Don't pass error pointers to brelse().
commit 7159a986b4 ("ext4: fix some error pointer dereferences") has fixed
some cases, fix the remaining one case.
Once ext4_xattr_block_find()->ext4_sb_bread() failed, error pointer is
stored in @bs->bh, which will be passed to brelse() in the cleanup
routine of ext4_xattr_set_handle(). This will then cause a NULL panic
crash in __brelse().
BUG: unable to handle kernel NULL pointer dereference at 000000000000005b
RIP: 0010:__brelse+0x1b/0x50
Call Trace:
ext4_xattr_set_handle+0x163/0x5d0
ext4_xattr_set+0x95/0x110
__vfs_setxattr+0x6b/0x80
__vfs_setxattr_noperm+0x68/0x1b0
vfs_setxattr+0xa0/0xb0
setxattr+0x12c/0x1a0
path_setxattr+0x8d/0xc0
__x64_sys_setxattr+0x27/0x30
do_syscall_64+0x60/0x250
entry_SYSCALL_64_after_hwframe+0x49/0xbe
In this case, @bs->bh stores '-EIO' actually.
Fixes: fb265c9cb4 ("ext4: add ext4_sb_bread() to disambiguate ENOMEM cases")
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: stable@kernel.org # 2.6.19
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1587628004-95123-1-git-send-email-jefflexu@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8418897f1b