On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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://syzkaller.appspot.com/x/log.txt?x=1206ed4be00000 kernel config: https://syzkaller.appspot.com/x/.config?x=27392dd2975fd692 dashboard link: 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+e84d7ebd1361da13c356@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://syzkaller.appspot.com/bug?id=0ec7b2602b1ff40f0d34f38baa4ba1640727c3d... https://groups.google.com/forum/#!msg/syzkaller-bugs/ePqhfYx0-8M/Q_Urt97iAAA...
There are probably more random manifestations of these bugs already, and I guess we will be getting more.
+fbdev maintainers
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>
-- You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20200331095737.GO20730%40hi....
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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>
On Tue, Mar 31, 2020 at 2:18 PM Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com wrote:
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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).
Yup same here, I've seen a pile of syzbot reports for fbdev (and also vt, or combinations of them since fbdev is linked to vt through fbcon) fly by. But I really don't have to deal with these, my recommendation to anyone who cares about security are: - Don't enable vt - Don't enable fbdev
All that code has been developed long ago, in a much more innocent time. If someone wants to fix this you'd not just need to fix all the syzbot stuff, but also ramp up a full testsuite for all the ioctl, and all the corner-cases. Plus also fix some of the horrendous locking in there, probably.
Multi-year effort, easily.
Regressions I'll obviously try to handle, but none of these are. It's just syzbot has become smarter at hitting bugs in fbdev and vt subsystems (or maybe the hw the virtual machines emulate has become more varied, some of the reports are for fun stuff like vgacon ...).
Cheers, Daniel
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
On Tue, Mar 31, 2020 at 2:50 PM Daniel Vetter daniel@ffwll.ch wrote:
On Tue, Mar 31, 2020 at 2:18 PM Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com wrote:
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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).
Yup same here, I've seen a pile of syzbot reports for fbdev (and also vt, or combinations of them since fbdev is linked to vt through fbcon) fly by. But I really don't have to deal with these, my recommendation to anyone who cares about security are:
- Don't enable vt
- Don't enable fbdev
All that code has been developed long ago, in a much more innocent time. If someone wants to fix this you'd not just need to fix all the syzbot stuff, but also ramp up a full testsuite for all the ioctl, and all the corner-cases. Plus also fix some of the horrendous locking in there, probably.
Multi-year effort, easily.
Regressions I'll obviously try to handle, but none of these are. It's just syzbot has become smarter at hitting bugs in fbdev and vt subsystems (or maybe the hw the virtual machines emulate has become more varied, some of the reports are for fun stuff like vgacon ...).
Forgot to mention: Just yesterday I did merge an fbcon overflow bugfix: commit b139f8b00db4a8ea75a4174346eafa48041aa489 (HEAD -> drm-misc-next-fixes, drm-misc/for-linux-next, drm-misc/drm-misc-next-fixes) Author: Qiujun Huang hqjagain@gmail.com Date: Sun Mar 29 16:56:47 2020 +0800
fbcon: fix null-ptr-deref in fbcon_switch
There's also a pending patch in the vt subsystem to catch overflow for unicode fonts on consoles, that's reviewed and waiting for Greg to pick it up. -Daniel
Cheers, Daniel
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
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Tue, Mar 31, 2020 at 2:50 PM Daniel Vetter daniel@ffwll.ch wrote:
On Tue, Mar 31, 2020 at 2:18 PM Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com wrote:
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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).
Yup same here, I've seen a pile of syzbot reports for fbdev (and also vt, or combinations of them since fbdev is linked to vt through fbcon) fly by. But I really don't have to deal with these, my recommendation to anyone who cares about security are:
- Don't enable vt
- Don't enable fbdev
1. How do we deliver this message to relevant people?
Because:
$ grep FBDEV syzkaller/dashboard/config/upstream-kasan.config CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
and my current work machine:
$ grep FBDEV /boot/config-5.2.17-1-amd64 CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
2. What do we do with fbdev testing on syzbot? Is there a way to disable all of the unsupported stuff? But if we disable it, we don't find any regressions as well. And in the end that's what is in the mainline kernel and is still enabled in distros (at least in the 2 real configs I can grep now).
All that code has been developed long ago, in a much more innocent time. If someone wants to fix this you'd not just need to fix all the syzbot stuff, but also ramp up a full testsuite for all the ioctl, and all the corner-cases. Plus also fix some of the horrendous locking in there, probably.
Multi-year effort, easily.
Regressions I'll obviously try to handle, but none of these are. It's just syzbot has become smarter at hitting bugs in fbdev and vt subsystems (or maybe the hw the virtual machines emulate has become more varied, some of the reports are for fun stuff like vgacon ...).
Cheers, Daniel
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
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Apr 1, 2020 at 10:47 AM Dmitry Vyukov dvyukov@google.com wrote:
On Tue, Mar 31, 2020 at 2:50 PM Daniel Vetter daniel@ffwll.ch wrote:
On Tue, Mar 31, 2020 at 2:18 PM Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com wrote:
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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).
