1/ Link: https://lkml.kernel.org/r/20210504120019.26791-1-vbabka@suse.cz Fixes: 1f0723a4c0df ("mm, slub: enable slub_debug static key when creating cache with explicit debug flags") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-11mm/slub: Add Support for free path information of an objectManinder Singh1-0/+7
This commit adds enables a stack dump for the last free of an object: slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at meminfo_proc_show+0x40/0x4fc [ 20.192078] meminfo_proc_show+0x40/0x4fc [ 20.192263] seq_read_iter+0x18c/0x4c4 [ 20.192430] proc_reg_read_iter+0x84/0xac [ 20.192617] generic_file_splice_read+0xe8/0x17c [ 20.192816] splice_direct_to_actor+0xb8/0x290 [ 20.193008] do_splice_direct+0xa0/0xe0 [ 20.193185] do_sendfile+0x2d0/0x438 [ 20.193345] sys_sendfile64+0x12c/0x140 [ 20.193523] ret_fast_syscall+0x0/0x58 [ 20.193695] 0xbeeacde4 [ 20.193822] Free path: [ 20.193935] meminfo_proc_show+0x5c/0x4fc [ 20.194115] seq_read_iter+0x18c/0x4c4 [ 20.194285] proc_reg_read_iter+0x84/0xac [ 20.194475] generic_file_splice_read+0xe8/0x17c [ 20.194685] splice_direct_to_actor+0xb8/0x290 [ 20.194870] do_splice_direct+0xa0/0xe0 [ 20.195014] do_sendfile+0x2d0/0x438 [ 20.195174] sys_sendfile64+0x12c/0x140 [ 20.195336] ret_fast_syscall+0x0/0x58 [ 20.195491] 0xbeeacde4 Acked-by: Vlastimil Babka <vbabka@suse.cz> Co-developed-by: Vaneet Narang <v.narang@samsung.com> Signed-off-by: Vaneet Narang <v.narang@samsung.com> Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-05-11mm/slub: Fix backtrace of objects to handle redzone adjustmentManinder Singh1-0/+1
This commit fixes commit 8e7f37f2aaa5 ("mm: Add mem_dump_obj() to print source of memory block"). With current code, the backtrace of allocated object is incorrect: / # cat /proc/meminfo [ 14.969843] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at 0x6b6b6b6b [ 14.970635] 0x6b6b6b6b [ 14.970794] 0x6b6b6b6b [ 14.970932] 0x6b6b6b6b [ 14.971077] 0x6b6b6b6b [ 14.971202] 0x6b6b6b6b [ 14.971317] 0x6b6b6b6b [ 14.971423] 0x6b6b6b6b [ 14.971635] 0x6b6b6b6b [ 14.971740] 0x6b6b6b6b [ 14.971871] 0x6b6b6b6b [ 14.972229] 0x6b6b6b6b [ 14.972363] 0x6b6b6b6b [ 14.972505] 0xa56b6b6b [ 14.972631] 0xbbbbbbbb [ 14.972734] 0xc8ab0400 [ 14.972891] meminfo_proc_show+0x40/0x4fc The reason is that the object address was not adjusted for the red zone. With this fix, the backtrace is correct: / # cat /proc/meminfo [ 14.870782] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 128 size 64 allocated at meminfo_proc_show+0x40/0x4f4 [ 14.871817] meminfo_proc_show+0x40/0x4f4 [ 14.872035] seq_read_iter+0x18c/0x4c4 [ 14.872229] proc_reg_read_iter+0x84/0xac [ 14.872433] generic_file_splice_read+0xe8/0x17c [ 14.872621] splice_direct_to_actor+0xb8/0x290 [ 14.872747] do_splice_direct+0xa0/0xe0 [ 14.872896] do_sendfile+0x2d0/0x438 [ 14.873044] sys_sendfile64+0x12c/0x140 [ 14.873229] ret_fast_syscall+0x0/0x58 [ 14.873372] 0xbe861de4 Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Vaneet Narang <v.narang@samsung.com> Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-05-07mm: fix typos in commentsIngo Molnar1-1/+1
Fix ~94 single-word typos in locking code comments, plus a few very obvious grammar mistakes. Link: https://lkml.kernel.org/r/20210322212624.GA1963421@gmail.com Link: https://lore.kernel.org/r/20210322205203.GB1959563@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Cc: Bhaskar Chowdhury <unixbhaskar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan, mm: integrate slab init_on_free with HW_TAGSAndrey Konovalov1-19/+24
This change uses the previously added memory initialization feature of HW_TAGS KASAN routines for slab memory when init_on_free is enabled. With this change, memory initialization memset() is no longer called when both HW_TAGS KASAN and init_on_free are enabled. Instead, memory is initialized in KASAN runtime. For SLUB, the memory initialization memset() is moved into slab_free_hook() that currently directly follows the initialization loop. A new argument is added to slab_free_hook() that indicates whether to initialize the memory or not. To avoid discrepancies with which memory gets initialized that can be caused by future changes, both KASAN hook and initialization memset() are put together and a warning comment is added. Combining setting allocation tags with memory initialization improves HW_TAGS KASAN performance when init_on_free is enabled. Link: https://lkml.kernel.org/r/190fd15c1886654afdec0d19ebebd5ade665b601.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan, mm: integrate slab init_on_alloc with HW_TAGSAndrey Konovalov1-16/+11
