Hi Park,
Thanks for the report, could have a try with below patch:
From 5fa30e8cdcb93f210e25142c48a884be383c6121 Mon Sep 17 00:00:00 2001
From: Chao Yu <
yuchao0@huawei.com>
Date: Mon, 2 Oct 2017 02:50:16 +0800
Subject: [PATCH] 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>
---
fs/f2fs/f2fs.h | 2 +-
fs/f2fs/segment.c | 6 +++---
fs/f2fs/super.c | 2 +-
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9a7c90386947..4b4a72f392be 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2525,7 +2525,7 @@ void invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
bool is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
void refresh_sit_entry(struct f2fs_sb_info *sbi, block_t old, block_t new);
void stop_discard_thread(struct f2fs_sb_info *sbi);
-void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
+void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi, bool umount);
void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc);
void release_discard_addrs(struct f2fs_sb_info *sbi);
int npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index dedf0209d820..e28245b7e44e 100644
--- a/fs/f2fs/segment.c
+++ b/