* Re: INFO: task hung in bpf_exit_net
@ 2017-12-22 10:58 ` Dmitry Vyukov
0 siblings, 0 replies; 15+ messages in thread
From: Dmitry Vyukov @ 2017-12-22 10:58 UTC (permalink / raw)
To: David Ahern
Cc: syzbot, LKML, Ingo Molnar, Peter Zijlstra, syzkaller-bugs,
David Miller, Florian Westphal, Daniel Borkmann, Xin Long,
jakub.kicinski, mschiffer, Vladislav Yasevich, Jiri Benc, netdev,
Neil Horman, linux-sctp
On Tue, Dec 19, 2017 at 7:20 PM, David Ahern <dsahern@gmail.com> wrote:
> On 12/19/17 5:47 AM, Dmitry Vyukov wrote:
>> On Tue, Dec 19, 2017 at 1:36 PM, syzbot
>> <bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller.appspotmail.com>
>> wrote:
>>> Hello,
>>>
>>> syzkaller hit the following crash on
>>> 7ceb97a071e80f1b5e4cd5a36de135612a836388
>>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
>>> compiler: gcc (GCC) 7.1.1 20170620
>>> .config is attached
>>> Raw console output is attached.
>>>
>>> Unfortunately, I don't have any reproducer for this bug yet.
>>>
>>>
>>> sctp: sctp_transport_update_pmtu: Reported pmtu 508 too low, using default
>>> minimum of 512
>>> INFO: task kworker/u4:0:5 blocked for more than 120 seconds.
>>> Not tainted 4.15.0-rc2-next-20171205+ #59
>>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>>> kworker/u4:0 D15808 5 2 0x80000000
>>> Workqueue: netns cleanup_net
>>> Call Trace:
>>> context_switch kernel/sched/core.c:2800 [inline]
>>> __schedule+0x8eb/0x2060 kernel/sched/core.c:3376
>>> schedule+0xf5/0x430 kernel/sched/core.c:3435
>>> schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493
>>> __mutex_lock_common kernel/locking/mutex.c:833 [inline]
>>> __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
>>> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
>>> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
>>> tc_action_net_exit include/net/act_api.h:125 [inline]
>>> bpf_exit_net+0x1a2/0x340 net/sched/act_bpf.c:408
>>> ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
>>> cleanup_net+0x5c7/0xb60 net/core/net_namespace.c:484
>>> process_one_work+0xbfd/0x1bc0 kernel/workqueue.c:2113
>>> worker_thread+0x223/0x1990 kernel/workqueue.c:2247
>>> kthread+0x37a/0x440 kernel/kthread.c:238
>>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
>>>
>>> Showing all locks held in the system:
>>> 4 locks held by kworker/u4:0/5:
>>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>>> __write_once_size include/linux/compiler.h:212 [inline]
>>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
>>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>>> set_work_data kernel/workqueue.c:619 [inline]
>>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
>>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
>>> #1: (net_cleanup_work){+.+.}, at: [<000000006c7c48a3>]
>>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
>>> #2: (net_mutex){+.+.}, at: [<00000000bf4709f3>] cleanup_net+0x247/0xb60
>>> net/core/net_namespace.c:450
>>> #3: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
>>> net/core/rtnetlink.c:74
>>> 3 locks held by kworker/1:0/17:
>>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>>> __write_once_size include/linux/compiler.h:212 [inline]
>>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
>>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>>> set_work_data kernel/workqueue.c:619 [inline]
>>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
>>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
>>> #1: ((addr_chk_work).work){+.+.}, at: [<000000006c7c48a3>]
>>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
>>> #2: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
>>> net/core/rtnetlink.c:74
>>> 2 locks held by khungtaskd/675:
>>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>]
>>> check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
>>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>] watchdog+0x1c5/0xd60
>>> kernel/hung_task.c:249
>>> #1: (tasklist_lock){.+.+}, at: [<000000005288685e>]
>>> debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
>>> 1 lock held by rsyslogd/2974:
>>> #0: (&f->f_pos_lock){+.+.}, at: [<0000000011e00499>]
>>> __fdget_pos+0x131/0x1a0 fs/file.c:770
>>> 2 locks held by getty/3056:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>> 2 locks held by getty/3057:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>> 2 locks held by getty/3058:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>> 2 locks held by getty/3059:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>> 2 locks held by getty/3060:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>> 2 locks held by getty/3061:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>> 2 locks held by getty/3062:
>>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>>>
>>> =============================================
>>>
>>> NMI backtrace for cpu 0
>>> CPU: 0 PID: 675 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171205+ #59
>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>> Google 01/01/2011
>>> Call Trace:
>>> __dump_stack lib/dump_stack.c:17 [inline]
>>> dump_stack+0x194/0x257 lib/dump_stack.c:53
>>> nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
>>> nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
>>> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
>>> trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
>>> check_hung_task kernel/hung_task.c:132 [inline]
>>> check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
>>> watchdog+0x90c/0xd60 kernel/hung_task.c:249
>>> kthread+0x37a/0x440 kernel/kthread.c:238
>>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
>>> Sending NMI from CPU 0 to CPUs 1:
>>> NMI backtrace for cpu 1
>>> CPU: 1 PID: 13156 Comm: syz-executor7 Not tainted 4.15.0-rc2-next-20171205+
>>> #59
>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>> Google 01/01/2011
>>> task: 000000005209c120 task.stack: 00000000ffaab0e8
>>> RIP: 0010:inb arch/x86/include/asm/io.h:348 [inline]
>>> RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:434
