Messages in this thread | | | From | Dmitry Vyukov <> | Date | Thu, 5 Dec 2019 13:06:23 +0100 | Subject | Re: kernel BUG at fs/btrfs/volumes.c:LINE! |
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On Thu, Dec 5, 2019 at 12:50 PM David Sterba <dsterba@suse.cz> wrote: > > On Thu, Dec 05, 2019 at 12:38:38PM +0100, Johannes Thumshirn wrote: > > On Thu, Dec 05, 2019 at 11:07:27AM +0100, Dmitry Vyukov wrote: > > > The correct syntax would be (no dash + colon): > > > > > > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/jth/linux.git > > > close_fs_devices > > > > Ah ok, thanks. > > > > Although syzbot already said it can't test because it has no reproducer. > > Anyways good to know for future reports. > > According to > > https://syzkaller.appspot.com/bug?id=d50670eeb21302915bde3f25871dfb7ea43db1e4 > > there is a way how to test it, many reports and the last one about a > week old. Is there a way to instruct syzbot to run the same tests on a > given branch? > > (The reproducer is basically setting up environment with limited amount > of memory available for allocation and this hits the BUG_ON.)
syzkaller does this ("rerun the same tests") for every bug always. If it succeeds (kernel crashes again), it results in a reproducer, that can later be used for cause/fix bisection and patch testing. In this case it does not reproduce, so rerunning the same tests will not lead to anything useful (only if to false confirmation that a patch fixes the crash).
There is a large number of reasons why a kernel crash may not reproduce. It may be global accumulated state, non-hermetic tests, poor syzkaller btrfs descriptions (most likely true) and others.
Need to take a closer look, on first sight it looks like something that should be reproduced...
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