On Mon, Jun 22, 2020 at 09:15:32AM -0700, Darrick J. Wong wrote: > On Sun, Jun 21, 2020 at 04:03:02AM +0800, kernel test robot wrote: > > CC: kbuild-all@xxxxxxxxxxxx > > CC: linux-kernel@xxxxxxxxxxxxxxx > > TO: Dave Chinner <dchinner@xxxxxxxxxx> > > CC: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx> > > CC: Christoph Hellwig <hch@xxxxxx> > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > head: 4333a9b0b67bb4e8bcd91bdd80da80b0ec151162 > > commit: b0dff466c00975a3e3ec97e6b0266bfd3e4805d6 xfs: separate read-only variables in struct xfs_mount > > date: 3 weeks ago > > :::::: branch date: 24 hours ago > > :::::: commit date: 3 weeks ago > > config: i386-randconfig-m021-20200621 (attached as .config) > > compiler: gcc-9 (Debian 9.3.0-13) 9.3.0 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > > > > New smatch warnings: > > fs/xfs/libxfs/xfs_bmap.c:5563 __xfs_bunmapi() warn: Function too hairy. No more merges. > > > > Old smatch warnings: > > fs/xfs/libxfs/xfs_bmap.c:5450 __xfs_bunmapi() error: we previously assumed 'tp' could be null (see line 5290) > > fs/xfs/libxfs/xfs_bmap.c:6123 __xfs_bmap_add() error: potential null dereference 'bi'. (kmem_alloc returns null) > > Er... does this mean that smatch is smarter about kmem_alloc now? > > Or merely that something/someone tweaked the hair threshold downwards? > > <-- his personal hair threshold is much longer now that it's March 98th. You must have signed up to the kbuild list. I normally look over the warnings and ignore the false positives like this one... The "Function too hairy. No more merges." message is internal stuff. I should turn that off by default. I don't normally pay a lot of attention to the old warnings but it looks like the "tp" warning is valid. On my system, I don't get the warning because the "too hairy" warning triggers to early. The __xfs_bmap_add() warning is a false positive because we don't pass KM_MAYFAIL. Smatch doesn't track set bits. It will do eventually. It's not complicated code to write but it's just a matter of doing the work. regards, dan carpenter