>>> RSP: 0018:ffff8801c0a16e70 EFLAGS: 00000002
>>> RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
>>> RDX: 00000000000003fd RSI: ffffc90003745000 RDI: ffffffff87cf1a40
>>> RBP: ffff8801c0a16e80 R08: 0000000000000005 R09: 000000000000000c
>>> R10: 0000000000000000 R11: ffffffff8748dd20 R12: ffffffff87cf1a00
>>> R13: 0000000000000020 R14: fffffbfff0f9e387 R15: fffffbfff0f9e34a
>>> FS: 00007f6d52e3f700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> CR2: 000000c42005de80 CR3: 00000001c368a000 CR4: 00000000001406e0
>>> DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
>>> Call Trace:
>>> serial_in drivers/tty/serial/8250/8250.h:111 [inline]
>>> wait_for_xmitr+0x93/0x1e0 drivers/tty/serial/8250/8250_port.c:2033
>>> serial8250_console_putchar+0x1f/0x60
>>> drivers/tty/serial/8250/8250_port.c:3170
>>> uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1858
>>> serial8250_console_write+0x647/0xa20
>>> drivers/tty/serial/8250/8250_port.c:3236
>>> univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590
>>> call_console_drivers kernel/printk/printk.c:1574 [inline]
>>> console_unlock+0x788/0xd70 kernel/printk/printk.c:2233
>>> vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757
>>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
>>> vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
>>> printk+0xaa/0xca kernel/printk/printk.c:1829
>>> nla_parse+0x374/0x3d0 lib/nlattr.c:257
>>> nlmsg_parse include/net/netlink.h:398 [inline]
>>> nl80211_dump_wiphy_parse.isra.37.constprop.83+0x138/0x5c0
>>> net/wireless/nl80211.c:1920
>>> nl80211_dump_interface+0x596/0x820 net/wireless/nl80211.c:2660
>>> genl_lock_dumpit+0x68/0x90 net/netlink/genetlink.c:480
>>> netlink_dump+0x48c/0xce0 net/netlink/af_netlink.c:2186
>>> __netlink_dump_start+0x4f0/0x6d0 net/netlink/af_netlink.c:2283
>>> genl_family_rcv_msg+0xd27/0xfc0 net/netlink/genetlink.c:548
>>> genl_rcv_msg+0xb2/0x140 net/netlink/genetlink.c:624
>>> netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2405
>>> genl_rcv+0x28/0x40 net/netlink/genetlink.c:635
>>> netlink_unicast_kernel net/netlink/af_netlink.c:1272 [inline]
>>> netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1298
>>> netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1861
>>> sock_sendmsg_nosec net/socket.c:636 [inline]
>>> sock_sendmsg+0xca/0x110 net/socket.c:646
>>> sock_write_iter+0x320/0x5e0 net/socket.c:915
>>> call_write_iter include/linux/fs.h:1776 [inline]
>>> new_sync_write fs/read_write.c:469 [inline]
>>> __vfs_write+0x68a/0x970 fs/read_write.c:482
>>> vfs_write+0x18f/0x510 fs/read_write.c:544
>>> SYSC_write fs/read_write.c:589 [inline]
>>> SyS_write+0xef/0x220 fs/read_write.c:581
>>> entry_SYSCALL_64_fastpath+0x1f/0x96
>>> RIP: 0033:0x4529d9
>>> RSP: 002b:00007f6d52e3ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
>>> RAX: ffffffffffffffda RBX: 00007f6d52e3f700 RCX: 00000000004529d9
>>> RDX: 0000000000000024 RSI: 0000000020454000 RDI: 0000000000000016
>>> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
>>> R13: 0000000000a6f7ff R14: 00007f6d52e3f9c0 R15: 0000000000000000
>>> Code: 24 d9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa
>>> 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 40 89 da ec <5b> 0f b6 c0 41
>>> 5c 5d c3 e8 38 b0 18 ff eb c2 e8 91 b0 18 ff eb
>>>
>>>
>>> ---
>>> This bug is generated by a dumb bot. It may contain errors.
>>> See https://goo.gl/tpsmEJ for details.
>>> Direct all questions to syzkaller@googlegroups.com.
>>> Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>
>>>
>>> syzbot will keep track of this bug report.
>>> Once a fix for this bug is merged into any tree, reply to this email with:
>>> #syz fix: exact-commit-title
>>> To mark this as a duplicate of another syzbot report, please reply with:
>>> #syz dup: exact-subject-of-another-report
>>> If it's a one-off invalid bug report, please reply with:
>>> #syz invalid
>>> Note: if the crash happens again, it will cause creation of a new bug
>>> report.
>>> Note: all commands must start from beginning of the line in the email body.
>>>
>>> --
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>>> For more options, visit https://groups.google.com/d/optout.
>>
>>
>> This looks like +rtnetlink issue.
>>
>
> Same with this one, perhaps related to / fixed by:
> http://patchwork.ozlabs.org/patch/850957/
>
Looking at the log, this one seems to be an infinite loop in SCTP code
with console output in it. Kernel is busy printing gazilion of:
[ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512
** 110 printk messages dropped **
[ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512
** 103 printk messages dropped **
...
[ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512
[ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512
[ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512
Looks like a different issue.
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: INFO: task hung in bpf_exit_net
2017-12-22 10:58 ` Dmitry Vyukov
@ 2017-12-22 11:16 ` Marcelo Ricardo Leitner
-1 siblings, 0 replies; 15+ messages in thread
From: Marcelo Ricardo Leitner @ 2017-12-22 11:16 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
> On Tue, Dec 19, 2017 at 7:20 PM, David Ahern <dsahern@gmail.com> wrote:
> > On 12/19/17 5:47 AM, Dmitry Vyukov wrote:
> >> On Tue, Dec 19, 2017 at 1:36 PM, syzbot
> >> <bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller.appspotmail.com>
> >> wrote:
> >>> Hello,
> >>>
> >>> syzkaller hit the following crash on
> >>> 7ceb97a071e80f1b5e4cd5a36de135612a836388
> >>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> >>> compiler: gcc (GCC) 7.1.1 20170620
> >>> .config is attached
> >>> Raw console output is attached.
> >>>
> >>> Unfortunately, I don't have any reproducer for this bug yet.
> >>>
> >>>
> >>> sctp: sctp_transport_update_pmtu: Reported pmtu 508 too low, using default
> >>> minimum of 512
> >>> INFO: task kworker/u4:0:5 blocked for more than 120 seconds.
