syzbot reports f2fs bug as below:

kernel BUG at fs/f2fs/inode.c:933! RIP: 0010:f2fs_evict_inode+0x1576/0x1590 fs/f2fs/inode.c:933 Call Trace: evict+0x2a4/0x620 fs/inode.c:664 dispose_list fs/inode.c:697 [inline] evict_inodes+0x5f8/0x690 fs/inode.c:747 generic_shutdown_super+0x9d/0x2c0 fs/super.c:675 kill_block_super+0x44/0x90 fs/super.c:1667 kill_f2fs_super+0x303/0x3b0 fs/f2fs/super.c:4894 deactivate_locked_super+0xc1/0x130 fs/super.c:484 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1256 task_work_run+0x24a/0x300 kernel/task_work.c:180 ptrace_notify+0x2cd/0x380 kernel/signal.c:2399 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline] syscall_exit_work kernel/entry/common.c:251 [inline] syscall_exit_to_user_mode_prepare kernel/entry/common.c:278 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x15c/0x280 kernel/entry/common.c:296 do_syscall_64+0x50/0x110 arch/x86/entry/common.c:88 entry_SYSCALL_64_after_hwframe+0x63/0x6b

The root cause is: - do_sys_open - f2fs_lookup - __f2fs_find_entry - f2fs_i_depth_write - f2fs_mark_inode_dirty_sync - f2fs_dirty_inode - set_inode_flag(inode, FI_DIRTY_INODE)

- umount - kill_f2fs_super - kill_block_super - generic_shutdown_super - sync_filesystem : sb is readonly, skip sync_filesystem() - evict_inodes - iput - f2fs_evict_inode - f2fs_bug_on(sbi, is_inode_flag_set(inode, FI_DIRTY_INODE)) : trigger kernel panic

When we try to repair i_current_depth in readonly filesystem, let's skip dirty inode to avoid panic in later f2fs_evict_inode().

Cc: stable@vger.kernel.org Reported-by: syzbot+31e4659a3fe953aec2f4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-f2fs-devel/000000000000e890bc0609a55cff@google... Signed-off-by: Chao Yu chao@kernel.org --- fs/f2fs/inode.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 8f2b9f62ef73..64cda1d77fe5 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -29,6 +29,9 @@ void f2fs_mark_inode_dirty_sync(struct inode *inode, bool sync) if (is_inode_flag_set(inode, FI_NEW_INODE)) return;

+ if (f2fs_readonly(F2FS_I_SB(inode)->sb)) + return; + if (f2fs_inode_dirtied(inode, sync)) return;