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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2017-11-30 15:35:54 +0300
committerIngo Molnar <mingo@kernel.org>2017-12-11 21:07:07 +0300
commit0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe (patch)
treee3ed50888a5c91fb5d6b0e23006c916c31018968 /arch
parentf79ce87fa49da778a1ad54c7d3c6755e13cf8489 (diff)
downloadlinux-0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe.tar.xz
x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y
Stackdepot doesn't work well with CONFIG_UNWINDER_GUESS=y. The 'guess' unwinder generate awfully large and inaccurate stacktraces, thus stackdepot can't deduplicate stacktraces because they all look like unique. Eventually stackdepot reaches its capacity limit: WARNING: CPU: 0 PID: 545 at lib/stackdepot.c:119 depot_save_stack+0x28e/0x550 Call Trace: ? kasan_kmalloc+0x144/0x160 ? depot_save_stack+0x1f5/0x550 ? do_raw_spin_unlock+0xda/0xf0 ? preempt_count_sub+0x13/0xc0 <...90 lines...> ? do_raw_spin_unlock+0xda/0xf0 Add a STACKDEPOT=n dependency to UNWINDER_GUESS to avoid the problem. Reported-by: kernel test robot <xiaolong.ye@intel.com> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Alexander Potapenko <glider@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20171130123554.4330-1-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig.debug1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 6293a8768a91..672441c008c7 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -400,6 +400,7 @@ config UNWINDER_FRAME_POINTER
config UNWINDER_GUESS
bool "Guess unwinder"
depends on EXPERT
+ depends on !STACKDEPOT
---help---
This option enables the "guess" unwinder for unwinding kernel stack
traces. It scans the stack and reports every kernel text address it