> >>> Not tainted 4.15.0-rc2-next-20171205+ #59
> >>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> >>> kworker/u4:0 D15808 5 2 0x80000000
> >>> Workqueue: netns cleanup_net
> >>> Call Trace:
> >>> context_switch kernel/sched/core.c:2800 [inline]
> >>> __schedule+0x8eb/0x2060 kernel/sched/core.c:3376
> >>> schedule+0xf5/0x430 kernel/sched/core.c:3435
> >>> schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493
> >>> __mutex_lock_common kernel/locking/mutex.c:833 [inline]
> >>> __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
> >>> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
> >>> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
> >>> tc_action_net_exit include/net/act_api.h:125 [inline]
> >>> bpf_exit_net+0x1a2/0x340 net/sched/act_bpf.c:408
> >>> ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
> >>> cleanup_net+0x5c7/0xb60 net/core/net_namespace.c:484
> >>> process_one_work+0xbfd/0x1bc0 kernel/workqueue.c:2113
> >>> worker_thread+0x223/0x1990 kernel/workqueue.c:2247
> >>> kthread+0x37a/0x440 kernel/kthread.c:238
> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
> >>>
> >>> Showing all locks held in the system:
> >>> 4 locks held by kworker/u4:0/5:
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> __write_once_size include/linux/compiler.h:212 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_data kernel/workqueue.c:619 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
> >>> #1: (net_cleanup_work){+.+.}, at: [<000000006c7c48a3>]
> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
> >>> #2: (net_mutex){+.+.}, at: [<00000000bf4709f3>] cleanup_net+0x247/0xb60
> >>> net/core/net_namespace.c:450
> >>> #3: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
> >>> net/core/rtnetlink.c:74
> >>> 3 locks held by kworker/1:0/17:
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> __write_once_size include/linux/compiler.h:212 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_data kernel/workqueue.c:619 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
> >>> #1: ((addr_chk_work).work){+.+.}, at: [<000000006c7c48a3>]
> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
> >>> #2: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
> >>> net/core/rtnetlink.c:74
> >>> 2 locks held by khungtaskd/675:
> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>]
> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>] watchdog+0x1c5/0xd60
> >>> kernel/hung_task.c:249
> >>> #1: (tasklist_lock){.+.+}, at: [<000000005288685e>]
> >>> debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
> >>> 1 lock held by rsyslogd/2974:
> >>> #0: (&f->f_pos_lock){+.+.}, at: [<0000000011e00499>]
> >>> __fdget_pos+0x131/0x1a0 fs/file.c:770
> >>> 2 locks held by getty/3056:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3057:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3058:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3059:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3060:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3061:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3062:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>>
> >>> ======================> >>>
> >>> NMI backtrace for cpu 0
> >>> CPU: 0 PID: 675 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171205+ #59
> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >>> Google 01/01/2011
> >>> Call Trace:
> >>> __dump_stack lib/dump_stack.c:17 [inline]
> >>> dump_stack+0x194/0x257 lib/dump_stack.c:53
> >>> nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
> >>> nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
> >>> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
> >>> trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
> >>> check_hung_task kernel/hung_task.c:132 [inline]
> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
> >>> watchdog+0x90c/0xd60 kernel/hung_task.c:249
> >>> kthread+0x37a/0x440 kernel/kthread.c:238
> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
> >>> Sending NMI from CPU 0 to CPUs 1:
> >>> NMI backtrace for cpu 1
> >>> CPU: 1 PID: 13156 Comm: syz-executor7 Not tainted 4.15.0-rc2-next-20171205+
> >>> #59
> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >>> Google 01/01/2011
> >>> task: 000000005209c120 task.stack: 00000000ffaab0e8
> >>> RIP: 0010:inb arch/x86/include/asm/io.h:348 [inline]
> >>> RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:434
> >>> RSP: 0018:ffff8801c0a16e70 EFLAGS: 00000002
> >>> RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
> >>> RDX: 00000000000003fd RSI: ffffc90003745000 RDI: ffffffff87cf1a40
> >>> RBP: ffff8801c0a16e80 R08: 0000000000000005 R09: 000000000000000c
> >>> R10: 0000000000000000 R11: ffffffff8748dd20 R12: ffffffff87cf1a00
> >>> R13: 0000000000000020 R14: fffffbfff0f9e387 R15: fffffbfff0f9e34a
> >>> FS: 00007f6d52e3f700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
> >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >>> CR2: 000000c42005de80 CR3: 00000001c368a000 CR4: 00000000001406e0
> >>> DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
> >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
> >>> Call Trace:
> >>> serial_in drivers/tty/serial/8250/8250.h:111 [inline]
> >>> wait_for_xmitr+0x93/0x1e0 drivers/tty/serial/8250/8250_port.c:2033
> >>> serial8250_console_putchar+0x1f/0x60
> >>> drivers/tty/serial/8250/8250_port.c:3170
> >>> uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1858
> >>> serial8250_console_write+0x647/0xa20
> >>> drivers/tty/serial/8250/8250_port.c:3236
> >>> univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590
> >>> call_console_drivers kernel/printk/printk.c:1574 [inline]
> >>> console_unlock+0x788/0xd70 kernel/printk/printk.c:2233
> >>> vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757
> >>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
> >>> vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
> >>> printk+0xaa/0xca kernel/printk/printk.c:1829
> >>> nla_parse+0x374/0x3d0 lib/nlattr.c:257
> >>> nlmsg_parse include/net/netlink.h:398 [inline]
> >>> nl80211_dump_wiphy_parse.isra.37.constprop.83+0x138/0x5c0
> >>> net/wireless/nl80211.c:1920
> >>> nl80211_dump_interface+0x596/0x820 net/wireless/nl80211.c:2660
> >>> genl_lock_dumpit+0x68/0x90 net/netlink/genetlink.c:480
> >>> netlink_dump+0x48c/0xce0 net/netlink/af_netlink.c:2186
> >>> __netlink_dump_start+0x4f0/0x6d0 net/netlink/af_netlink.c:2283
> >>> genl_family_rcv_msg+0xd27/0xfc0 net/netlink/genetlink.c:548
> >>> genl_rcv_msg+0xb2/0x140 net/netlink/genetlink.c:624
> >>> netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2405
> >>> genl_rcv+0x28/0x40 net/netlink/genetlink.c:635
> >>> netlink_unicast_kernel net/netlink/af_netlink.c:1272 [inline]
> >>> netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1298
> >>> netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1861
> >>> sock_sendmsg_nosec net/socket.c:636 [inline]
> >>> sock_sendmsg+0xca/0x110 net/socket.c:646
> >>> sock_write_iter+0x320/0x5e0 net/socket.c:915
> >>> call_write_iter include/linux/fs.h:1776 [inline]
> >>> new_sync_write fs/read_write.c:469 [inline]
> >>> __vfs_write+0x68a/0x970 fs/read_write.c:482
> >>> vfs_write+0x18f/0x510 fs/read_write.c:544
> >>> SYSC_write fs/read_write.c:589 [inline]
> >>> SyS_write+0xef/0x220 fs/read_write.c:581
> >>> entry_SYSCALL_64_fastpath+0x1f/0x96
> >>> RIP: 0033:0x4529d9
> >>> RSP: 002b:00007f6d52e3ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
> >>> RAX: ffffffffffffffda RBX: 00007f6d52e3f700 RCX: 00000000004529d9
> >>> RDX: 0000000000000024 RSI: 0000000020454000 RDI: 0000000000000016
> >>> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> >>> R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
> >>> R13: 0000000000a6f7ff R14: 00007f6d52e3f9c0 R15: 0000000000000000
> >>> Code: 24 d9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa
> >>> 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 40 89 da ec <5b> 0f b6 c0 41
> >>> 5c 5d c3 e8 38 b0 18 ff eb c2 e8 91 b0 18 ff eb
> >>>
> >>>
> >>> ---
> >>> This bug is generated by a dumb bot. It may contain errors.
> >>> See https://goo.gl/tpsmEJ for details.
> >>> Direct all questions to syzkaller@googlegroups.com.
> >>> Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>
> >>>
> >>> syzbot will keep track of this bug report.
> >>> Once a fix for this bug is merged into any tree, reply to this email with:
> >>> #syz fix: exact-commit-title
> >>> To mark this as a duplicate of another syzbot report, please reply with:
> >>> #syz dup: exact-subject-of-another-report
> >>> If it's a one-off invalid bug report, please reply with:
> >>> #syz invalid
> >>> Note: if the crash happens again, it will cause creation of a new bug
> >>> report.
> >>> Note: all commands must start from beginning of the line in the email body.
> >>>
> >>> --
> >>> 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/001a1143fd00a8cc790560b0b552%40google.com.
> >>> For more options, visit https://groups.google.com/d/optout.
> >>
> >>
> >> This looks like +rtnetlink issue.
