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| author |   Chao Yu <yuchao0@huawei.com> | 2017-10-02 02:50:16 +0800 |
|---|---|---|
| committer |   Jaegeuk Kim <jaegeuk@kernel.org> | 2017-10-03 08:06:05 -0700 |
| commit | 638164a2718f337ea224b747cf5977ef143166a4 (patch) | |
| tree | eb00daa4d3fea717977c5bea6caf3f6d08726031 /fs/f2fs/super.c | |
| parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs (diff) | |
| download | linux-dev-638164a2718f337ea224b747cf5977ef143166a4.tar.xz linux-dev-638164a2718f337ea224b747cf5977ef143166a4.zip | |
f2fs: fix potential panic during fstrim
As Ju Hyung Park reported:
"When 'fstrim' is called for manual trim, a BUG() can be triggered
randomly with this patch.
I'm seeing this issue on both x86 Desktop and arm64 Android phone.
On x86 Desktop, this was caused during Ubuntu boot-up. I have a
cronjob installed which calls 'fstrim -v /' during boot. On arm64
Android, this was caused during GC looping with 1ms gc_min_sleep_time
& gc_max_sleep_time."
Root cause of this issue is that f2fs_wait_discard_bios can only be
used by f2fs_put_super, because during put_super there must be no
other referrers, so it can ignore discard entry's reference count
when removing the entry, otherwise in other caller we will hit bug_on
in __remove_discard_cmd as there may be other issuer added reference
count in discard entry.
Thread A Thread B
- issue_discard_thread
- f2fs_ioc_fitrim
- f2fs_trim_fs
- f2fs_wait_discard_bios
- __issue_discard_cmd
- __submit_discard_cmd
- __wait_discard_cmd
- dc->ref++
- __wait_one_discard_bio
- __wait_discard_cmd
- __remove_discard_cmd
- f2fs_bug_on(sbi, dc->ref)
Fixes: 969d1b180d987c2be02de890d0fff0f66a0e80de
Reported-by: Ju Hyung Park <qkrwngud825@gmail.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/super.c')
| -rw-r--r-- | fs/f2fs/super.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 89f61eb3d167..933c3d529e65 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -801,7 +801,7 @@ static void f2fs_put_super(struct super_block *sb) } /* be sure to wait for any on-going discard commands */ - f2fs_wait_discard_bios(sbi); + f2fs_wait_discard_bios(sbi, true); if (f2fs_discard_en(sbi) && !sbi->discard_blks) { struct cp_control cpc = { |