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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Wang Nan <wangnan0@huawei.com>
Cc: a.p.zijlstra@chello.nl, paulus@samba.org0, dsahern@gmail.com,
	jolsa@kernel.org, mingo@redhat.com, lizefan@huawei.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf: top: fix a segfault when kernel map is restricted.
Date: Wed, 29 Apr 2015 19:12:03 -0300	[thread overview]
Message-ID: <20150429221203.GD29633@kernel.org> (raw)
In-Reply-To: <1429918529-225417-1-git-send-email-wangnan0@huawei.com>

Em Fri, Apr 24, 2015 at 11:35:29PM +0000, Wang Nan escreveu:
> Perf top raise a warning if a kernel sample is collected but kernel map
> is restricted. The warning message needs to dereference al.map->dso...
> However, previous perf_event__preprocess_sample() doesn't always
> guarantee al.map != NULL, for example, when kernel map is restricted.
> 
> This patch validates al.map before dereferencing, avoid the segfault.
> 
> Before this patch:
> 
>  $ cat /proc/sys/kernel/kptr_restrict
>  1
>  $ perf top -p  120183

Thanks, applied.

- Arnaldo

      reply	other threads:[~2015-05-04 20:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-24 23:35 [PATCH] perf: top: fix a segfault when kernel map is restricted Wang Nan
2015-04-29 22:12 ` Arnaldo Carvalho de Melo [this message]

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