> >>
> >
> > Same with this one, perhaps related to / fixed by:
> > http://patchwork.ozlabs.org/patch/850957/
> >
>
>
>
> Looking at the log, this one seems to be an infinite loop in SCTP code
> with console output in it. Kernel is busy printing gazilion of:
Do you have a link for such log? I don't seem to have received the
initial syzbot email, so I don't have its attachments. Or if you may,
please fwd it to me/list.
Thanks.
>
> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 110 printk messages dropped **
> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 103 printk messages dropped **
> ...
> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
>
> Looks like a different issue.
>
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: INFO: task hung in bpf_exit_net
@ 2017-12-22 11:16 ` Marcelo Ricardo Leitner
0 siblings, 0 replies; 15+ messages in thread
From: Marcelo Ricardo Leitner @ 2017-12-22 11:16 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
> On Tue, Dec 19, 2017 at 7:20 PM, David Ahern <dsahern@gmail.com> wrote:
> > On 12/19/17 5:47 AM, Dmitry Vyukov wrote:
> >> On Tue, Dec 19, 2017 at 1:36 PM, syzbot
> >> <bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller.appspotmail.com>
> >> wrote:
> >>> Hello,
> >>>
> >>> syzkaller hit the following crash on
> >>> 7ceb97a071e80f1b5e4cd5a36de135612a836388
> >>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> >>> compiler: gcc (GCC) 7.1.1 20170620
> >>> .config is attached
> >>> Raw console output is attached.
> >>>
> >>> Unfortunately, I don't have any reproducer for this bug yet.
> >>>
> >>>
> >>> sctp: sctp_transport_update_pmtu: Reported pmtu 508 too low, using default
> >>> minimum of 512
> >>> INFO: task kworker/u4:0:5 blocked for more than 120 seconds.
> >>> Not tainted 4.15.0-rc2-next-20171205+ #59
> >>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> >>> kworker/u4:0 D15808 5 2 0x80000000
> >>> Workqueue: netns cleanup_net
> >>> Call Trace:
> >>> context_switch kernel/sched/core.c:2800 [inline]
> >>> __schedule+0x8eb/0x2060 kernel/sched/core.c:3376
> >>> schedule+0xf5/0x430 kernel/sched/core.c:3435
> >>> schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493
> >>> __mutex_lock_common kernel/locking/mutex.c:833 [inline]
> >>> __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
> >>> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
> >>> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
> >>> tc_action_net_exit include/net/act_api.h:125 [inline]
> >>> bpf_exit_net+0x1a2/0x340 net/sched/act_bpf.c:408
> >>> ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
> >>> cleanup_net+0x5c7/0xb60 net/core/net_namespace.c:484
> >>> process_one_work+0xbfd/0x1bc0 kernel/workqueue.c:2113
> >>> worker_thread+0x223/0x1990 kernel/workqueue.c:2247
> >>> kthread+0x37a/0x440 kernel/kthread.c:238
> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
> >>>
> >>> Showing all locks held in the system:
> >>> 4 locks held by kworker/u4:0/5:
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> __write_once_size include/linux/compiler.h:212 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_data kernel/workqueue.c:619 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
> >>> #1: (net_cleanup_work){+.+.}, at: [<000000006c7c48a3>]
> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
> >>> #2: (net_mutex){+.+.}, at: [<00000000bf4709f3>] cleanup_net+0x247/0xb60
> >>> net/core/net_namespace.c:450
> >>> #3: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
> >>> net/core/rtnetlink.c:74
> >>> 3 locks held by kworker/1:0/17:
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> __write_once_size include/linux/compiler.h:212 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_data kernel/workqueue.c:619 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
> >>> #1: ((addr_chk_work).work){+.+.}, at: [<000000006c7c48a3>]
> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
> >>> #2: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
> >>> net/core/rtnetlink.c:74
> >>> 2 locks held by khungtaskd/675:
> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>]
> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>] watchdog+0x1c5/0xd60
> >>> kernel/hung_task.c:249
> >>> #1: (tasklist_lock){.+.+}, at: [<000000005288685e>]
> >>> debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
> >>> 1 lock held by rsyslogd/2974:
> >>> #0: (&f->f_pos_lock){+.+.}, at: [<0000000011e00499>]
> >>> __fdget_pos+0x131/0x1a0 fs/file.c:770
> >>> 2 locks held by getty/3056:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3057:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3058:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3059:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3060:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3061:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>> 2 locks held by getty/3062:
> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> >>>
> >>> =============================================
> >>>
> >>> NMI backtrace for cpu 0
> >>> CPU: 0 PID: 675 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171205+ #59
> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >>> Google 01/01/2011
> >>> Call Trace:
> >>> __dump_stack lib/dump_stack.c:17 [inline]
> >>> dump_stack+0x194/0x257 lib/dump_stack.c:53
> >>> nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
> >>> nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
> >>> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
> >>> trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
> >>> check_hung_task kernel/hung_task.c:132 [inline]
> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
> >>> watchdog+0x90c/0xd60 kernel/hung_task.c:249
> >>> kthread+0x37a/0x440 kernel/kthread.c:238
> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
> >>> Sending NMI from CPU 0 to CPUs 1:
> >>> NMI backtrace for cpu 1
> >>> CPU: 1 PID: 13156 Comm: syz-executor7 Not tainted 4.15.0-rc2-next-20171205+
> >>> #59
> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >>> Google 01/01/2011
> >>> task: 000000005209c120 task.stack: 00000000ffaab0e8
> >>> RIP: 0010:inb arch/x86/include/asm/io.h:348 [inline]
> >>> RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:434
> >>> RSP: 0018:ffff8801c0a16e70 EFLAGS: 00000002
> >>> RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
> >>> RDX: 00000000000003fd RSI: ffffc90003745000 RDI: ffffffff87cf1a40
