[PATCH AUTOSEL 6.10 1/7] f2fs: fix to do sanity check on F2FS_INLINE_DATA flag in inode during GC

Sasha Levin
2024-07-30T12:45:22Z

From: Chao Yu <chao@kernel.org>

[ Upstream commit fc01008c92f40015aeeced94750855a7111b6929 ]

syzbot reports a f2fs bug as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/inline.c:258!
CPU: 1 PID: 34 Comm: kworker/u8:2 Not tainted 6.9.0-rc6-syzkaller-00012-g9e4bc4bcae01 #0
RIP: 0010:f2fs_write_inline_data+0x781/0x790 fs/f2fs/inline.c:258
Call Trace:
f2fs_write_single_data_page+0xb65/0x1d60 fs/f2fs/data.c:2834
f2fs_write_cache_pages fs/f2fs/data.c:3133 [inline]
__f2fs_write_data_pages fs/f2fs/data.c:3288 [inline]
f2fs_write_data_pages+0x1efe/0x3a90 fs/f2fs/data.c:3315
do_writepages+0x35b/0x870 mm/page-writeback.c:2612
__writeback_single_inode+0x165/0x10b0 fs/fs-writeback.c:1650
writeback_sb_inodes+0x905/0x1260 fs/fs-writeback.c:1941
wb_writeback+0x457/0xce0 fs/fs-writeback.c:2117
wb_do_writeback fs/fs-writeback.c:2264 [inline]
wb_workfn+0x410/0x1090 fs/fs-writeback.c:2304
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f2/0x390 kernel/kthread.c:388
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The root cause is: inline_data inode can be fuzzed, so that there may
be valid blkaddr in its direct node, once f2fs triggers background GC
to migrate the block, it will hit f2fs_bug_on() during dirty page
writeback.

Let's add sanity check on F2FS_INLINE_DATA flag in inode during GC,
so that, it can forbid migrating inline_data inode's data block for
fixing.

Reported-by: syzbot+848062ba19c8782ca5c8@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/000000000000d103ce06174d7ec3@google.com
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/gc.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 6066c6eecf41d..20e2f989013b7 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1563,6 +1563,16 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
continue;
}

+ if (f2fs_has_inline_data(inode)) {
+ iput(inode);
+ set_sbi_flag(sbi, SBI_NEED_FSCK);
+ f2fs_err_ratelimited(sbi,
+ "inode %lx has both inline_data flag and "
+ "data block, nid=%u, ofs_in_node=%u",
+ inode->i_ino, dni.nid, ofs_in_node);
+ continue;
+ }
+
err = f2fs_gc_pinned_control(inode, gc_type, segno);
if (err == -EAGAIN) {
iput(inode);
--
2.43.0