4.14-stable review patch. If anyone has any objections, please let me know.
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From: Colin Ian King colin.king@canonical.com
[ Upstream commit 3993b112dac968612b0b213ed59cb30f50b0015b ]
There are checks on fs_info in __btrfs_panic to avoid dereferencing a null fs_info, however, there is a call to btrfs_crit that may also dereference a null fs_info. Fix this by adding a check to see if fs_info is null and only print the s_id if fs_info is non-null.
Detected by CoverityScan CID#401973 ("Dereference after null check")
Fixes: efe120a067c8 ("Btrfs: convert printk to btrfs_ and fix BTRFS prefix") Signed-off-by: Colin Ian King colin.king@canonical.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/super.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -202,7 +202,6 @@ static struct ratelimit_state printk_lim
void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...) { - struct super_block *sb = fs_info->sb; char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0"; struct va_format vaf; va_list args; @@ -228,7 +227,8 @@ void btrfs_printk(const struct btrfs_fs_ vaf.va = &args;
if (__ratelimit(ratelimit)) - printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf); + printk("%sBTRFS %s (device %s): %pV\n", lvl, type, + fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
va_end(args); }