Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 068/120] ext4: fix crash when accessing /proc/mounts concurrently | Date | Thu, 11 Oct 2012 10:00:20 +0900 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
commit 50df9fd55e4271e89a7adf3b1172083dd0ca199d upstream.
The crash was caused by a variable being erronously declared static in token2str().
In addition to /proc/mounts, the problem can also be easily replicated by accessing /proc/fs/ext4/<partition>/options in parallel:
$ cat /proc/fs/ext4/<partition>/options > options.txt
... and then running the following command in two different terminals:
$ while diff /proc/fs/ext4/<partition>/options options.txt; do true; done
This is also the cause of the following a crash while running xfstests #234, as reported in the following bug reports:
https://bugs.launchpad.net/bugs/1053019 https://bugzilla.kernel.org/show_bug.cgi?id=47731
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Brad Figg <brad.figg@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext4/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1692,7 +1692,7 @@ static inline void ext4_show_quota_optio static const char *token2str(int token) { - static const struct match_token *t; + const struct match_token *t; for (t = tokens; t->token != Opt_err; t++) if (t->token == token && !strchr(t->pattern, '='))
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