This change uses the previously added memory initialization feature of HW_TAGS KASAN routines for slab memory when init_on_alloc is enabled. With this change, memory initialization memset() is no longer called when both HW_TAGS KASAN and init_on_alloc are enabled. Instead, memory is initialized in KASAN runtime. The memory initialization memset() is moved into slab_post_alloc_hook() that currently directly follows the initialization loop. A new argument is added to slab_post_alloc_hook() that indicates whether to initialize the memory or not. To avoid discrepancies with which memory gets initialized that can be caused by future changes, both KASAN hook and initialization memset() are put together and a warning comment is added. Combining setting allocation tags with memory initialization improves HW_TAGS KASAN performance when init_on_alloc is enabled. Link: https://lkml.kernel.org/r/c1292aeb5d519da221ec74a0684a949b027d7720.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30mm/slub.c: trivial typo fixesBhaskar Chowdhury1-4/+4
s/operatios/operations/ s/Mininum/Minimum/ s/mininum/minimum/ ......two different places. Link: https://lkml.kernel.org/r/20210325044940.14516-1-unixbhaskar@gmail.com Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30mm, slub: enable slub_debug static key when creating cache with explicit ↵Vlastimil Babka1-0/+9
debug flags Commit ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") introduced a static key to optimize the case where no debugging is enabled for any cache. The static key is enabled when slub_debug boot parameter is passed, or CONFIG_SLUB_DEBUG_ON enabled. However, some caches might be created with one or more debugging flags explicitly passed to kmem_cache_create(), and the commit missed this. Thus the debugging functionality would not be actually performed for these caches unless the static key gets enabled by boot param or config. This patch fixes it by checking for debugging flags passed to kmem_cache_create() and enabling the static key accordingly. Note such explicit debugging flags should not be used outside of debugging and testing as they will now enable the static key globally. btrfs_init_cachep() creates a cache with SLAB_RED_ZONE but that's a mistake that's being corrected [1]. rcu_torture_stats() creates a cache with SLAB_STORE_USER, but that is a testing module so it's OK and will start working as intended after this patch. Also note that in case of backports to kernels before v5.12 that don't have 59450bbc12be ("mm, slab, slub: stop taking cpu hotplug lock"), static_branch_enable_cpuslocked() should be used. [1] https://lore.kernel.org/linux-btrfs/20210315141824.26099-1-dsterba@suse.com/ Link: https://lkml.kernel.org/r/20210315153415.24404-1-vbabka@suse.cz Fixes: ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Oliver Glitta <glittao@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-28Merge tag 'core-rcu-2021-04-28' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: - Support for "N" as alias for last bit in bitmap parsing library (eg using syntax like "nohz_full=2-N") - kvfree_rcu updates - mm_dump_obj() updates. (One of these is to mm, but was suggested by Andrew Morton.) - RCU callback offloading update - Polling RCU grace-period interfaces - Realtime-related RCU updates - Tasks-RCU updates - Torture-test updates - Torture-test scripting updates - Miscellaneous fixes * tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits) rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu() rcu: Provide polling interfaces for Tiny RCU grace periods torture: Fix kvm.sh --datestamp regex check torture: Consolidate qemu-cmd duration editing into kvm-transform.sh torture: Print proper vmlinux path for kvm-again.sh runs torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment torture: Make kvm-transform.sh update jitter commands torture: Add --duration argument to kvm-again.sh torture: Add kvm-again.sh to rerun a previous torture-test torture: Create a "batches" file for build reuse torture: De-capitalize TORTURE_SUITE torture: Make upper-case-only no-dot no-slash scenario names official torture: Rename SRCU-t and SRCU-u to avoid lowercase characters torture: Remove no-mpstat error message torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs torture: Record jitter start/stop commands torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd torture: Abstract jitter.sh start/stop into scripts rcu: Provide polling interfaces for Tree RCU grace periods ...