> >>> RBP: ffff8801c0a16e80 R08: 0000000000000005 R09: 000000000000000c
> >>> R10: 0000000000000000 R11: ffffffff8748dd20 R12: ffffffff87cf1a00
> >>> R13: 0000000000000020 R14: fffffbfff0f9e387 R15: fffffbfff0f9e34a
> >>> FS: 00007f6d52e3f700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
> >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >>> CR2: 000000c42005de80 CR3: 00000001c368a000 CR4: 00000000001406e0
> >>> DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
> >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
> >>> Call Trace:
> >>> serial_in drivers/tty/serial/8250/8250.h:111 [inline]
> >>> wait_for_xmitr+0x93/0x1e0 drivers/tty/serial/8250/8250_port.c:2033
> >>> serial8250_console_putchar+0x1f/0x60
> >>> drivers/tty/serial/8250/8250_port.c:3170
> >>> uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1858
> >>> serial8250_console_write+0x647/0xa20
> >>> drivers/tty/serial/8250/8250_port.c:3236
> >>> univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590
> >>> call_console_drivers kernel/printk/printk.c:1574 [inline]
> >>> console_unlock+0x788/0xd70 kernel/printk/printk.c:2233
> >>> vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757
> >>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
> >>> vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
> >>> printk+0xaa/0xca kernel/printk/printk.c:1829
> >>> nla_parse+0x374/0x3d0 lib/nlattr.c:257
> >>> nlmsg_parse include/net/netlink.h:398 [inline]
> >>> nl80211_dump_wiphy_parse.isra.37.constprop.83+0x138/0x5c0
> >>> net/wireless/nl80211.c:1920
> >>> nl80211_dump_interface+0x596/0x820 net/wireless/nl80211.c:2660
> >>> genl_lock_dumpit+0x68/0x90 net/netlink/genetlink.c:480
> >>> netlink_dump+0x48c/0xce0 net/netlink/af_netlink.c:2186
> >>> __netlink_dump_start+0x4f0/0x6d0 net/netlink/af_netlink.c:2283
> >>> genl_family_rcv_msg+0xd27/0xfc0 net/netlink/genetlink.c:548
> >>> genl_rcv_msg+0xb2/0x140 net/netlink/genetlink.c:624
> >>> netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2405
> >>> genl_rcv+0x28/0x40 net/netlink/genetlink.c:635
> >>> netlink_unicast_kernel net/netlink/af_netlink.c:1272 [inline]
> >>> netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1298
> >>> netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1861
> >>> sock_sendmsg_nosec net/socket.c:636 [inline]
> >>> sock_sendmsg+0xca/0x110 net/socket.c:646
> >>> sock_write_iter+0x320/0x5e0 net/socket.c:915
> >>> call_write_iter include/linux/fs.h:1776 [inline]
> >>> new_sync_write fs/read_write.c:469 [inline]
> >>> __vfs_write+0x68a/0x970 fs/read_write.c:482
> >>> vfs_write+0x18f/0x510 fs/read_write.c:544
> >>> SYSC_write fs/read_write.c:589 [inline]
> >>> SyS_write+0xef/0x220 fs/read_write.c:581
> >>> entry_SYSCALL_64_fastpath+0x1f/0x96
> >>> RIP: 0033:0x4529d9
> >>> RSP: 002b:00007f6d52e3ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
> >>> RAX: ffffffffffffffda RBX: 00007f6d52e3f700 RCX: 00000000004529d9
> >>> RDX: 0000000000000024 RSI: 0000000020454000 RDI: 0000000000000016
> >>> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> >>> R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
> >>> R13: 0000000000a6f7ff R14: 00007f6d52e3f9c0 R15: 0000000000000000
> >>> Code: 24 d9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa
> >>> 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 40 89 da ec <5b> 0f b6 c0 41
> >>> 5c 5d c3 e8 38 b0 18 ff eb c2 e8 91 b0 18 ff eb
> >>>
> >>>
> >>> ---
> >>> This bug is generated by a dumb bot. It may contain errors.
> >>> See https://goo.gl/tpsmEJ for details.
> >>> Direct all questions to syzkaller@googlegroups.com.
> >>> Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>
> >>>
> >>> syzbot will keep track of this bug report.
> >>> Once a fix for this bug is merged into any tree, reply to this email with:
> >>> #syz fix: exact-commit-title
> >>> To mark this as a duplicate of another syzbot report, please reply with:
> >>> #syz dup: exact-subject-of-another-report
> >>> If it's a one-off invalid bug report, please reply with:
> >>> #syz invalid
> >>> Note: if the crash happens again, it will cause creation of a new bug
> >>> report.
> >>> Note: all commands must start from beginning of the line in the email body.
> >>>
> >>> --
> >>> 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/001a1143fd00a8cc790560b0b552%40google.com.
> >>> For more options, visit https://groups.google.com/d/optout.
> >>
> >>
> >> This looks like +rtnetlink issue.
> >>
> >
> > Same with this one, perhaps related to / fixed by:
> > http://patchwork.ozlabs.org/patch/850957/
> >
>
>
>
> Looking at the log, this one seems to be an infinite loop in SCTP code
> with console output in it. Kernel is busy printing gazilion of:
Do you have a link for such log? I don't seem to have received the
initial syzbot email, so I don't have its attachments. Or if you may,
please fwd it to me/list.
Thanks.
>
> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 110 printk messages dropped **
> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 103 printk messages dropped **
> ...
> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
>
> Looks like a different issue.
>
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: INFO: task hung in bpf_exit_net
2017-12-22 11:16 ` Marcelo Ricardo Leitner
@ 2017-12-22 11:24 ` Dmitry Vyukov
-1 siblings, 0 replies; 15+ messages in thread
From: Dmitry Vyukov @ 2017-12-22 11:24 UTC (permalink / raw)
To: Marcelo Ricardo Leitner
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 12:16 PM, Marcelo Ricardo Leitner
<marcelo.leitner@gmail.com> wrote:
> On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
>> On Tue, Dec 19, 2017 at 7:20 PM, David Ahern <dsahern@gmail.com> wrote:
>> > On 12/19/17 5:47 AM, Dmitry Vyukov wrote:
>> >> On Tue, Dec 19, 2017 at 1:36 PM, syzbot
>> >> <bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller.appspotmail.com>
>> >> wrote:
>> >>> Hello,
>> >>>
>> >>> syzkaller hit the following crash on
>> >>> 7ceb97a071e80f1b5e4cd5a36de135612a836388
>> >>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
>> >>> compiler: gcc (GCC) 7.1.1 20170620
>> >>> .config is attached
>> >>> Raw console output is attached.
>> >>>
>> >>> Unfortunately, I don't have any reproducer for this bug yet.
>> >>>
>> >>>
>> >>> sctp: sctp_transport_update_pmtu: Reported pmtu 508 too low, using default
>> >>> minimum of 512
>> >>> INFO: task kworker/u4:0:5 blocked for more than 120 seconds.
