3.16.54-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
commit 3993b112dac968612b0b213ed59cb30f50b0015b upstream.
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@xxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
fs/btrfs/super.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -185,7 +185,6 @@ static const char * const logtypes[] = {
void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
{
- struct super_block *sb = fs_info->sb;
char lvl[4];
struct va_format vaf;
va_list args;
@@ -207,7 +206,8 @@ void btrfs_printk(const struct btrfs_fs_
vaf.fmt = fmt;
vaf.va = &args;
- 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);
}