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authorPavel Skripkin <paskripkin@gmail.com>2021-04-30 21:50:46 +0300
committerTheodore Ts'o <tytso@mit.edu>2021-06-17 10:53:19 -0400
commit618f003199c6188e01472b03cdbba227f1dc5f24 (patch)
tree6f73f2324cae9f4d4c58606b793d8261273723a8 /fs/ext4/mmp.c
parent1fc57ca5a2cd26e0a526e5eb2b0fc0c054117a5b (diff)
ext4: fix memory leak in ext4_fill_super
static int kthread(void *_create) will return -ENOMEM or -EINTR in case of internal failure or kthread_stop() call happens before threadfn call. To prevent fancy error checking and make code more straightforward we moved all cleanup code out of kmmpd threadfn. Also, dropped struct mmpd_data at all. Now struct super_block is a threadfn data and struct buffer_head embedded into struct ext4_sb_info. Reported-by: syzbot+d9e482e303930fa4f6ff@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Link: https://lore.kernel.org/r/20210430185046.15742-1-paskripkin@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mmp.c')
-rw-r--r--fs/ext4/mmp.c28
1 files changed, 13 insertions, 15 deletions
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 68fbeedd627b..6cb598b549ca 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -127,9 +127,9 @@ void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
*/
static int kmmpd(void *data)
{
- struct super_block *sb = ((struct mmpd_data *) data)->sb;
- struct buffer_head *bh = ((struct mmpd_data *) data)->bh;
+ struct super_block *sb = (struct super_block *) data;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+ struct buffer_head *bh = EXT4_SB(sb)->s_mmp_bh;
struct mmp_struct *mmp;
ext4_fsblk_t mmp_block;
u32 seq = 0;
@@ -245,12 +245,18 @@ static int kmmpd(void *data)
retval = write_mmp_block(sb, bh);
exit_thread:
- EXT4_SB(sb)->s_mmp_tsk = NULL;
- kfree(data);
- brelse(bh);
return retval;
}
+void ext4_stop_mmpd(struct ext4_sb_info *sbi)
+{
+ if (sbi->s_mmp_tsk) {
+ kthread_stop(sbi->s_mmp_tsk);
+ brelse(sbi->s_mmp_bh);
+ sbi->s_mmp_tsk = NULL;
+ }
+}
+
/*
* Get a random new sequence number but make sure it is not greater than
* EXT4_MMP_SEQ_MAX.
@@ -275,7 +281,6 @@ int ext4_multi_mount_protect(struct super_block *sb,
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
struct buffer_head *bh = NULL;
struct mmp_struct *mmp = NULL;
- struct mmpd_data *mmpd_data;
u32 seq;
unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
unsigned int wait_time = 0;
@@ -364,24 +369,17 @@ skip:
goto failed;
}
- mmpd_data = kmalloc(sizeof(*mmpd_data), GFP_KERNEL);
- if (!mmpd_data) {
- ext4_warning(sb, "not enough memory for mmpd_data");
- goto failed;
- }
- mmpd_data->sb = sb;
- mmpd_data->bh = bh;
+ EXT4_SB(sb)->s_mmp_bh = bh;
/*
* Start a kernel thread to update the MMP block periodically.
*/
- EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, mmpd_data, "kmmpd-%.*s",
+ EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, sb, "kmmpd-%.*s",
(int)sizeof(mmp->mmp_bdevname),
bdevname(bh->b_bdev,
mmp->mmp_bdevname));
if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
EXT4_SB(sb)->s_mmp_tsk = NULL;
- kfree(mmpd_data);
ext4_warning(sb, "Unable to create kmmpd thread for %s.",
sb->s_id);
goto failed;