From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
xiaolong.ye@intel.com, fengguang.wu@intel.com,
Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y
Date: Thu, 30 Nov 2017 15:35:54 +0300 [thread overview]
Message-ID: <20171130123554.4330-1-aryabinin@virtuozzo.com> (raw)
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
next reply other threads:[~2017-11-30 12:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 12:35 Andrey Ryabinin [this message]
2017-11-30 12:38 ` [PATCH] x86/unwind_guess: Prevent using UNWINDER_GUESS=y with STACKDEPOT=y 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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