From: Greg KH <gregkh@linuxfoundation.org>
To: Krister Johansen <kjlx@templeofstupid.com>
Cc: stable@vger.kernel.org, acme@redhat.com, fweisbec@gmail.com,
mhiramat@kernel.org, namhyung@kernel.org
Subject: Re: [PATCH stable-4.9] perf callchain: Reference count maps
Date: Thu, 9 Mar 2017 19:45:23 +0100 [thread overview]
Message-ID: <20170309184523.GA16414@kroah.com> (raw)
In-Reply-To: <20170309175720.GA3408@templeofstupid.com>
On Thu, Mar 09, 2017 at 09:57:20AM -0800, Krister Johansen wrote:
> commit aa33b9b9a2ebb00d33c83a5312d4fbf2d5aeba36 upstream.
>
> If dso__load_kcore frees all of the existing maps, but one has already
> been attached to a callchain cursor node, then we can get a SIGSEGV in
> any function that happens to try to use this invalid cursor. Use the
> existing map refcount mechanism to forestall cleanup of a map until the
> cursor iterates past the node.
>
> Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: stable@kernel.org
> Fixes: 84c2cafa2889 ("perf tools: Reference count struct map")
> Link: http://lkml.kernel.org/r/20170106062331.GB2707@templeofstupid.com
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/util/callchain.c | 11 +++++++++--
> tools/perf/util/callchain.h | 6 ++++++
> tools/perf/util/hist.c | 7 +++++++
> 3 files changed, 22 insertions(+), 2 deletions(-)
>
> Apologies for the long lead time on this. This is the backport that
> I've been using to debug issues on 4.9 kernels in my production
> environment.
Not a problem, thanks for this, now applied.
greg k-h
prev parent reply other threads:[~2017-03-09 18:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-12 22:03 FAILED: patch "[PATCH] perf callchain: Reference count maps" failed to apply to 4.9-stable tree gregkh
2017-03-09 17:57 ` [PATCH stable-4.9] perf callchain: Reference count maps Krister Johansen
2017-03-09 18:45 ` Greg KH [this message]
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