[PATCH] f2fs: fix double free of f2fs_sb_info

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

kill_f2fs_super() is called even if f2fs_fill_super() fails.
f2fs_fill_super() frees the struct f2fs_sb_info, so it must set
sb->s_fs_info to NULL to prevent it from being freed again.

Fixes: 275dca4630c1 ("f2fs: move release of block devices to after kill_block_super()")
Reported-by: syzbot+8f477ac014ff5b32d81f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/0000000000006cb174060ec34502@google.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/f2fs/super.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index d00d21a8b53ad..d45ab0992ae59 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4873,20 +4873,21 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		kfree(F2FS_OPTION(sbi).s_qf_names[i]);
 #endif
 	fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy);
 	kvfree(options);
 free_sb_buf:
 	kfree(raw_super);
 free_sbi:
 	if (sbi->s_chksum_driver)
 		crypto_free_shash(sbi->s_chksum_driver);
 	kfree(sbi);
+	sb->s_fs_info = NULL;
 
 	/* give only one another chance */
 	if (retry_cnt > 0 && skip_recovery) {
 		retry_cnt--;
 		shrink_dcache_sb(sb);
 		goto try_onemore;
 	}
 	return err;
 }
 

base-commit: 38814330fedd778edffcabe0c8cb462ee365782e
-- 
2.43.0