2021-04-28Merge tag 'printk-for-5.13' of ↵Linus Torvalds1-6/+7
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Stop synchronizing kernel log buffer readers by logbuf_lock. As a result, the access to the buffer is fully lockless now. Note that printk() itself still uses locks because it tries to flush the messages to the console immediately. Also the per-CPU temporary buffers are still there because they prevent infinite recursion and serialize backtraces from NMI. All this is going to change in the future. - kmsg_dump API rework and cleanup as a side effect of the logbuf_lock removal. - Make bstr_printf() aware that %pf and %pF formats could deference the given pointer. - Show also page flags by %pGp format. - Clarify the documentation for plain pointer printing. - Do not show no_hash_pointers warning multiple times. - Update Senozhatsky email address. - Some clean up. * tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits) lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf() printk: clarify the documentation for plain pointer printing kernel/printk.c: Fixed mundane typos printk: rename vprintk_func to vprintk vsprintf: dump full information of page flags in pGp mm, slub: don't combine pr_err with INFO mm, slub: use pGp to print page flags MAINTAINERS: update Senozhatsky email address lib/vsprintf: do not show no_hash_pointers message multiple times printk: console: remove unnecessary safe buffer usage printk: kmsg_dump: remove _nolock() variants printk: remove logbuf_lock printk: introduce a kmsg_dump iterator printk: kmsg_dumper: remove @active field printk: add syslog_lock printk: use atomic64_t for devkmsg_user.seq printk: use seqcount_latch for clear_seq printk: introduce CONSOLE_LOG_MAX printk: consolidate kmsg_dump_get_buffer/syslog_print_all code printk: refactor kmsg_dump_get_buffer() ...
2021-04-11Merge branch 'for-mingo-rcu' of ↵Ingo Molnar1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU changes from Paul E. McKenney: - Bitmap support for "N" as alias for last bit - kvfree_rcu updates - mm_dump_obj() updates. (One of these is to mm, but was suggested by Andrew Morton.) - RCU callback offloading update - Polling RCU grace-period interfaces - Realtime-related RCU updates - Tasks-RCU updates - Torture-test updates - Torture-test scripting updates - Miscellaneous fixes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-03-19mm, slub: don't combine pr_err with INFOYafang Shao1-5/+5
It is strange to combine "pr_err" with "INFO", so let's remove the prefix completely. This patch is motivated by David's comment[1]. - before the patch [ 8846.517809] INFO: Slab 0x00000000f42a2c60 objects=33 used=3 fp=0x0000000060d32ca8 flags=0x17ffffc0010200(slab|head) - after the patch [ 6343.396602] Slab 0x000000004382e02b objects=33 used=3 fp=0x000000009ae06ffc flags=0x17ffffc0010200(slab|head) [1] https://lore.kernel.org/linux-mm/b9c0f2b6-e9b0-0c36-ebdd-2bc684c5a762@redhat.com/#t Suggested-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Matthew Wilcox <willy@infradead.org> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210319101246.73513-3-laoar.shao@gmail.com
2021-03-19mm, slub: use pGp to print page flagsYafang Shao1-2/+3
As pGp has been already introduced in printk, we'd better use it to make the output human readable. Before this change, the output is, [ 6155.716018] INFO: Slab 0x000000004027dd4f objects=33 used=3 fp=0x000000008cd1579c flags=0x17ffffc0010200 While after this change, the output is, [ 8846.517809] INFO: Slab 0x00000000f42a2c60 objects=33 used=3 fp=0x0000000060d32ca8 flags=0x17ffffc0010200(slab|head) Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210319101246.73513-2-laoar.shao@gmail.com
2021-03-10Revert "mm, slub: consider rest of partial list if acquire_slab() fails"Linus Torvalds1-1/+1
