From 49cd0a5c290f99deca3463d16c3c1c7240107889 Mon Sep 17 00:00:00 2001 From: Greg Thelen Date: Fri, 22 Feb 2013 16:36:02 -0800 Subject: [PATCH] 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 Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/shmem.c | 13 ++++++++++--- 1 file 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; }