>> >>> Not tainted 4.15.0-rc2-next-20171205+ #59
>> >>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> >>> kworker/u4:0 D15808 5 2 0x80000000
>> >>> Workqueue: netns cleanup_net
>> >>> Call Trace:
>> >>> context_switch kernel/sched/core.c:2800 [inline]
>> >>> __schedule+0x8eb/0x2060 kernel/sched/core.c:3376
>> >>> schedule+0xf5/0x430 kernel/sched/core.c:3435
>> >>> schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493
>> >>> __mutex_lock_common kernel/locking/mutex.c:833 [inline]
>> >>> __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
>> >>> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
>> >>> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
>> >>> tc_action_net_exit include/net/act_api.h:125 [inline]
>> >>> bpf_exit_net+0x1a2/0x340 net/sched/act_bpf.c:408
>> >>> ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
>> >>> cleanup_net+0x5c7/0xb60 net/core/net_namespace.c:484
>> >>> process_one_work+0xbfd/0x1bc0 kernel/workqueue.c:2113
>> >>> worker_thread+0x223/0x1990 kernel/workqueue.c:2247
>> >>> kthread+0x37a/0x440 kernel/kthread.c:238
>> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
>> >>>
>> >>> Showing all locks held in the system:
>> >>> 4 locks held by kworker/u4:0/5:
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> __write_once_size include/linux/compiler.h:212 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_data kernel/workqueue.c:619 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
>> >>> #1: (net_cleanup_work){+.+.}, at: [<000000006c7c48a3>]
>> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
>> >>> #2: (net_mutex){+.+.}, at: [<00000000bf4709f3>] cleanup_net+0x247/0xb60
>> >>> net/core/net_namespace.c:450
>> >>> #3: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
>> >>> net/core/rtnetlink.c:74
>> >>> 3 locks held by kworker/1:0/17:
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> __write_once_size include/linux/compiler.h:212 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_data kernel/workqueue.c:619 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
>> >>> #1: ((addr_chk_work).work){+.+.}, at: [<000000006c7c48a3>]
>> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
>> >>> #2: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
>> >>> net/core/rtnetlink.c:74
>> >>> 2 locks held by khungtaskd/675:
>> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>]
>> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
>> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>] watchdog+0x1c5/0xd60
>> >>> kernel/hung_task.c:249
>> >>> #1: (tasklist_lock){.+.+}, at: [<000000005288685e>]
>> >>> debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
>> >>> 1 lock held by rsyslogd/2974:
>> >>> #0: (&f->f_pos_lock){+.+.}, at: [<0000000011e00499>]
>> >>> __fdget_pos+0x131/0x1a0 fs/file.c:770
>> >>> 2 locks held by getty/3056:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3057:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3058:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3059:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3060:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3061:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3062:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>>
>> >>> ======================>> >>>
>> >>> NMI backtrace for cpu 0
>> >>> CPU: 0 PID: 675 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171205+ #59
>> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> >>> Google 01/01/2011
>> >>> Call Trace:
>> >>> __dump_stack lib/dump_stack.c:17 [inline]
>> >>> dump_stack+0x194/0x257 lib/dump_stack.c:53
>> >>> nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
>> >>> nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
>> >>> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
>> >>> trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
>> >>> check_hung_task kernel/hung_task.c:132 [inline]
>> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
>> >>> watchdog+0x90c/0xd60 kernel/hung_task.c:249
>> >>> kthread+0x37a/0x440 kernel/kthread.c:238
>> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
>> >>> Sending NMI from CPU 0 to CPUs 1:
>> >>> NMI backtrace for cpu 1
>> >>> CPU: 1 PID: 13156 Comm: syz-executor7 Not tainted 4.15.0-rc2-next-20171205+
>> >>> #59
>> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> >>> Google 01/01/2011
>> >>> task: 000000005209c120 task.stack: 00000000ffaab0e8
>> >>> RIP: 0010:inb arch/x86/include/asm/io.h:348 [inline]
>> >>> RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:434
>> >>> RSP: 0018:ffff8801c0a16e70 EFLAGS: 00000002
>> >>> RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
>> >>> RDX: 00000000000003fd RSI: ffffc90003745000 RDI: ffffffff87cf1a40
>> >>> RBP: ffff8801c0a16e80 R08: 0000000000000005 R09: 000000000000000c
>> >>> R10: 0000000000000000 R11: ffffffff8748dd20 R12: ffffffff87cf1a00
>> >>> R13: 0000000000000020 R14: fffffbfff0f9e387 R15: fffffbfff0f9e34a
>> >>> FS: 00007f6d52e3f700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
>> >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> >>> CR2: 000000c42005de80 CR3: 00000001c368a000 CR4: 00000000001406e0
>> >>> DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
>> >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
>> >>> Call Trace:
>> >>> serial_in drivers/tty/serial/8250/8250.h:111 [inline]
>> >>> wait_for_xmitr+0x93/0x1e0 drivers/tty/serial/8250/8250_port.c:2033
>> >>> serial8250_console_putchar+0x1f/0x60
>> >>> drivers/tty/serial/8250/8250_port.c:3170
>> >>> uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1858
>> >>> serial8250_console_write+0x647/0xa20
>> >>> drivers/tty/serial/8250/8250_port.c:3236
>> >>> univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590
>> >>> call_console_drivers kernel/printk/printk.c:1574 [inline]
>> >>> console_unlock+0x788/0xd70 kernel/printk/printk.c:2233
>> >>> vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757
>> >>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
>> >>> vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
>> >>> printk+0xaa/0xca kernel/printk/printk.c:1829
>> >>> nla_parse+0x374/0x3d0 lib/nlattr.c:257
>> >>> nlmsg_parse include/net/netlink.h:398 [inline]
>> >>> nl80211_dump_wiphy_parse.isra.37.constprop.83+0x138/0x5c0
>> >>> net/wireless/nl80211.c:1920
>> >>> nl80211_dump_interface+0x596/0x820 net/wireless/nl80211.c:2660
>> >>> genl_lock_dumpit+0x68/0x90 net/netlink/genetlink.c:480
>> >>> netlink_dump+0x48c/0xce0 net/netlink/af_netlink.c:2186
>> >>> __netlink_dump_start+0x4f0/0x6d0 net/netlink/af_netlink.c:2283
>> >>> genl_family_rcv_msg+0xd27/0xfc0 net/netlink/genetlink.c:548
>> >>> genl_rcv_msg+0xb2/0x140 net/netlink/genetlink.c:624
>> >>> netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2405
>> >>> genl_rcv+0x28/0x40 net/netlink/genetlink.c:635
>> >>> netlink_unicast_kernel net/netlink/af_netlink.c:1272 [inline]
>> >>> netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1298
>> >>> netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1861
>> >>> sock_sendmsg_nosec net/socket.c:636 [inline]
>> >>> sock_sendmsg+0xca/0x110 net/socket.c:646
>> >>> sock_write_iter+0x320/0x5e0 net/socket.c:915
>> >>> call_write_iter include/linux/fs.h:1776 [inline]
>> >>> new_sync_write fs/read_write.c:469 [inline]
>> >>> __vfs_write+0x68a/0x970 fs/read_write.c:482
>> >>> vfs_write+0x18f/0x510 fs/read_write.c:544
>> >>> SYSC_write fs/read_write.c:589 [inline]
>> >>> SyS_write+0xef/0x220 fs/read_write.c:581
>> >>> entry_SYSCALL_64_fastpath+0x1f/0x96
>> >>> RIP: 0033:0x4529d9
>> >>> RSP: 002b:00007f6d52e3ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
>> >>> RAX: ffffffffffffffda RBX: 00007f6d52e3f700 RCX: 00000000004529d9
>> >>> RDX: 0000000000000024 RSI: 0000000020454000 RDI: 0000000000000016
>> >>> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
>> >>> R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
>> >>> R13: 0000000000a6f7ff R14: 00007f6d52e3f9c0 R15: 0000000000000000
>> >>> Code: 24 d9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa
>> >>> 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 40 89 da ec <5b> 0f b6 c0 41
>> >>> 5c 5d c3 e8 38 b0 18 ff eb c2 e8 91 b0 18 ff eb
>> >>>
>> >>>
>> >>> ---
>> >>> This bug is generated by a dumb bot. It may contain errors.
