ext4: fix crash when accessing /proc/mounts concurrently
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>
Cc: stable@vger.kernel.org
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e6784b3..7bef0a4 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1749,7 +1749,7 @@
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, '='))