On Sun, Feb 28, 2016 at 9:01 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > On Sun, Feb 28, 2016 at 05:01:34PM +0000, Al Viro wrote: > >> Erm... What's to order ->d_inode and ->d_flags fetches there? David? >> Looks like the barrier in d_is_negative() is on the wrong side of fetch. >> Confused... > > OK, as per David's suggestion, let's flip them around, bringing the > barrier in d_is_negative() between them. Dmitry, could you try this on > top of mainline? Again, it's until the first warning. Good news, I was able to trigger these warnings on a plain C program: https://gist.githubusercontent.com/dvyukov/1a81426b8a5dd3620d6f/raw/fe6d03cfb0d219ad3d979f8bd6c016a5a1b93212/gistfile1.txt Unfortunately, the failure rate is significantly lower than with syzkaller. Syzkaller triggered it 8 times in 18 hours on a single VM; while the C program triggered it once on 2 VMs. Al, maybe you can modify the program to increase failure rate? I would expect that we need to clash 2 (or maybe 3) syscalls with right timing to trigger it. You must have a better idea as to what are these syscalls. P.S. this is still with the previous patch, not the latest one. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
