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authorLinus Torvalds <torvalds@linux-foundation.org>2024-01-30 04:12:16 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2024-01-30 04:12:16 +0300
commit6f3d7d5cedbad7a859bb34161a2807c58e6cdda8 (patch)
treef3b65442c181a4c2d52a070fcfa22e70ef9b5711 /arch
parent41bccc98fb7931d63d03f326a746ac4d429c1dd3 (diff)
parent96204e15310c218fd9355bdcacd02fed1d18070e (diff)
downloadlinux-6f3d7d5cedbad7a859bb34161a2807c58e6cdda8.tar.xz
Merge tag 'mm-hotfixes-stable-2024-01-28-23-21' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton: "22 hotfixes. 11 are cc:stable and the remainder address post-6.7 issues or aren't considered appropriate for backporting" * tag 'mm-hotfixes-stable-2024-01-28-23-21' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits) mm: thp_get_unmapped_area must honour topdown preference mm: huge_memory: don't force huge page alignment on 32 bit userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb selftests/mm: ksm_tests should only MADV_HUGEPAGE valid memory scs: add CONFIG_MMU dependency for vfree_atomic() mm/memory: fix folio_set_dirty() vs. folio_mark_dirty() in zap_pte_range() mm/huge_memory: fix folio_set_dirty() vs. folio_mark_dirty() selftests/mm: Update va_high_addr_switch.sh to check CPU for la57 flag selftests: mm: fix map_hugetlb failure on 64K page size systems MAINTAINERS: supplement of zswap maintainers update stackdepot: make fast paths lock-less again stackdepot: add stats counters exported via debugfs mm, kmsan: fix infinite recursion due to RCU critical section mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again selftests/mm: switch to bash from sh MAINTAINERS: add man-pages git trees mm: memcontrol: don't throttle dying tasks on memory.high mm: mmap: map MAP_STACK to VM_NOHUGEPAGE uprobes: use pagesize-aligned virtual address when replacing pages selftests/mm: mremap_test: fix build warning ...
Diffstat (limited to 'arch')
-rw-r--r--arch/Kconfig1
-rw-r--r--arch/x86/include/asm/kmsan.h17
2 files changed, 17 insertions, 1 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index c91917b50873..a5af0edd3eb8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -673,6 +673,7 @@ config SHADOW_CALL_STACK
bool "Shadow Call Stack"
depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
+ depends on MMU
help
This option enables the compiler's Shadow Call Stack, which
uses a shadow stack to protect function return addresses from
diff --git a/arch/x86/include/asm/kmsan.h b/arch/x86/include/asm/kmsan.h
index 8fa6ac0e2d76..d91b37f5b4bb 100644
--- a/arch/x86/include/asm/kmsan.h
+++ b/arch/x86/include/asm/kmsan.h
@@ -64,6 +64,7 @@ static inline bool kmsan_virt_addr_valid(void *addr)
{
unsigned long x = (unsigned long)addr;
unsigned long y = x - __START_KERNEL_map;
+ bool ret;
/* use the carry flag to determine if x was < __START_KERNEL_map */
if (unlikely(x > y)) {
@@ -79,7 +80,21 @@ static inline bool kmsan_virt_addr_valid(void *addr)
return false;
}
- return pfn_valid(x >> PAGE_SHIFT);
+ /*
+ * pfn_valid() relies on RCU, and may call into the scheduler on exiting
+ * the critical section. However, this would result in recursion with
+ * KMSAN. Therefore, disable preemption here, and re-enable preemption
+ * below while suppressing reschedules to avoid recursion.
+ *
+ * Note, this sacrifices occasionally breaking scheduling guarantees.
+ * Although, a kernel compiled with KMSAN has already given up on any
+ * performance guarantees due to being heavily instrumented.
+ */
+ preempt_disable();
+ ret = pfn_valid(x >> PAGE_SHIFT);
+ preempt_enable_no_resched();
+
+ return ret;
}
#endif /* !MODULE */