* [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y
@ 2017-11-30 12:35 Andrey Ryabinin
2017-11-30 12:38 ` Dmitry Vyukov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Andrey Ryabinin @ 2017-11-30 12:35 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86
Cc: linux-kernel, Josh Poimboeuf, Alexander Potapenko, Dmitry Vyukov,
xiaolong.ye, fengguang.wu, Andrey Ryabinin
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 STACKDEPOT=n dependency to UNWINDER_GUESS to avoid the problem.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
---
arch/x86/Kconfig.debug | 1 +
1 file changed, 1 insertion(+)
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
--
2.13.6
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y
2017-11-30 12:35 [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y Andrey Ryabinin
@ 2017-11-30 12:38 ` Dmitry Vyukov
2017-11-30 13:57 ` Josh Poimboeuf
2017-12-12 10:58 ` [tip:x86/urgent] x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y tip-bot for Andrey Ryabinin
2 siblings, 0 replies; 4+ messages in thread
From: Dmitry Vyukov @ 2017-11-30 12:38 UTC (permalink / raw)
To: Andrey Ryabinin
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
the arch/x86 maintainers, LKML, Josh Poimboeuf,
Alexander Potapenko, kernel test robot, Fengguang Wu
On Thu, Nov 30, 2017 at 1:35 PM, Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
> 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 STACKDEPOT=n dependency to UNWINDER_GUESS to avoid the problem.
>
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Reported-by: kernel test robot <xiaolong.ye@intel.com>
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> ---
> arch/x86/Kconfig.debug | 1 +
> 1 file changed, 1 insertion(+)
>
> 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
> --
> 2.13.6
>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y
2017-11-30 12:35 [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y Andrey Ryabinin
2017-11-30 12:38 ` Dmitry Vyukov
@ 2017-11-30 13:57 ` Josh Poimboeuf
2017-12-12 10:58 ` [tip:x86/urgent] x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y tip-bot for Andrey Ryabinin
2 siblings, 0 replies; 4+ messages in thread
From: Josh Poimboeuf @ 2017-11-30 13:57 UTC (permalink / raw)
To: Andrey Ryabinin
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, linux-kernel,
Alexander Potapenko, Dmitry Vyukov, xiaolong.ye, fengguang.wu
On Thu, Nov 30, 2017 at 03:35:54PM +0300, Andrey Ryabinin wrote:
> 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 STACKDEPOT=n dependency to UNWINDER_GUESS to avoid the problem.
>
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Reported-by: kernel test robot <xiaolong.ye@intel.com>
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip:x86/urgent] x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y
2017-11-30 12:35 [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y Andrey Ryabinin
2017-11-30 12:38 ` Dmitry Vyukov
2017-11-30 13:57 ` Josh Poimboeuf
@ 2017-12-12 10:58 ` tip-bot for Andrey Ryabinin
2 siblings, 0 replies; 4+ messages in thread
From: tip-bot for Andrey Ryabinin @ 2017-12-12 10:58 UTC (permalink / raw)
To: linux-tip-commits
Cc: hpa, peterz, linux-kernel, aryabinin, xiaolong.ye, torvalds,
dvyukov, tglx, fengguang.wu, glider, jpoimboe, mingo
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-12-12 11:02 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-11-30 12:35 [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y Andrey Ryabinin
2017-11-30 12:38 ` Dmitry Vyukov
2017-11-30 13:57 ` Josh Poimboeuf
2017-12-12 10:58 ` [tip:x86/urgent] x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y tip-bot for Andrey Ryabinin
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