From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, mingo@redhat.com,
kim.phillips@amd.com, Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH 1/2] x86/unwind/orc: recheck address range after stack info was updated
Date: Tue, 12 Apr 2022 12:08:37 +0200 [thread overview]
Message-ID: <YlVPpVC8chepOdzJ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1649749204-186363-1-git-send-email-dmtrmonakhov@yandex-team.ru>
On Tue, Apr 12, 2022 at 10:40:03AM +0300, Dmitry Monakhov wrote:
> get_stack_info() detects stack type only by begin address, so we must
> check that address range in question is fully covered by detected stack
>
> Otherwise following crash is possible:
> -> unwind_next_frame
> case ORC_TYPE_REGS:
> if (!deref_stack_regs(state, sp, &state->ip, &state->sp))
> -> deref_stack_regs
> -> stack_access_ok <- here addr is inside stack range, but addr+len-1 is not, but we still exit with success
> *ip = READ_ONCE_NOCHECK(regs->ip); <- Here we hit stack guard fault
> OOPS LOG:
> <0>[ 1941.845743] BUG: stack guard page was hit at 000000000dd984a2 (stack is 00000000d1caafca..00000000613712f0)
> <4>[ 1941.845751] get_perf_callchain+0x10d/0x280
> <4>[ 1941.845751] perf_callchain+0x6e/0x80
> <4>[ 1941.845752] perf_prepare_sample+0x87/0x540
> <4>[ 1941.845752] perf_event_output_forward+0x31/0x90
> <4>[ 1941.845753] __perf_event_overflow+0x5a/0xf0
> <4>[ 1941.845754] perf_ibs_handle_irq+0x340/0x5b0
> <4>[ 1941.845757] perf_ibs_nmi_handler+0x34/0x60
> <4>[ 1941.845757] nmi_handle+0x79/0x190
Urgh, this is another instance of trying to unwind an IP that no longer
matches the stack.
Fixing the unwinder bug is good, but arguable we should also fix this
IBS stuff, see 6cbc304f2f36 ("perf/x86/intel: Fix unwind errors from PEBS entries (mk-II)")
next prev parent reply other threads:[~2022-04-12 11:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-12 7:40 [PATCH 1/2] x86/unwind/orc: recheck address range after stack info was updated Dmitry Monakhov
2022-04-12 7:40 ` [PATCH 2/2] x86/unwind/orc: Fix address check size for deref_stack_iret_regs Dmitry Monakhov
2022-04-12 10:01 ` Peter Zijlstra
2022-04-12 10:57 ` Dmitry Monakhov
2022-04-12 10:08 ` Peter Zijlstra [this message]
2022-04-16 0:49 ` [PATCH 1/2] x86/unwind/orc: recheck address range after stack info was updated Josh Poimboeuf
2022-04-29 5:14 ` [PATCH] perf/amd/ibs: Use interrupt regs ip for stack unwinding Ravi Bangoria
2022-04-29 20:28 ` [tip: perf/core] " tip-bot2 for Ravi Bangoria
2022-05-02 6:07 ` [PATCH] " Namhyung Kim
2022-05-04 9:23 ` [tip: perf/core] " tip-bot2 for Ravi Bangoria
2022-05-10 9:11 ` tip-bot2 for Ravi Bangoria
2022-04-12 10:11 ` [PATCH 1/2] x86/unwind/orc: recheck address range after stack info was updated Peter Zijlstra
2022-04-14 15:18 ` Josh Poimboeuf
2022-04-16 0:46 ` Josh Poimboeuf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YlVPpVC8chepOdzJ@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=dmtrmonakhov@yandex-team.ru \
--cc=jpoimboe@redhat.com \
--cc=kim.phillips@amd.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.