* general protection fault in process_one_work @ 2019-10-29 8:38 syzbot 2019-10-29 8:43 ` Dmitry Vyukov 0 siblings, 1 reply; 5+ messages in thread From: syzbot @ 2019-10-29 8:38 UTC (permalink / raw) To: ast, bpf, daniel, davem, jakub.kicinski, kafai, linux-kernel, netdev, songliubraving, syzkaller-bugs, yhs Hello, syzbot found the following crash on: HEAD commit: 38207291 bpf: Prepare btf_ctx_access for non raw_tp use case git tree: bpf-next console output: https://syzkaller.appspot.com/x/log.txt?x=14173c0f600000 kernel config: https://syzkaller.appspot.com/x/.config?x=41648156aa09be10 dashboard link: https://syzkaller.appspot.com/bug?extid=9ed8f68ab30761f3678e 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+9ed8f68ab30761f3678e@syzkaller.appspotmail.com kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 9149 Comm: kworker/1:3 Not tainted 5.4.0-rc1+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_dev_trap_report_work RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 drivers/net/netdevsim/dev.c:409 Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Modules linked in: ---[ end trace ba29cd1c27f63d86 ]--- RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 drivers/net/netdevsim/dev.c:409 Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: general protection fault in process_one_work 2019-10-29 8:38 general protection fault in process_one_work syzbot @ 2019-10-29 8:43 ` Dmitry Vyukov 2019-10-29 8:45 ` Ido Schimmel 0 siblings, 1 reply; 5+ messages in thread From: Dmitry Vyukov @ 2019-10-29 8:43 UTC (permalink / raw) To: syzbot, Jiri Pirko Cc: Alexei Starovoitov, bpf, Daniel Borkmann, David Miller, Jakub Kicinski, Martin KaFai Lau, LKML, netdev, Song Liu, syzkaller-bugs, Yonghong Song On Tue, Oct 29, 2019 at 9:38 AM syzbot <syzbot+9ed8f68ab30761f3678e@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 38207291 bpf: Prepare btf_ctx_access for non raw_tp use case > git tree: bpf-next > console output: https://syzkaller.appspot.com/x/log.txt?x=14173c0f600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=41648156aa09be10 > dashboard link: https://syzkaller.appspot.com/bug?extid=9ed8f68ab30761f3678e > 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+9ed8f68ab30761f3678e@syzkaller.appspotmail.com +Jiří Pírko, this seems to be related to netdevsim. > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] PREEMPT SMP KASAN > CPU: 1 PID: 9149 Comm: kworker/1:3 Not tainted 5.4.0-rc1+ #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: events nsim_dev_trap_report_work > RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 > drivers/net/netdevsim/dev.c:409 > Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef > fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 > 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 > RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 > RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 > RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 > RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 > R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 > R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 > worker_thread+0x98/0xe40 kernel/workqueue.c:2415 > kthread+0x361/0x430 kernel/kthread.c:255 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > Modules linked in: > ---[ end trace ba29cd1c27f63d86 ]--- > RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 > drivers/net/netdevsim/dev.c:409 > Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef > fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 > 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 > RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 > RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 > RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 > RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 > R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 > R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > 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/0000000000001c46d5059608892f%40google.com. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: general protection fault in process_one_work 2019-10-29 8:43 ` Dmitry Vyukov @ 2019-10-29 8:45 ` Ido Schimmel 2019-10-29 16:54 ` Ido Schimmel 0 siblings, 1 reply; 5+ messages in thread From: Ido Schimmel @ 2019-10-29 8:45 UTC (permalink / raw) To: Dmitry Vyukov Cc: syzbot, Jiri Pirko, Alexei Starovoitov, bpf, Daniel Borkmann, David Miller, Jakub Kicinski, Martin KaFai Lau, LKML, netdev, Song Liu, syzkaller-bugs, Yonghong Song On Tue, Oct 29, 2019 at 09:43:27AM +0100, Dmitry Vyukov wrote: > On Tue, Oct 29, 2019 at 9:38 AM syzbot > <syzbot+9ed8f68ab30761f3678e@syzkaller.appspotmail.com> wrote: > > > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 38207291 bpf: Prepare btf_ctx_access for non raw_tp use case > > git tree: bpf-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=14173c0f600000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=41648156aa09be10 > > dashboard link: https://syzkaller.appspot.com/bug?extid=9ed8f68ab30761f3678e > > 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+9ed8f68ab30761f3678e@syzkaller.appspotmail.com > > +Jiří Pírko, this seems to be related to netdevsim. Will check it. > > > kasan: CONFIG_KASAN_INLINE enabled > > kasan: GPF could be caused by NULL-ptr deref or user memory access > > general protection fault: 0000 [#1] PREEMPT SMP KASAN > > CPU: 1 PID: 9149 Comm: kworker/1:3 Not tainted 5.4.0-rc1+ #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Workqueue: events nsim_dev_trap_report_work > > RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 > > drivers/net/netdevsim/dev.c:409 > > Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef > > fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 > > 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 > > RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 > > RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 > > RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 > > RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 > > R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 > > R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 > > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 > > worker_thread+0x98/0xe40 kernel/workqueue.c:2415 > > kthread+0x361/0x430 kernel/kthread.c:255 > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > Modules linked in: > > ---[ end trace ba29cd1c27f63d86 ]--- > > RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 > > drivers/net/netdevsim/dev.c:409 > > Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef > > fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 > > 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 > > RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 > > RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 > > RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 > > RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 > > R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 > > R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 > > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > > > --- > > This bug is generated by a bot. It may contain errors. > > See https://goo.gl/tpsmEJ for more information about syzbot. > > syzbot engineers can be reached at syzkaller@googlegroups.com. > > > > syzbot will keep track of this bug report. See: > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > > > -- > > 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/0000000000001c46d5059608892f%40google.com. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: general protection fault in process_one_work 2019-10-29 8:45 ` Ido Schimmel @ 2019-10-29 16:54 ` Ido Schimmel 2019-10-31 16:25 ` Ido Schimmel 0 siblings, 1 reply; 5+ messages in thread From: Ido Schimmel @ 2019-10-29 16:54 UTC (permalink / raw) To: Dmitry Vyukov Cc: syzbot, Jiri Pirko, Alexei Starovoitov, bpf, Daniel Borkmann, David Miller, Jakub Kicinski, Martin KaFai Lau, LKML, netdev, Song Liu, syzkaller-bugs, Yonghong Song On Tue, Oct 29, 2019 at 10:45:19AM +0200, Ido Schimmel wrote: > On Tue, Oct 29, 2019 at 09:43:27AM +0100, Dmitry Vyukov wrote: > > On Tue, Oct 29, 2019 at 9:38 AM syzbot > > <syzbot+9ed8f68ab30761f3678e@syzkaller.appspotmail.com> wrote: > > > > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: 38207291 bpf: Prepare btf_ctx_access for non raw_tp use case > > > git tree: bpf-next > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14173c0f600000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=41648156aa09be10 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=9ed8f68ab30761f3678e > > > 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+9ed8f68ab30761f3678e@syzkaller.appspotmail.com > > > > +Jiří Pírko, this seems to be related to netdevsim. > > Will check it. Didn't have a lot of time today, but I think the issue is a race condition (note that syzbot only triggered it twice so far). Upon reload nsim_dev_port_del_all() is called and starts deleting ports from the ports list without holding the ports list mutex. It is possible that during this time nsim_dev_trap_report_work() is executing from a workqueue and accessing freed memory despite holding the ports list mutex. I'll try to reproduce and send a fix later this week. > > > > > > kasan: CONFIG_KASAN_INLINE enabled > > > kasan: GPF could be caused by NULL-ptr deref or user memory access > > > general protection fault: 0000 [#1] PREEMPT SMP KASAN > > > CPU: 1 PID: 9149 Comm: kworker/1:3 Not tainted 5.4.0-rc1+ #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > > Google 01/01/2011 > > > Workqueue: events nsim_dev_trap_report_work > > > RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 > > > drivers/net/netdevsim/dev.c:409 > > > Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef > > > fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 > > > 