>> >>> See https://goo.gl/tpsmEJ for details.
>> >>> Direct all questions to syzkaller@googlegroups.com.
>> >>> Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>
>> >>>
>> >>> syzbot will keep track of this bug report.
>> >>> Once a fix for this bug is merged into any tree, reply to this email with:
>> >>> #syz fix: exact-commit-title
>> >>> To mark this as a duplicate of another syzbot report, please reply with:
>> >>> #syz dup: exact-subject-of-another-report
>> >>> If it's a one-off invalid bug report, please reply with:
>> >>> #syz invalid
>> >>> Note: if the crash happens again, it will cause creation of a new bug
>> >>> report.
>> >>> Note: all commands must start from beginning of the line in the email body.
>> >>>
>> >>> --
>> >>> 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/001a1143fd00a8cc790560b0b552%40google.com.
>> >>> For more options, visit https://groups.google.com/d/optout.
>> >>
>> >>
>> >> This looks like +rtnetlink issue.
>> >>
>> >
>> > Same with this one, perhaps related to / fixed by:
>> > http://patchwork.ozlabs.org/patch/850957/
>> >
>>
>>
>>
>> Looking at the log, this one seems to be an infinite loop in SCTP code
>> with console output in it. Kernel is busy printing gazilion of:
>
> Do you have a link for such log? I don't seem to have received the
> initial syzbot email, so I don't have its attachments. Or if you may,
> please fwd it to me/list.
https://groups.google.com/forum/#!searchin/syzkaller-bugs/%22INFO$3A$20task$20hung$20in$20bpf_exit_net%22%7Csort:date
> Thanks.
>
>>
>> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> ** 110 printk messages dropped **
>> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> ** 103 printk messages dropped **
>> ...
>> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>>
>> Looks like a different issue.
>>
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: INFO: task hung in bpf_exit_net
@ 2017-12-22 11:24 ` Dmitry Vyukov
0 siblings, 0 replies; 15+ messages in thread
From: Dmitry Vyukov @ 2017-12-22 11:24 UTC (permalink / raw)
To: Marcelo Ricardo Leitner
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 12:16 PM, Marcelo Ricardo Leitner
<marcelo.leitner@gmail.com> wrote:
> On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
>> On Tue, Dec 19, 2017 at 7:20 PM, David Ahern <dsahern@gmail.com> wrote:
>> > On 12/19/17 5:47 AM, Dmitry Vyukov wrote:
>> >> On Tue, Dec 19, 2017 at 1:36 PM, syzbot
>> >> <bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller.appspotmail.com>
>> >> wrote:
>> >>> Hello,
>> >>>
>> >>> syzkaller hit the following crash on
>> >>> 7ceb97a071e80f1b5e4cd5a36de135612a836388
>> >>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
>> >>> compiler: gcc (GCC) 7.1.1 20170620
>> >>> .config is attached
>> >>> Raw console output is attached.
>> >>>
>> >>> Unfortunately, I don't have any reproducer for this bug yet.
>> >>>
>> >>>
>> >>> sctp: sctp_transport_update_pmtu: Reported pmtu 508 too low, using default
>> >>> minimum of 512
>> >>> INFO: task kworker/u4:0:5 blocked for more than 120 seconds.
>> >>> Not tainted 4.15.0-rc2-next-20171205+ #59
>> >>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> >>> kworker/u4:0 D15808 5 2 0x80000000
>> >>> Workqueue: netns cleanup_net
>> >>> Call Trace:
>> >>> context_switch kernel/sched/core.c:2800 [inline]
>> >>> __schedule+0x8eb/0x2060 kernel/sched/core.c:3376
>> >>> schedule+0xf5/0x430 kernel/sched/core.c:3435
>> >>> schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493
>> >>> __mutex_lock_common kernel/locking/mutex.c:833 [inline]
>> >>> __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
>> >>> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
>> >>> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
>> >>> tc_action_net_exit include/net/act_api.h:125 [inline]
>> >>> bpf_exit_net+0x1a2/0x340 net/sched/act_bpf.c:408
>> >>> ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
>> >>> cleanup_net+0x5c7/0xb60 net/core/net_namespace.c:484
>> >>> process_one_work+0xbfd/0x1bc0 kernel/workqueue.c:2113
>> >>> worker_thread+0x223/0x1990 kernel/workqueue.c:2247
>> >>> kthread+0x37a/0x440 kernel/kthread.c:238
>> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
>> >>>
>> >>> Showing all locks held in the system:
>> >>> 4 locks held by kworker/u4:0/5:
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> __write_once_size include/linux/compiler.h:212 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_data kernel/workqueue.c:619 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
>> >>> #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000b9f061a2>]
>> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
>> >>> #1: (net_cleanup_work){+.+.}, at: [<000000006c7c48a3>]
>> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
>> >>> #2: (net_mutex){+.+.}, at: [<00000000bf4709f3>] cleanup_net+0x247/0xb60
>> >>> net/core/net_namespace.c:450
>> >>> #3: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
>> >>> net/core/rtnetlink.c:74
>> >>> 3 locks held by kworker/1:0/17:
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> __write_once_size include/linux/compiler.h:212 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_data kernel/workqueue.c:619 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
>> >>> #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000b9f061a2>]
>> >>> process_one_work+0xad4/0x1bc0 kernel/workqueue.c:2084
>> >>> #1: ((addr_chk_work).work){+.+.}, at: [<000000006c7c48a3>]
>> >>> process_one_work+0xb2f/0x1bc0 kernel/workqueue.c:2088
>> >>> #2: (rtnl_mutex){+.+.}, at: [<0000000053390f0b>] rtnl_lock+0x17/0x20
>> >>> net/core/rtnetlink.c:74
>> >>> 2 locks held by khungtaskd/675:
>> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>]
>> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
>> >>> #0: (rcu_read_lock){....}, at: [<00000000587c8471>] watchdog+0x1c5/0xd60
>> >>> kernel/hung_task.c:249
>> >>> #1: (tasklist_lock){.+.+}, at: [<000000005288685e>]
>> >>> debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
>> >>> 1 lock held by rsyslogd/2974:
>> >>> #0: (&f->f_pos_lock){+.+.}, at: [<0000000011e00499>]
>> >>> __fdget_pos+0x131/0x1a0 fs/file.c:770
>> >>> 2 locks held by getty/3056:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3057:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3058:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3059:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3060:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3061:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>> 2 locks held by getty/3062:
>> >>> #0: (&tty->ldisc_sem){++++}, at: [<00000000b9fd70a9>]
>> >>> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>> >>> #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000abb3bd08>]
