On Mon, 17 May 2021 16:40:34 +0300 Pavel Skripkin <paskripkin@xxxxxxxxx> wrote: > Hi! > > Is all ok with this one, or I should send v3? :) > BTW, this patch fixes this bug as well https://syzkaller.appspot.com/bug?id=e2765a883959fd094e6a1c40f3502114fa17c550 With regards, Pavel Skripkin > With regards, > Pavel Skripkin > > On Fri, 30 Apr 2021 21:50:46 +0300 > Pavel Skripkin <paskripkin@xxxxxxxxx> wrote: > > 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@xxxxxxxxxxxxxxxxxxxxxxxxx > > Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> > > --- > > fs/ext4/ext4.h | 4 ++++ > > fs/ext4/mmp.c | 28 +++++++++++++--------------- > > fs/ext4/super.c | 10 ++++------ > > 3 files changed, 21 insertions(+), 21 deletions(-) > > > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > > index 826a56e3bbd2..62210cbea84b 100644 > > --- a/fs/ext4/ext4.h > > +++ b/fs/ext4/ext4.h > > @@ -1490,6 +1490,7 @@ struct ext4_sb_info { > > struct kobject s_kobj; > > struct completion s_kobj_unregister; > > struct super_block *s_sb; > > + struct buffer_head *s_mmp_bh; > > > > /* Journaling */ > > struct journal_s *s_journal; > > @@ -3663,6 +3664,9 @@ extern struct ext4_io_end_vec > > *ext4_last_io_end_vec(ext4_io_end_t *io_end); /* mmp.c */ > > extern int ext4_multi_mount_protect(struct super_block *, > > ext4_fsblk_t); > > +/* mmp.c */ > > +extern void ext4_stop_mmpd(struct ext4_sb_info *sbi); > > + > > /* verity.c */ > > extern const struct fsverity_operations ext4_verityops; > > > > diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c > > index 795c3ff2907c..623bad399612 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 @@ int ext4_multi_mount_protect(struct > > super_block *sb, 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; > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > > index b9693680463a..539f89c5431f 100644 > > --- a/fs/ext4/super.c > > +++ b/fs/ext4/super.c > > @@ -1244,8 +1244,8 @@ static void ext4_put_super(struct super_block > > *sb) ext4_xattr_destroy_cache(sbi->s_ea_block_cache); > > sbi->s_ea_block_cache = NULL; > > > > - if (sbi->s_mmp_tsk) > > - kthread_stop(sbi->s_mmp_tsk); > > + ext4_stop_mmpd(sbi); > > + > > brelse(sbi->s_sbh); > > sb->s_fs_info = NULL; > > /* > > @@ -5156,8 +5156,7 @@ static int ext4_fill_super(struct super_block > > *sb, void *data, int silent) failed_mount3: > > flush_work(&sbi->s_error_work); > > del_timer_sync(&sbi->s_err_report); > > - if (sbi->s_mmp_tsk) > > - kthread_stop(sbi->s_mmp_tsk); > > + ext4_stop_mmpd(sbi); > > failed_mount2: > > rcu_read_lock(); > > group_desc = rcu_dereference(sbi->s_group_desc); > > @@ -5952,8 +5951,7 @@ static int ext4_remount(struct super_block > > *sb, int *flags, char *data) */ > > ext4_mark_recovery_complete(sb, > > es); } > > - if (sbi->s_mmp_tsk) > > - kthread_stop(sbi->s_mmp_tsk); > > + ext4_stop_mmpd(sbi); > > } else { > > /* Make sure we can mount this feature set > > readwrite */ if (ext4_has_feature_readonly(sb) || >