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 > > > RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 > > > RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 > > > RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 > > > RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 > > > R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 > > > R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 > > > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Call Trace: > > > process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 > > > worker_thread+0x98/0xe40 kernel/workqueue.c:2415 > > > kthread+0x361/0x430 kernel/kthread.c:255 > > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > > Modules linked in: > > > ---[ end trace ba29cd1c27f63d86 ]--- > > > RIP: 0010:nsim_dev_trap_report_work+0xc4/0xaf0 > > > drivers/net/netdevsim/dev.c:409 > > > Code: 89 45 d0 0f 84 8b 07 00 00 49 bc 00 00 00 00 00 fc ff df e8 3e ae ef > > > fc 48 8b 45 d0 48 05 68 01 00 00 48 89 45 90 48 c1 e8 03 <42> 80 3c 20 00 > > > 0f 85 b1 09 00 00 48 8b 45 d0 48 8b 98 68 01 00 00 > > > RSP: 0018:ffff88806c98fc90 EFLAGS: 00010a06 > > > RAX: 1bd5a0000000004d RBX: 0000000000000000 RCX: ffffffff84836e22 > > > RDX: 0000000000000000 RSI: ffffffff84836db2 RDI: 0000000000000001 > > > RBP: ffff88806c98fd30 R08: ffff88806c9863c0 R09: ffffed100d75f3d9 > > > R10: ffffed100d75f3d8 R11: ffff88806baf9ec7 R12: dffffc0000000000 > > > R13: ffff88806baf9ec0 R14: ffff8880a9a13900 R15: ffff8880ae934500 > > > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00007efdd0c9e000 CR3: 000000009cc1b000 CR4: 00000000001406e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > > > > > > --- > > > This bug is generated by a bot. It may contain errors. > > > See https://goo.gl/tpsmEJ for more information about syzbot. > > > syzbot engineers can be reached at syzkaller@googlegroups.com. > > > > > > syzbot will keep track of this bug report. See: > > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > > > > > -- > > > 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/0000000000001c46d5059608892f%40google.com. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: general protection fault in process_one_work 2019-10-29 16:54 ` Ido Schimmel @ 2019-10-31 16:25 ` Ido Schimmel 0 siblings, 0 replies; 5+ messages in thread From: Ido Schimmel @ 2019-10-31 16:25 UTC (permalink / raw) To: Dmitry Vyukov Cc: syzbot, Jiri Pirko, Alexei Starovoitov, bpf, Daniel Borkmann, David Miller, Jakub Kicinski, Martin KaFai Lau, LKML, netdev, Song Liu, syzkaller-bugs, Yonghong Song On Tue, Oct 29, 2019 at 06:54:07PM +0200, Ido Schimmel wrote: > On Tue, Oct 29, 2019 at 10:45:19AM +0200, Ido Schimmel wrote: > > On Tue, Oct 29, 2019 at 09:43:27AM +0100, Dmitry Vyukov wrote: > > > On Tue, Oct 29, 2019 at 9:38 AM syzbot > > > <syzbot+9ed8f68ab30761f3678e@syzkaller.appspotmail.com> wrote: > > > > > > > > Hello, > > > > > > > > syzbot found the following crash on: > > > > > > > > HEAD commit: 38207291 bpf: Prepare btf_ctx_access for non raw_tp use case > > > > git tree: bpf-next > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14173c0f600000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=41648156aa09be10 > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=9ed8f68ab30761f3678e > > > > 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+9ed8f68ab30761f3678e@syzkaller.appspotmail.com > > > > > > +Jiří Pírko, this seems to be related to netdevsim. > > > > Will check it. > > Didn't have a lot of time today, but I think the issue is a race > condition (note that syzbot only triggered it twice so far). > > Upon reload nsim_dev_port_del_all() is called and starts deleting ports > from the ports list without holding the ports list mutex. It is possible > that during this time nsim_dev_trap_report_work() is executing from a > workqueue and accessing freed memory despite holding the ports list > mutex. > > I'll try to reproduce and send a fix later this week. Sent a fix: https://patchwork.ozlabs.org/patch/1187587/ It was quite difficult to reproduce, so I used the below patch to increase the time window in which the race could occur. Then it became trivial to trigger :) diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c index 54ca6681ba31..d12abd84c218 100644 --- a/drivers/net/netdevsim/dev.c +++ b/drivers/net/netdevsim/dev.c @@ -457,6 +457,7 @@ static void nsim_dev_trap_report_work(struct work_struct *work) */ mutex_lock(&nsim_dev->port_list_lock); list_for_each_entry(nsim_dev_port, &nsim_dev->port_list, list) { + msleep(100); if (!netif_running(nsim_dev_port->ns->netdev)) continue; ^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-10-31 16:25 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-10-29 8:38 general protection fault in process_one_work syzbot 2019-10-29 8:43 ` Dmitry Vyukov 2019-10-29 8:45 ` Ido Schimmel 2019-10-29 16:54 ` Ido Schimmel 2019-10-31 16:25 ` Ido Schimmel
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