This reverts commit 8ff60eb052eeba95cfb3efe16b08c9199f8121cf. The kernel test robot reports a huge performance regression due to the commit, and the reason seems fairly straightforward: when there is contention on the page list (which is what causes acquire_slab() to fail), we do _not_ want to just loop and try again, because that will transfer the contention to the 'n->list_lock' spinlock we hold, and just make things even worse. This is admittedly likely a problem only on big machines - the kernel test robot report comes from a 96-thread dual socket Intel Xeon Gold 6252 setup, but the regression there really is quite noticeable: -47.9% regression of stress-ng.rawpkt.ops_per_sec and the commit that was marked as being fixed (7ced37197196: "slub: Acquire_slab() avoid loop") actually did the loop exit early very intentionally (the hint being that "avoid loop" part of that commit message), exactly to avoid this issue. The correct thing to do may be to pick some kind of reasonable middle ground: instead of breaking out of the loop on the very first sign of contention, or trying over and over and over again, the right thing may be to re-try _once_, and then give up on the second failure (or pick your favorite value for "once"..). Reported-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/lkml/20210301080404.GF12822@xsang-OptiPlex-9020/ Cc: Jann Horn <jannh@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-03-09mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernelsPaul E. McKenney1-0/+2
The mem_dump_obj() functionality adds a few hundred bytes, which is a small price to pay. Except on kernels built with CONFIG_PRINTK=n, in which mem_dump_obj() messages will be suppressed. This commit therefore makes mem_dump_obj() be a static inline empty function on kernels built with CONFIG_PRINTK=n and excludes all of its support functions as well. This avoids kernel bloat on systems that cannot use mem_dump_obj(). Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <linux-mm@kvack.org> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-02-26kasan, mm: optimize kmalloc poisoningAndrey Konovalov1-2/+1
For allocations from kmalloc caches, kasan_kmalloc() always follows kasan_slab_alloc(). Currenly, both of them unpoison the whole object, which is unnecessary. This patch provides separate implementations for both annotations: kasan_slab_alloc() unpoisons the whole object, and kasan_kmalloc() only poisons the redzone. For generic KASAN, the redzone start might not be aligned to KASAN_GRANULE_SIZE. Therefore, the poisoning is split in two parts: kasan_poison_last_granule() poisons the unaligned part, and then kasan_poison() poisons the rest. This patch also clarifies alignment guarantees of each of the poisoning functions and drops the unnecessary round_up() call for redzone_end. With this change, the early SLUB cache annotation needs to be changed to kasan_slab_alloc(), as kasan_kmalloc() doesn't unpoison objects now. The number of poisoned bytes for objects in this cache stays the same, as kmem_cache_node->object_size is equal to sizeof(struct kmem_cache_node). Link: https://lkml.kernel.org/r/7e3961cb52be380bc412860332063f5f7ce10d13.1612546384.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26mm, kfence: insert KFENCE hooks for SLUBAlexander Potapenko1-14/+46
Inserts KFENCE hooks into the SLUB allocator. To pass the originally requested size to KFENCE, add an argument 'orig_size' to slab_alloc*(). The additional argument is required to preserve the requested original size for kmalloc() allocations, which uses size classes (e.g. an allocation of 272 bytes will return an object of size 512). Therefore, kmem_cache::size does not represent the kmalloc-caller's requested size, and we must introduce the argument 'orig_size' to propagate the originally requested size to KFENCE. Without the originally requested size, we would not be able to detect out-of-bounds accesses for objects placed at the end of a KFENCE object page if that object is not equal to the kmalloc-size class it was bucketed into. When KFENCE is disabled, there is no additional overhead, since slab_alloc*() functions are __always_inline. Link: https://lkml.kernel.org/r/20201103175841.3495947-6-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Jann Horn <jannh@google.com> Co-developed-by: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hillf Danton <hdanton@sina.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joern Engel <joern@purestorage.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: SeongJae Park <sjpark@amazon.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25kasan: move _RET_IP_ to inline wrappersAndrey Konovalov1-2/+2
Generic mm functions that call KASAN annotations that might report a bug pass _RET_IP_ to them as an argument. This allows KASAN to include the name of the function that called the mm function in its report's header. Now that KASAN has inline wrappers for all of its annotations, move _RET_IP_ to those wrappers to simplify annotation call sites. Link: https://linux-review.googlesource.com/id/I8fb3c06d49671305ee184175a39591bc26647a67 Link: https://lkml.kernel.org/r/5c1490eddf20b436b8c4eeea83fce47687d5e4a4.1610733117.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm: memcontrol: fix slub memory accountingMuchun Song1-4/+4
