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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Paul Mackerras <paulus@samba.org>,
	David Miller <davem@davemloft.net>,
	Archs <linux-arch@vger.kernel.org>
Subject: [BUG perf] perf_fetch_caller_regs / rewind_frame_pointer can panic
Date: Thu, 08 Apr 2010 11:57:20 +0200	[thread overview]
Message-ID: <1270720640.2215.43.camel@edumazet-laptop> (raw)
In-Reply-To: <1269568362-13690-6-git-send-regression-fweisbec@gmail.com>

Hello

Current linux-2.6 tree panics on my dev machine

64 bit kernel, 32bit user land
CONFIG_FRAME_POINTER=y

perf timechart record &

Instant crash

Call Trace:
 perf_trace_sched_switch+0xd5/0x120
 schedule+0x6b5/0x860
 retint_careful+0xd/0x21
 
RIP ffffffff81010955 perf_arch_fetch_caller_regs+0x15/0x40
CR2: 00000000d21f1422


rewind_frame_pointer() is probably wrong.

No test performed to check frame is in current stack, or
that (!user_mode_vm(regs))


static inline unsigned long rewind_frame_pointer(int n)
{
	struct stack_frame *frame;

	get_bp(frame);

#ifdef CONFIG_FRAME_POINTER
	while (n--)
		frame = frame->next_frame;
#endif

	return (unsigned long)frame;
}

  parent reply	other threads:[~2010-04-08  9:57 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-26  1:52 [PATCH 0/7] perf updates and fixes Frederic Weisbecker
2010-03-26  1:52 ` Frederic Weisbecker
2010-03-26  1:52 ` [PATCH 4/7] perf: Move perf_arch_fetch_caller_regs into a macro Frederic Weisbecker
2010-03-26  1:52   ` Frederic Weisbecker
2010-03-26  1:52 ` [PATCH 5/7] perf: Make perf_fetch_caller_regs rewind to the first caller only Frederic Weisbecker
2010-03-26  1:52   ` Frederic Weisbecker
2010-04-08  9:57   ` Eric Dumazet [this message]
2010-04-08 10:59     ` [BUG perf] perf_fetch_caller_regs / rewind_frame_pointer can panic Frederic Weisbecker
2010-04-08 12:32     ` [PATCH] perf: Fix unsafe frame rewinding with hot regs fetching Frederic Weisbecker
2010-04-08 13:52       ` Eric Dumazet
2010-04-08 17:31         ` [GIT PULL] perf fix Frederic Weisbecker
2010-04-13 22:51           ` Ingo Molnar
2010-03-26  6:02 ` [PATCH 0/7] perf updates and fixes Paul Mackerras
2010-03-26  7:58   ` Ingo Molnar
2010-03-26 17:38     ` Frederic Weisbecker
2010-03-26 17:45   ` Frederic Weisbecker

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