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From: "홍신 shin hong" <hongshin@gmail.com>
To: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org
Subject: data race in remove_proc_entry()
Date: Wed, 4 Feb 2009 00:40:59 +0900	[thread overview]
Message-ID: <2014bcab0902030740y115b6179gb5c6ad5f1f2d994@mail.gmail.com> (raw)

Hi. I found a suspected bug in proc file system

At proc/generic.c line 806,  de->subdir is not protected by
spin_lock(&proc_subdir_lock)
so that data races might occur.

Line 806 must be protected by spin_lock(&proc_subdir_lock) to avoid data race.

WARN(condition , stmt) is translated into if (condition) { stmt }.
At line 806, a context switching can happen right after the condition checking
and another thread may set 'de->subdir' as a null.
In this case, the execution of 'stmt' would occur null pointer dereference error
since it has 'de->subdir->name'.

Sincerely,
Shin Hong
M.S. Candidate
Computer Science Div., EECS Dept.,
Korea Advanced Institute of Sci. & Tech.,
Republic of Korea

                 reply	other threads:[~2009-02-03 15:41 UTC|newest]

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