SLUB currently account kmalloc() and kmalloc_node() allocations larger than order-1 page per-node. But it forget to update the per-memcg vmstats. So it can lead to inaccurate statistics of "slab_unreclaimable" which is from memory.stat. Fix it by using mod_lruvec_page_state instead of mod_node_page_state. Link: https://lkml.kernel.org/r/20210223092423.42420-1-songmuchun@bytedance.com Fixes: 6a486c0ad4dc ("mm, sl[ou]b: improve memory accounting") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm: memcg/slab: pre-allocate obj_cgroups for slab caches with SLAB_ACCOUNTRoman Gushchin1-1/+1
In general it's unknown in advance if a slab page will contain accounted objects or not. In order to avoid memory waste, an obj_cgroup vector is allocated dynamically when a need to account of a new object arises. Such approach is memory efficient, but requires an expensive cmpxchg() to set up the memcg/objcgs pointer, because an allocation can race with a different allocation on another cpu. But in some common cases it's known for sure that a slab page will contain accounted objects: if the page belongs to a slab cache with a SLAB_ACCOUNT flag set. It includes such popular objects like vm_area_struct, anon_vma, task_struct, etc. In such cases we can pre-allocate the objcgs vector and simple assign it to the page without any atomic operations, because at this early stage the page is not visible to anyone else. A very simplistic benchmark (allocating 10000000 64-bytes objects in a row) shows ~15% win. In the real life it seems that most workloads are not very sensitive to the speed of (accounted) slab allocations. [guro@fb.com: open-code set_page_objcgs() and add some comments, by Johannes] Link: https://lkml.kernel.org/r/20201113001926.GA2934489@carbon.dhcp.thefacebook.com [akpm@linux-foundation.org: fix it for mm-slub-call-account_slab_page-after-slab-page-initialization-fix.patch] Link: https://lkml.kernel.org/r/20201110195753.530157-2-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm/slub: minor coding style tweaksZhiyuan Dai1-1/+1
Add whitespace to fix coding style issues, improve code reading. Link: https://lkml.kernel.org/r/1612847403-5594-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm, slub: remove slub_memcg_sysfs boot param and CONFIG_SLUB_MEMCG_SYSFS_ONVlastimil Babka1-16/+0
The boot param and config determine the value of memcg_sysfs_enabled, which is unused since commit 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations") as there are no per-memcg kmem caches anymore. Link: https://lkml.kernel.org/r/20210127124745.7928-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm, slub: splice cpu and page freelists in deactivate_slab()Vlastimil Babka1-35/+24
In deactivate_slab() we currently move all but one objects on the cpu freelist to the page freelist one by one using the costly cmpxchg_double() operation. Then we unfreeze the page while moving the last object on page freelist, with a final cmpxchg_double(). This can be optimized to avoid the cmpxchg_double() per object. Just count the objects on cpu freelist (to adjust page->inuse properly) and also remember the last object in the chain. Then splice page->freelist to the last object and effectively add the whole cpu freelist to page->freelist while unfreezing the page, with a single cmpxchg_double(). Link: https://lkml.kernel.org/r/20210115183543.15097-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Jann Horn <jannh@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm, slab, slub: stop taking memory hotplug lockVlastimil Babka1-3/+25
