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[PATCH AUTOSEL 5.1 048/186] f2fs: fix to clear dirty inode in error path of f2fs_iget()




From: Chao Yu <yuchao0@xxxxxxxxxx>

[ Upstream commit 546d22f070d64a7b96f57c93333772085d3a5e6d ]

As Jungyeon reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=203217

- Overview
When mounting the attached crafted image and running program, I got this error.
Additionally, it hangs on sync after running the program.

The image is intentionally fuzzed from a normal f2fs image for testing and I enabled option CONFIG_F2FS_CHECK_FS on.

- Reproduces
cc poc_test_05.c
mkdir test
mount -t f2fs tmp.img test
sudo ./a.out
sync

- Messages
 kernel BUG at fs/f2fs/inode.c:707!
 RIP: 0010:f2fs_evict_inode+0x33f/0x3a0
 Call Trace:
  evict+0xba/0x180
  f2fs_iget+0x598/0xdf0
  f2fs_lookup+0x136/0x320
  __lookup_slow+0x92/0x140
  lookup_slow+0x30/0x50
  walk_component+0x1c1/0x350
  path_lookupat+0x62/0x200
  filename_lookup+0xb3/0x1a0
  do_readlinkat+0x56/0x110
  __x64_sys_readlink+0x16/0x20
  do_syscall_64+0x43/0xf0
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

During inode loading, __recover_inline_status() can recovery inode status
and set inode dirty, once we failed in following process, it will fail
the check in f2fs_evict_inode, result in trigger BUG_ON().

Let's clear dirty inode in error path of f2fs_iget() to avoid panic.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/f2fs/inode.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index e7f2e87593156..4edd6f2bb4910 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -488,6 +488,7 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 	return inode;
 
 bad_inode:
+	f2fs_inode_synced(inode);
 	iget_failed(inode);
 	trace_f2fs_iget_exit(inode, ret);
 	return ERR_PTR(ret);
-- 
2.20.1