From: "Török Edwin" <edwintorok@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: srostedt@redhat.com, a.p.zijlstra@chello.nl,
sandmann@daimi.au.dk, linux-kernel@vger.kernel.org,
viro@ZenIV.linux.org.uk
Subject: Re: [PATCH 2/3] tracing/stack-tracer: fix locking
Date: Sun, 23 Nov 2008 12:59:03 +0200 [thread overview]
Message-ID: <49293777.8070404@gmail.com> (raw)
In-Reply-To: <20081123105211.GC30453@elte.hu>
On 2008-11-23 12:52, Ingo Molnar wrote:
> * Török Edwin <edwintorok@gmail.com> wrote:
>
>
>> + down_read(&mm->mmap_sem);
>> + vma = find_vma(mm, ip);
>> if (vma) {
>> file = vma->vm_file;
>> vmstart = vma->vm_start;
>> }
>> + up_read(&mm->mmap_sem);
>> }
>> if (file) {
>> ret = trace_seq_path(s, &file->f_path);
>>
>
> and now it's "file" that is held without a reference and possibly
> racy.
>
I'll move the (file) inside the mmap_sem too, since file is part of vma,
and you need mmap_sem to access the vma
nobody can modify (file) if they don't hold mmap_sem.
Am I right?
--Edwin
next prev parent reply other threads:[~2008-11-23 10:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-22 11:28 [PATCH 0/2] tracing: userspace stacktraces Török Edwin
2008-11-22 11:28 ` [PATCH 1/2] tracing: add support for userspace stacktraces in tracing/iter_ctrl Török Edwin
2008-11-23 8:37 ` Ingo Molnar
2008-11-23 10:39 ` [PATCH 3/3] tracing/stack-tracer: introduce CONFIG_USER_STACKTRACE_SUPPORT Török Edwin
2008-11-22 11:28 ` [PATCH 2/2] tracing: identify which executable object the userspace address belongs to Török Edwin
2008-11-23 8:47 ` [PATCH] vfs, seqfile: make mangle_path() global Ingo Molnar
2008-11-23 21:06 ` Randy Dunlap
2008-11-23 21:24 ` [PATCH] fix comment style on mangle_path Török Edwin
2008-11-23 21:36 ` Ingo Molnar
2008-11-28 10:05 ` [PATCH] vfs, seqfile: make mangle_path() global Al Viro
2008-11-28 17:08 ` Ingo Molnar
2008-11-23 8:53 ` [PATCH 2/2] tracing: identify which executable object the userspace address belongs to Ingo Molnar
2008-11-23 10:39 ` [PATCH 1/3] tracing/stack-tracer: fix style issues Török Edwin
2008-11-23 10:39 ` [PATCH 2/3] tracing/stack-tracer: fix locking Török Edwin
2008-11-23 10:52 ` Ingo Molnar
2008-11-23 10:59 ` Török Edwin [this message]
2008-11-23 11:01 ` Ingo Molnar
2008-11-23 11:04 ` Török Edwin
2008-11-23 11:07 ` Ingo Molnar
2008-11-23 11:08 ` [PATCH] tracing/stack-tracer: avoid races accessing file Török Edwin
2008-11-23 11:20 ` Ingo Molnar
2008-11-25 14:40 ` [PATCH 2/2] tracing: identify which executable object the userspace address belongs to Frank Ch. Eigler
2008-11-26 9:59 ` Török Edwin
2008-11-27 10:41 ` Peter Zijlstra
2008-11-27 12:48 ` Frank Ch. Eigler
2008-11-27 13:02 ` Peter Zijlstra
2008-11-27 13:03 ` Török Edwin
2008-11-27 14:10 ` Ingo Molnar
2008-11-27 14:27 ` Török Edwin
2008-11-27 14:51 ` Ingo Molnar
2008-12-09 19:49 ` Török Edwin
2008-11-23 8:26 ` [PATCH 0/2] tracing: userspace stacktraces Ingo Molnar
2008-11-23 9:24 ` Török Edwin
2008-11-23 9:30 ` Ingo Molnar
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