On Tue, 17 Sep 2019, Dmitry Vyukov wrote: > On Mon, Sep 16, 2019 at 10:31 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Mon, 16 Sep 2019, syzbot wrote: > > > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: 014077b5 DO-NOT-SUBMIT: usb-fuzzer: main usb gadget fuzzer.. > > > git tree: https://github.com/google/kmsan.git master > > > console output: https://syzkaller.appspot.com/x/log.txt?x=16a7dde1600000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d > > > dashboard link: https://syzkaller.appspot.com/bug?extid=e1d1a6e595adbd2458f1 > > > compiler: clang version 9.0.0 (/home/glider/llvm/clang > > > 80fee25776c2fb61e74c1ecb1a523375c2500b69) > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=176303e1600000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e8f23e600000 > > This is probably the same problem that was fixed in the Logitech driver > > earlier. The fix still appears to be in linux-next (commit > > 5f9242775bb6). > > > > Shouldn't syzbot wait until after the merge window before running tests > > like this? > > > Merge window is a weak notion and may be not enough either (all trees > do not necessary update at that point and syzbot does not necessary > rebuild all of them successfully). syzbot uses another criteria: if > you say a bug is fixed by commit X, it will wait until commit X > reaches all of tested trees and will report the same crash signature > again only after that. This procedure was specifically designed to not > produce duplicate reports about the same bug. > So either the bug wasn't really fixed, or this is another bug, or > syzbot was given a wrong commit. Hmmm. Which are the "tested trees"? This bug (e1d1a6e595adbd2458f1) is marked as a duplicate of 3cbe5cd105d2ad56a1df. The dashboard link says that bug was fixed by commit "HID: logitech: Fix general protection fault caused by Logitech driver" -- which is correct, as far as I know. That commit is present in linux-next, as mentioned above. As of 10:44 EDT today, it is not present in Linus's tree, according to https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/hid/hid-lg.c (in fact, no commits affecting drivers/hid/hid-lg.c in that tree are dated after 2019-07-10). Furthermore, according to https://github.com/google/kmsan/blob/master/drivers/hid/hid-lg.c?h=014077b5 the source code actually used by syzbot for this test doesn't have that commit either. (BTW, is there any way to get a git log out of github? It would be nice not to have to download the whole source file -- and I'm not certain that this URL really does point to the version of the file that syzbot used.) So what's really going on? Alan Stern
