Messages in this thread Patch in this message | | | Date | Tue, 12 Dec 2017 02:58:03 -0800 | From | tip-bot for Andrey Ryabinin <> | Subject | [tip:x86/urgent] x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y |
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Commit-ID: 0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe Gitweb: https://git.kernel.org/tip/0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe Author: Andrey Ryabinin <aryabinin@virtuozzo.com> AuthorDate: Thu, 30 Nov 2017 15:35:54 +0300 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 11 Dec 2017 19:07:07 +0100
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> --- arch/x86/Kconfig.debug | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 6293a87..672441c 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
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