diff options
author | Greg Thelen <gthelen@google.com> | 2013-02-23 01:36:02 +0100 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-24 02:50:23 +0100 |
commit | 49cd0a5c290f99deca3463d16c3c1c7240107889 (patch) | |
tree | 90a7f92f4b48463483644270355006419bd0f9af /mm/shmem.c | |
parent | tmpfs: fix use-after-free of mempolicy object (diff) | |
download | linux-49cd0a5c290f99deca3463d16c3c1c7240107889.tar.xz linux-49cd0a5c290f99deca3463d16c3c1c7240107889.zip |
tmpfs: fix mempolicy object leaks
Fix several mempolicy leaks in the tmpfs mount logic. These leaks are
slow - on the order of one object leaked per mount attempt.
Leak 1 (umount doesn't free mpol allocated in mount):
while true; do
mount -t tmpfs -o mpol=interleave,size=100M nodev /mnt
umount /mnt
done
Leak 2 (errors parsing remount options will leak mpol):
mount -t tmpfs -o size=100M nodev /mnt
while true; do
mount -o remount,mpol=interleave,size=x /mnt 2> /dev/null
done
umount /mnt
Leak 3 (multiple mpol per mount leak mpol):
while true; do
mount -t tmpfs -o mpol=interleave,mpol=interleave,size=100M nodev /mnt
umount /mnt
done
This patch fixes all of the above. I could have broken the patch into
three pieces but is seemed easier to review as one.
[akpm@linux-foundation.org: fix handling of mpol_parse_str() errors, per Hugh]
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
-rw-r--r-- | mm/shmem.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 5e2ff592e3b8..1ad79243cb7b 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2385,6 +2385,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, bool remount) { char *this_char, *value, *rest; + struct mempolicy *mpol = NULL; uid_t uid; gid_t gid; @@ -2413,7 +2414,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, printk(KERN_ERR "tmpfs: No value for mount option '%s'\n", this_char); - return 1; + goto error; } if (!strcmp(this_char,"size")) { @@ -2462,19 +2463,24 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, if (!gid_valid(sbinfo->gid)) goto bad_val; } else if (!strcmp(this_char,"mpol")) { - if (mpol_parse_str(value, &sbinfo->mpol)) + mpol_put(mpol); + mpol = NULL; + if (mpol_parse_str(value, &mpol)) goto bad_val; } else { printk(KERN_ERR "tmpfs: Bad mount option %s\n", this_char); - return 1; + goto error; } } + sbinfo->mpol = mpol; return 0; bad_val: printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", value, this_char); +error: + mpol_put(mpol); return 1; } @@ -2550,6 +2556,7 @@ static void shmem_put_super(struct super_block *sb) struct shmem_sb_info *sbinfo = SHMEM_SB(sb); percpu_counter_destroy(&sbinfo->used_blocks); + mpol_put(sbinfo->mpol); kfree(sbinfo); sb->s_fs_info = NULL; } |