Since commit 03afc0e25f7f ("slab: get_online_mems for kmem_cache_{create,destroy,shrink}") we are taking memory hotplug lock for SLAB and SLUB when creating, destroying or shrinking a cache. It is quite a heavy lock and it's best to avoid it if possible, as we had several issues with lockdep complaining about ordering in the past, see e.g. e4f8e513c3d3 ("mm/slub: fix a deadlock in show_slab_objects()"). The problem scenario in 03afc0e25f7f (solved by the memory hotplug lock) can be summarized as follows: while there's slab_mutex synchronizing new kmem cache creation and SLUB's MEM_GOING_ONLINE callback slab_mem_going_online_callback(), we may miss creation of kmem_cache_node for the hotplugged node in the new kmem cache, because the hotplug callback doesn't yet see the new cache, and cache creation in init_kmem_cache_nodes() only inits kmem_cache_node for nodes in the N_NORMAL_MEMORY nodemask, which however may not yet include the new node, as that happens only later after the MEM_GOING_ONLINE callback. Instead of using get/put_online_mems(), the problem can be solved by SLUB maintaining its own nodemask of nodes for which it has allocated the per-node kmem_cache_node structures. This nodemask would generally mirror the N_NORMAL_MEMORY nodemask, but would be updated only in under SLUB's control in its memory hotplug callbacks under the slab_mutex. This patch adds such nodemask and its handling. Commit 03afc0e25f7f mentiones "issues like [the one above]", but there don't appear to be further issues. All the paths (shared for SLAB and SLUB) taking the memory hotplug locks are also taking the slab_mutex, except kmem_cache_shrink() where 03afc0e25f7f replaced slab_mutex with get/put_online_mems(). We however cannot simply restore slab_mutex in kmem_cache_shrink(), as SLUB can enters the function from a write to sysfs 'shrink' file, thus holding kernfs lock, and in kmem_cache_create() the kernfs lock is nested within slab_mutex. But on closer inspection we don't actually need to protect kmem_cache_shrink() from hotplug callbacks: While SLUB's __kmem_cache_shrink() does for_each_kmem_cache_node(), missing a new node added in parallel hotplug is not fatal, and parallel hotremove does not free kmem_cache_node's anymore after the previous patch, so use-after free cannot happen. The per-node shrinking itself is protected by n->list_lock. Same is true for SLAB, and SLOB is no-op. SLAB also doesn't need the memory hotplug locking, which it only gained by 03afc0e25f7f through the shared paths in slab_common.c. Its memory hotplug callbacks are also protected by slab_mutex against races with these paths. The problem of SLUB relying on N_NORMAL_MEMORY doesn't apply to SLAB, as its setup_kmem_cache_nodes relies on N_ONLINE, and the new node is already set there during the MEM_GOING_ONLINE callback, so no special care is needed for SLAB. As such, this patch removes all get/put_online_mems() usage by the slab subsystem. Link: https://lkml.kernel.org/r/20210113131634.3671-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Qian Cai <cai@redhat.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm, slub: stop freeing kmem_cache_node structures on node offlineVlastimil Babka1-17/+11
Patch series "mm, slab, slub: remove cpu and memory hotplug locks". Some related work caused me to look at how we use get/put_mems_online() and get/put_online_cpus() during kmem cache creation/descruction/shrinking, and realize that it should be actually safe to remove all of that with rather small effort (as e.g. Michal Hocko suspected in some of the past discussions already). This has the benefit to avoid rather heavy locks that have caused locking order issues already in the past. So this is the result, Patches 2 and 3 remove memory hotplug and cpu hotplug locking, respectively. Patch 1 is due to realization that in fact some races exist despite the locks (even if not removed), but the most sane solution is not to introduce more of them, but rather accept some wasted memory in scenarios that should be rare anyway (full memory hot remove), as we do the same in other contexts already. This patch (of 3): Commit e4f8e513c3d3 ("mm/slub: fix a deadlock in show_slab_objects()") has fixed a problematic locking order by removing the memory hotplug lock get/put_online_mems() from show_slab_objects(). During the discussion, it was argued [1] that this is OK, because existing slabs on the node would prevent a hotremove to proceed. That's true, but per-node kmem_cache_node structures are not necessarily allocated on the same node and may exist even without actual slab pages on the same node. Any path that uses get_node() directly or via for_each_kmem_cache_node() (such as show_slab_objects()) can race with freeing of kmem_cache_node even with the !NULL check, resulting in use-after-free. To that end, commit e4f8e513c3d3 argues in a comment that: * We don't really need mem_hotplug_lock (to hold off * slab_mem_going_offline_callback) here because slab's memory hot * unplug code doesn't destroy the kmem_cache->node[] data. While