Yup same here, I've seen a pile of syzbot reports for fbdev (and also vt, or combinations of them since fbdev is linked to vt through fbcon) fly by. But I really don't have to deal with these, my recommendation to anyone who cares about security are:
- Don't enable vt
- Don't enable fbdev
- How do we deliver this message to relevant people?
Because:
$ grep FBDEV syzkaller/dashboard/config/upstream-kasan.config CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
and my current work machine:
$ grep FBDEV /boot/config-5.2.17-1-amd64 CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
Yeah I know it's been like this since forever. In theory you could build a fbdev/fbcon less distro since years (the last bit for a proof of concept was kmscon/systemd-consoled), but the amount of investment into classic linux desktop is so little that it's impossible to get this funded. CrOS fixed this a while ago iirc though.
I think to fix the syzbot issues all we'd need is a competent intern for a few months, that should take care of the worst stuff. Obviously wont include getting a test suite going, nor fixing any of the fundamental issues. But duct-taping over all the bugs should be possible (it's what we've been doing for well over 10 years by now in fbdev/fbocn/vt code anyway). I'd be willing to help mentoring, but that's about all I can do.
Adding Matthew Garret, I have discussed with him in the past finding some funding for linux desktop stuff like this.
- What do we do with fbdev testing on syzbot? Is there a way to
disable all of the unsupported stuff? But if we disable it, we don't find any regressions as well. And in the end that's what is in the mainline kernel and is still enabled in distros (at least in the 2 real configs I can grep now).
This would be bad I agree, but it's not any worse than the state of things the past 10 years. That's roughly for as long as fbdev has been in maintainance only mode, meaning "we'll apply patches if they come". Without Bart volunteering, we wouldn't even have that much really. -Daniel
All that code has been developed long ago, in a much more innocent time. If someone wants to fix this you'd not just need to fix all the syzbot stuff, but also ramp up a full testsuite for all the ioctl, and all the corner-cases. Plus also fix some of the horrendous locking in there, probably.
Multi-year effort, easily.
Regressions I'll obviously try to handle, but none of these are. It's just syzbot has become smarter at hitting bugs in fbdev and vt subsystems (or maybe the hw the virtual machines emulate has become more varied, some of the reports are for fun stuff like vgacon ...).
Cheers, Daniel
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
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Apr 1, 2020 at 10:59 AM Daniel Vetter daniel@ffwll.ch wrote:
On Wed, Apr 1, 2020 at 10:47 AM Dmitry Vyukov dvyukov@google.com wrote:
On Tue, Mar 31, 2020 at 2:50 PM Daniel Vetter daniel@ffwll.ch wrote:
On Tue, Mar 31, 2020 at 2:18 PM Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com wrote:
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... > kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... > dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... > 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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).
Yup same here, I've seen a pile of syzbot reports for fbdev (and also vt, or combinations of them since fbdev is linked to vt through fbcon) fly by. But I really don't have to deal with these, my recommendation to anyone who cares about security are:
- Don't enable vt
- Don't enable fbdev
- How do we deliver this message to relevant people?
Because:
$ grep FBDEV syzkaller/dashboard/config/upstream-kasan.config CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
and my current work machine:
$ grep FBDEV /boot/config-5.2.17-1-amd64 CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
Yeah I know it's been like this since forever. In theory you could build a fbdev/fbcon less distro since years (the last bit for a proof of concept was kmscon/systemd-consoled), but the amount of investment into classic linux desktop is so little that it's impossible to get this funded. CrOS fixed this a while ago iirc though.
I think to fix the syzbot issues all we'd need is a competent intern for a few months, that should take care of the worst stuff. Obviously wont include getting a test suite going, nor fixing any of the fundamental issues. But duct-taping over all the bugs should be possible (it's what we've been doing for well over 10 years by now in fbdev/fbocn/vt code anyway). I'd be willing to help mentoring, but that's about all I can do.
Adding Matthew Garret, I have discussed with him in the past finding some funding for linux desktop stuff like this.
- What do we do with fbdev testing on syzbot? Is there a way to
disable all of the unsupported stuff? But if we disable it, we don't find any regressions as well. And in the end that's what is in the mainline kernel and is still enabled in distros (at least in the 2 real configs I can grep now).
This would be bad I agree, but it's not any worse than the state of things the past 10 years. That's roughly for as long as fbdev has been in maintainance only mode, meaning "we'll apply patches if they come". Without Bart volunteering, we wouldn't even have that much really.
Oh wrt disabling fbdev: Make sure CONFIG_FB isn't set. Unfortunately a pile of other things select that, for convenience (like CONFIG_DRM_KMS_FB_HELPER).
That should get rid of all the problematic fbdev code.
