On Thu, Aug 24, 2017 at 02:03:57PM +0300, Dan Carpenter wrote:
> Hello Bob Peterson,
>
> The patch 9bfef7554e20: "GFS2: Withdraw for IO errors writing to the
> journal or statfs" from Aug 16, 2017, leads to the following static
> checker warning:
>
> fs/gfs2/super.c:949 gfs2_sync_fs()
> error: we previously assumed 'sdp' could be null (see line 947)
>
> fs/gfs2/super.c
> 942 static int gfs2_sync_fs(struct super_block *sb, int wait)
> 943 {
> 944 struct gfs2_sbd *sdp = sb->s_fs_info;
> 945
> 946 gfs2_quota_sync(sb, -1);
> 947 if (wait && sdp)
> ^^^
> Existing code checks for NULL.
The NULL check seemed odd to me, and other ->sync_fs implementations don't
check it, but digging through the history there's a reason it was added (see
9171f5a ). That said, I can't see the quota_off code path that it was guarding
against any more, so perhaps it is no longer required.
Andy
>
> 948 gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
> 949 return sdp->sd_log_error;
> ^^^^^^^^^^^^^^^^^
> Patch adds unchecked dereference.