it's true that slab_mem_going_offline_callback() doesn't free the kmem_cache_node, the later callback slab_mem_offline_callback() actually does, so the race and use-after-free exists. Not just for show_slab_objects() after commit e4f8e513c3d3, but also many other places that are not under slab_mutex. And adding slab_mutex locking or other synchronization to SLUB paths such as get_any_partial() would be bad for performance and error-prone. The easiest solution is therefore to make the abovementioned comment true and stop freeing the kmem_cache_node structures, accepting some wasted memory in the full memory node removal scenario. Analogically we also don't free hotremoved pgdat as mentioned in [1], nor the similar per-node structures in SLAB. Importantly this approach will not block the hotremove, as generally such nodes should be movable in order to succeed hotremove in the first place, and thus the GFP_KERNEL allocated kmem_cache_node will come from elsewhere. [1] https://lore.kernel.org/linux-mm/20190924151147.GB23050@dhcp22.suse.cz/ Link: https://lkml.kernel.org/r/20210113131634.3671-1-vbabka@suse.cz Link: https://lkml.kernel.org/r/20210113131634.3671-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Qian Cai <cai@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm/slub: disable user tracing for kmemleak caches by defaultJohannes Berg1-1/+10
If kmemleak is enabled, it uses a kmem cache for its own objects. These objects are used to hold information kmemleak uses, including a stack trace. If slub_debug is also turned on, each of them has *another* stack trace, so the overhead adds up, and on my tests (on ARCH=um, admittedly) 2/3rds of the allocations end up being doing the stack tracing. Turn off SLAB_STORE_USER if SLAB_NOLEAKTRACE was given, to avoid storing the essentially same data twice. Link: https://lkml.kernel.org/r/20210113215114.d94efa13ba30.I117b6764e725b3192318bbcf4269b13b709539ae@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm/sl?b.c: remove ctor argument from kmem_cache_flagsNikolay Borisov1-6/+3
This argument hasn't been used since e153362a50a3 ("slub: Remove objsize check in kmem_cache_flags()") so simply remove it. Link: https://lkml.kernel.org/r/20210126095733.974665-1-nborisov@suse.com Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-25mm, tracing: record slab name for kmem_cache_free()Jacob Wen1-1/+1
Currently, a trace record generated by the RCU core is as below. ... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=00000000f3b49a66 It doesn't tell us what the RCU core has freed. This patch adds the slab name to trace_kmem_cache_free(). The new format is as follows. ... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=0000000037f79c8d name=dentry ... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=00000000f78cb7b5 name=sock_inode_cache ... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=0000000018768985 name=pool_workqueue ... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=000000006a6cb484 name=radix_tree_node We can use it to understand what the RCU core is going to free. For example, some users maybe interested in when the RCU core starts freeing reclaimable slabs like dentry to reduce memory pressure. Link: https://lkml.kernel.org/r/20201216072804.8838-1-jian.w.wen@oracle.com Signed-off-by: Jacob Wen <jian.w.wen@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-12Merge branch 'for-mingo-rcu' of ↵Ingo Molnar1-0/+40
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Documentation updates. - Miscellaneous fixes. - kfree_rcu() updates: Addition of mem_dump_obj() to provide allocator return addresses to more easily locate bugs. This has a couple of RCU-related commits, but is mostly MM. Was pulled in with akpm's agreement. - Per-callback-batch tracking of numbers of callbacks, which enables better debugging information and smarter reactions to large numbers of callbacks. - The first round of changes to allow CPUs to be runtime switched from and to callback-offloaded state. - CONFIG_PREEMPT_RT-related changes. - RCU CPU stall warning updates. - Addition of polling grace-period APIs for SRCU. - Torture-test and torture-test scripting updates, including a "torture everything" script that runs rcutorture, locktorture, scftorture, rcuscale, and refscale. Plus does an allmodconfig build. Signed-off-by: Ingo Molnar <mingo@kernel.org>
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