From what I've seen in some of the syzbot mails flying by we also have
issues in vt and console code blowing up (not just on fbcon/fbdev, but also e.g. on vgacon). That stuff you'll still hit. But maybe you can trick Greg KH into fixing the vt/console.c issues, he just claimed that :-P -Daniel
All that code has been developed long ago, in a much more innocent time. If someone wants to fix this you'd not just need to fix all the syzbot stuff, but also ramp up a full testsuite for all the ioctl, and all the corner-cases. Plus also fix some of the horrendous locking in there, probably.
Multi-year effort, easily.
Regressions I'll obviously try to handle, but none of these are. It's just syzbot has become smarter at hitting bugs in fbdev and vt subsystems (or maybe the hw the virtual machines emulate has become more varied, some of the reports are for fun stuff like vgacon ...).
Cheers, Daniel
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
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Apr 1, 2020 at 11:06 AM Daniel Vetter daniel@ffwll.ch wrote:
On Tue, Mar 31, 2020 at 2:18 PM Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com wrote:
On 3/31/20 12:18 PM, Dmitry Vyukov wrote:
On Tue, Mar 31, 2020 at 11:57 AM Peter Zijlstra peterz@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-e... >> kernel config: https://protect2.fireeye.com/url?k=43211072-1eeddbb6-43209b3d-0cc47a314e9a-3... >> dashboard link: https://protect2.fireeye.com/url?k=bf7a6153-e2b6aa97-bf7bea1c-0cc47a314e9a-c... >> 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+e84d7ebd1361da13c356@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-a... https://protect2.fireeye.com/url?k=614292e3-3c8e5927-614319ac-0cc47a314e9a-a...
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).
Yup same here, I've seen a pile of syzbot reports for fbdev (and also vt, or combinations of them since fbdev is linked to vt through fbcon) fly by. But I really don't have to deal with these, my recommendation to anyone who cares about security are:
- Don't enable vt
- Don't enable fbdev
- How do we deliver this message to relevant people?
Because:
$ grep FBDEV syzkaller/dashboard/config/upstream-kasan.config CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
and my current work machine:
$ grep FBDEV /boot/config-5.2.17-1-amd64 CONFIG_DRM_FBDEV_EMULATION=y CONFIG_DRM_FBDEV_OVERALLOC=100 # CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM is not set CONFIG_XEN_FBDEV_FRONTEND=y
Yeah I know it's been like this since forever. In theory you could build a fbdev/fbcon less distro since years (the last bit for a proof of concept was kmscon/systemd-consoled), but the amount of investment into classic linux desktop is so little that it's impossible to get this funded. CrOS fixed this a while ago iirc though.
I think to fix the syzbot issues all we'd need is a competent intern for a few months, that should take care of the worst stuff. Obviously wont include getting a test suite going, nor fixing any of the fundamental issues. But duct-taping over all the bugs should be possible (it's what we've been doing for well over 10 years by now in fbdev/fbocn/vt code anyway). I'd be willing to help mentoring, but that's about all I can do.
Adding Matthew Garret, I have discussed with him in the past finding some funding for linux desktop stuff like this.
I will keep this in mind. We _may_ get some interns this year who _may_ be interested in fixing Linux kernel bugs (but otherwise extending syzkaller descriptions).
FTR, there is also some follow up on twitter re extending https://github.com/a13xp0p0v/kconfig-hardened-check to capture such recommendations: https://twitter.com/dvyukov/status/1245969522869309441 https://github.com/a13xp0p0v/kconfig-hardened-check/issues/38
- What do we do with fbdev testing on syzbot? Is there a way to
disable all of the unsupported stuff? But if we disable it, we don't find any regressions as well. And in the end that's what is in the mainline kernel and is still enabled in distros (at least in the 2 real configs I can grep now).
This would be bad I agree, but it's not any worse than the state of things the past 10 years. That's roughly for as long as fbdev has been in maintainance only mode, meaning "we'll apply patches if they come". Without Bart volunteering, we wouldn't even have that much really.
Oh wrt disabling fbdev: Make sure CONFIG_FB isn't set. Unfortunately a pile of other things select that, for convenience (like CONFIG_DRM_KMS_FB_HELPER).
That should get rid of all the problematic fbdev code.
From what I've seen in some of the syzbot mails flying by we also have issues in vt and console code blowing up (not just on fbcon/fbdev, but also e.g. on vgacon). That stuff you'll still hit. But maybe you can trick Greg KH into fixing the vt/console.c issues, he just claimed that :-P -Daniel
All that code has been developed long ago, in a much more innocent time. If someone wants to fix this you'd not just need to fix all the syzbot stuff, but also ramp up a full testsuite for all the ioctl, and all the corner-cases. Plus also fix some of the horrendous locking in there, probably.
Multi-year effort, easily.
Regressions I'll obviously try to handle, but none of these are. It's just syzbot has become smarter at hitting bugs in fbdev and vt subsystems (or maybe the hw the virtual machines emulate has become more varied, some of the reports are for fun stuff like vgacon ...).
Cheers, Daniel
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
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
dri-devel@lists.freedesktop.org
-
Bartlomiej Zolnierkiewicz -
Daniel Vetter -
Dmitry Vyukov