We should return when io->bio is null before doing anything. Otherwise, panic.

BUG: kernel NULL pointer dereference, address: 0000000000000010 RIP: 0010:__submit_merged_write_cond+0x164/0x240 [f2fs] Call Trace: <TASK> f2fs_submit_merged_write+0x1d/0x30 [f2fs] commit_checkpoint+0x110/0x1e0 [f2fs] f2fs_write_checkpoint+0x9f7/0xf00 [f2fs] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] __checkpoint_and_complete_reqs+0x84/0x190 [f2fs] ? preempt_count_add+0x82/0xc0 ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] issue_checkpoint_thread+0x4c/0xf0 [f2fs] ? __pfx_autoremove_wake_function+0x10/0x10 kthread+0xff/0x130 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 </TASK>

Cc: stable@vger.kernel.org # v5.18+ Fixes: 64bf0eef0171 ("f2fs: pass the bio operation to bio_alloc_bioset") Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org --- fs/f2fs/data.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 12f233f2fd58..ea8311a58ab7 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -653,6 +653,9 @@ static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi,

f2fs_down_write(&io->io_rwsem);

+ if (!io->bio) + goto unlock_out; + /* change META to META_FLUSH in the checkpoint procedure */ if (type >= META_FLUSH) { io->fio.type = META_FLUSH; @@ -661,6 +664,7 @@ static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi, io->bio->bi_opf |= REQ_PREFLUSH | REQ_FUA; } __submit_merged_bio(io); +unlock_out: f2fs_up_write(&io->io_rwsem); }