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* [PATCH v1] f2fs: fix NULL pointer dereference in f2fs_submit_page_write()
@ 2024-01-16 14:11 Wenjie Qi
  2024-01-16 21:58 ` [f2fs-dev] " Daeho Jeong
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Wenjie Qi @ 2024-01-16 14:11 UTC (permalink / raw)
  To: jaegeuk, chao, linux-f2fs-devel, linux-kernel; +Cc: hustqwj, Wenjie Qi

BUG: kernel NULL pointer dereference, address: 0000000000000014
RIP: 0010:f2fs_submit_page_write+0x6cf/0x780 [f2fs]
Call Trace:
<TASK>
? show_regs+0x6e/0x80
? __die+0x29/0x70
? page_fault_oops+0x154/0x4a0
? prb_read_valid+0x20/0x30
? __irq_work_queue_local+0x39/0xd0
? irq_work_queue+0x36/0x70
? do_user_addr_fault+0x314/0x6c0
? exc_page_fault+0x7d/0x190
? asm_exc_page_fault+0x2b/0x30
? f2fs_submit_page_write+0x6cf/0x780 [f2fs]
? f2fs_submit_page_write+0x736/0x780 [f2fs]
do_write_page+0x50/0x170 [f2fs]
f2fs_outplace_write_data+0x61/0xb0 [f2fs]
f2fs_do_write_data_page+0x3f8/0x660 [f2fs]
f2fs_write_single_data_page+0x5bb/0x7a0 [f2fs]
f2fs_write_cache_pages+0x3da/0xbe0 [f2fs]
...
It is possible that other threads have added this fio to io->bio
and submitted the io->bio before entering f2fs_submit_page_write().
At this point io->bio = NULL.
If is_end_zone_blkaddr(sbi, fio->new_blkaddr) of this fio is true,
then an NULL pointer dereference error occurs at bio_get(io->bio).
The original code for determining zone end was after "out:",
which would have missed some fio who is zone end. I've moved
 this code before "skip:" to make sure it's done for each fio.

Signed-off-by: Wenjie Qi <qwjhust@gmail.com>
---
 fs/f2fs/data.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index dce8defdf4c7..4f445906db8b 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1080,10 +1080,6 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	io->last_block_in_bio = fio->new_blkaddr;
 
 	trace_f2fs_submit_page_write(fio->page, fio);
-skip:
-	if (fio->in_list)
-		goto next;
-out:
 #ifdef CONFIG_BLK_DEV_ZONED
 	if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
 			is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
@@ -1096,6 +1092,10 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 		__submit_merged_bio(io);
 	}
 #endif
+skip:
+	if (fio->in_list)
+		goto next;
+out:
 	if (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
 				!f2fs_is_checkpoint_ready(sbi))
 		__submit_merged_bio(io);
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2024-01-29 20:29 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-01-16 14:11 [PATCH v1] f2fs: fix NULL pointer dereference in f2fs_submit_page_write() Wenjie Qi
2024-01-16 21:58 ` [f2fs-dev] " Daeho Jeong
2024-01-17  1:39   ` Wenjie Qi
2024-01-17 10:17     ` Yongpeng Yang
2024-01-17 11:27       ` Wenjie Qi
2024-01-29 10:27 ` Chao Yu
2024-01-29 11:16   ` [f2fs-dev] " Chao Yu
2024-01-29 20:29 ` patchwork-bot+f2fs

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