On 3/31/20 12:18 PM, Dmitry Vyukov wrote: > On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra <pet...@infradead.org> wrote: >> >> On Mon, Mar 30, 2020 at 10:01:12PM -0700, syzbot wrote: >>> Hello, >>> >>> syzbot found the following crash on: >>> >>> HEAD commit: 9420e8ad Merge tag 'for-linus' of git://git.kernel.org/pub.. >>> git tree: upstream >>> console output: >>> https://protect2.fireeye.com/url?k=0756a78d-5a9a6c49-07572cc2-0cc47a314e9a-e4dc8b657d340686&u=https://syzkaller.appspot.com/x/log.txt?x=1206ed4be00000 >>> kernel config: >>> https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3bd45a19932c37c8&u=https://syzkaller.appspot.com/x/.config?x=27392dd2975fd692 >>> dashboard link: >>> https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c64073ee605efb7b&u=https://syzkaller.appspot.com/bug?extid=e84d7ebd1361da13c356 >>> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >>> >>> Unfortunately, I don't have any reproducer for this crash yet. >>> >>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>> Reported-by: syzbot+e84d7ebd1361da13c...@syzkaller.appspotmail.com >>> >>> INFO: trying to register non-static key. >>> the code is fine but needs lockdep annotation. >>> turning off the locking correctness validator. >>> CPU: 1 PID: 1014 Comm: syz-executor.0 Not tainted 5.6.0-rc7-syzkaller #0 >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >>> Google 01/01/2011 >>> Call Trace: >>> <IRQ> >>> __dump_stack lib/dump_stack.c:77 [inline] >>> dump_stack+0x188/0x20d lib/dump_stack.c:118 >>> assign_lock_key kernel/locking/lockdep.c:880 [inline] >>> register_lock_class+0x14c4/0x1540 kernel/locking/lockdep.c:1189 >>> __lock_acquire+0xfc/0x3ca0 kernel/locking/lockdep.c:3836 >>> lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484 >>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] >>> _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159 >>> try_to_wake_up+0x9f/0x17c0 kernel/sched/core.c:2547 >> >> That's p->pi_lock, which gets initialized in rt_mutex_init_task() in >> copy_process(). This should be impossible. Very odd. > > The stack mentions fbdev, which is a red flag at the moment. There are > a dozen of bad bugs in fbdev and around. Just few days ago Andy > pointed to another "impossible" crash "general protection fault in > do_syscall_64" which is related to dri: > https://protect2.fireeye.com/url?k=0cb8ad06-517466c2-0cb92649-0cc47a314e9a-a20c11191483c65b&u=https://syzkaller.appspot.com/bug?id=0ec7b2602b1ff40f0d34f38baa4ba1640727c3d9 > https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-aeda6d72c01a7b0e&u=https://groups.google.com/forum/#!msg/syzkaller-bugs/ePqhfYx0-8M/Q_Urt97iAAAJ > > There are probably more random manifestations of these bugs already, > and I guess we will be getting more. > > +fbdev maintainers
Thank you for the report. fbdev is in the maintenance mode and no new features or drivers are being added so syzbot reports are not for a new bugs (regressions) and are not a priority (at least to me). I have only resources to review/merge pending fbdev patches from time to time so any help in fixing these syzbot reports is welcomed (there have been a few fbdev related syzbot reports recently). Also please note that fbdev is maintained through drm-misc tree so patches can also be handled by other drm-misc maintainers in case I'm not available / busy with other things. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics >>> wake_up_worker kernel/workqueue.c:836 [inline] >>> insert_work+0x2ad/0x3a0 kernel/workqueue.c:1337 >>> __queue_work+0x50d/0x1280 kernel/workqueue.c:1488 >>> call_timer_fn+0x195/0x760 kernel/time/timer.c:1404 >>> expire_timers kernel/time/timer.c:1444 [inline] >>> __run_timers kernel/time/timer.c:1773 [inline] >>> __run_timers kernel/time/timer.c:1740 [inline] >>> run_timer_softirq+0x412/0x1600 kernel/time/timer.c:1786 >>> __do_softirq+0x26c/0x99d kernel/softirq.c:292 >>> invoke_softirq kernel/softirq.c:373 [inline] >>> irq_exit+0x192/0x1d0 kernel/softirq.c:413 >>> exiting_irq arch/x86/include/asm/apic.h:546 [inline] >>> smp_apic_timer_interrupt+0x19e/0x600 arch/x86/kernel/apic/apic.c:1146 >>> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 >>> </IRQ> _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