>> >>> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
>> >>>
>> >>> =============================================
>> >>>
>> >>> NMI backtrace for cpu 0
>> >>> CPU: 0 PID: 675 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171205+ #59
>> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> >>> Google 01/01/2011
>> >>> Call Trace:
>> >>> __dump_stack lib/dump_stack.c:17 [inline]
>> >>> dump_stack+0x194/0x257 lib/dump_stack.c:53
>> >>> nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
>> >>> nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
>> >>> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
>> >>> trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
>> >>> check_hung_task kernel/hung_task.c:132 [inline]
>> >>> check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
>> >>> watchdog+0x90c/0xd60 kernel/hung_task.c:249
>> >>> kthread+0x37a/0x440 kernel/kthread.c:238
>> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517
>> >>> Sending NMI from CPU 0 to CPUs 1:
>> >>> NMI backtrace for cpu 1
>> >>> CPU: 1 PID: 13156 Comm: syz-executor7 Not tainted 4.15.0-rc2-next-20171205+
>> >>> #59
>> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> >>> Google 01/01/2011
>> >>> task: 000000005209c120 task.stack: 00000000ffaab0e8
>> >>> RIP: 0010:inb arch/x86/include/asm/io.h:348 [inline]
>> >>> RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:434
>> >>> RSP: 0018:ffff8801c0a16e70 EFLAGS: 00000002
>> >>> RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
>> >>> RDX: 00000000000003fd RSI: ffffc90003745000 RDI: ffffffff87cf1a40
>> >>> RBP: ffff8801c0a16e80 R08: 0000000000000005 R09: 000000000000000c
>> >>> R10: 0000000000000000 R11: ffffffff8748dd20 R12: ffffffff87cf1a00
>> >>> R13: 0000000000000020 R14: fffffbfff0f9e387 R15: fffffbfff0f9e34a
>> >>> FS: 00007f6d52e3f700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
>> >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> >>> CR2: 000000c42005de80 CR3: 00000001c368a000 CR4: 00000000001406e0
>> >>> DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
>> >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
>> >>> Call Trace:
>> >>> serial_in drivers/tty/serial/8250/8250.h:111 [inline]
>> >>> wait_for_xmitr+0x93/0x1e0 drivers/tty/serial/8250/8250_port.c:2033
>> >>> serial8250_console_putchar+0x1f/0x60
>> >>> drivers/tty/serial/8250/8250_port.c:3170
>> >>> uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1858
>> >>> serial8250_console_write+0x647/0xa20
>> >>> drivers/tty/serial/8250/8250_port.c:3236
>> >>> univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590
>> >>> call_console_drivers kernel/printk/printk.c:1574 [inline]
>> >>> console_unlock+0x788/0xd70 kernel/printk/printk.c:2233
>> >>> vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757
>> >>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
>> >>> vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
>> >>> printk+0xaa/0xca kernel/printk/printk.c:1829
>> >>> nla_parse+0x374/0x3d0 lib/nlattr.c:257
>> >>> nlmsg_parse include/net/netlink.h:398 [inline]
>> >>> nl80211_dump_wiphy_parse.isra.37.constprop.83+0x138/0x5c0
>> >>> net/wireless/nl80211.c:1920
>> >>> nl80211_dump_interface+0x596/0x820 net/wireless/nl80211.c:2660
>> >>> genl_lock_dumpit+0x68/0x90 net/netlink/genetlink.c:480
>> >>> netlink_dump+0x48c/0xce0 net/netlink/af_netlink.c:2186
>> >>> __netlink_dump_start+0x4f0/0x6d0 net/netlink/af_netlink.c:2283
>> >>> genl_family_rcv_msg+0xd27/0xfc0 net/netlink/genetlink.c:548
>> >>> genl_rcv_msg+0xb2/0x140 net/netlink/genetlink.c:624
>> >>> netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2405
>> >>> genl_rcv+0x28/0x40 net/netlink/genetlink.c:635
>> >>> netlink_unicast_kernel net/netlink/af_netlink.c:1272 [inline]
>> >>> netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1298
>> >>> netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1861
>> >>> sock_sendmsg_nosec net/socket.c:636 [inline]
>> >>> sock_sendmsg+0xca/0x110 net/socket.c:646
>> >>> sock_write_iter+0x320/0x5e0 net/socket.c:915
>> >>> call_write_iter include/linux/fs.h:1776 [inline]
>> >>> new_sync_write fs/read_write.c:469 [inline]
>> >>> __vfs_write+0x68a/0x970 fs/read_write.c:482
>> >>> vfs_write+0x18f/0x510 fs/read_write.c:544
>> >>> SYSC_write fs/read_write.c:589 [inline]
>> >>> SyS_write+0xef/0x220 fs/read_write.c:581
>> >>> entry_SYSCALL_64_fastpath+0x1f/0x96
>> >>> RIP: 0033:0x4529d9
>> >>> RSP: 002b:00007f6d52e3ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
>> >>> RAX: ffffffffffffffda RBX: 00007f6d52e3f700 RCX: 00000000004529d9
>> >>> RDX: 0000000000000024 RSI: 0000000020454000 RDI: 0000000000000016
>> >>> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
>> >>> R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
>> >>> R13: 0000000000a6f7ff R14: 00007f6d52e3f9c0 R15: 0000000000000000
>> >>> Code: 24 d9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa
>> >>> 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 40 89 da ec <5b> 0f b6 c0 41
>> >>> 5c 5d c3 e8 38 b0 18 ff eb c2 e8 91 b0 18 ff eb
>> >>>
>> >>>
>> >>> ---
>> >>> This bug is generated by a dumb bot. It may contain errors.
>> >>> See https://goo.gl/tpsmEJ for details.
>> >>> Direct all questions to syzkaller@googlegroups.com.
>> >>> Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>
>> >>>
>> >>> syzbot will keep track of this bug report.
>> >>> Once a fix for this bug is merged into any tree, reply to this email with:
>> >>> #syz fix: exact-commit-title
>> >>> To mark this as a duplicate of another syzbot report, please reply with:
>> >>> #syz dup: exact-subject-of-another-report
>> >>> If it's a one-off invalid bug report, please reply with:
>> >>> #syz invalid
>> >>> Note: if the crash happens again, it will cause creation of a new bug
>> >>> report.
>> >>> Note: all commands must start from beginning of the line in the email body.
>> >>>
>> >>> --
>> >>> 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/001a1143fd00a8cc790560b0b552%40google.com.
>> >>> For more options, visit https://groups.google.com/d/optout.
>> >>
>> >>
>> >> This looks like +rtnetlink issue.
>> >>
>> >
>> > Same with this one, perhaps related to / fixed by:
>> > http://patchwork.ozlabs.org/patch/850957/
>> >
>>
>>
>>
>> Looking at the log, this one seems to be an infinite loop in SCTP code
>> with console output in it. Kernel is busy printing gazilion of:
>
> Do you have a link for such log? I don't seem to have received the
> initial syzbot email, so I don't have its attachments. Or if you may,
> please fwd it to me/list.
https://groups.google.com/forum/#!searchin/syzkaller-bugs/%22INFO$3A$20task$20hung$20in$20bpf_exit_net%22%7Csort:date
> Thanks.
>
>>
>> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> ** 110 printk messages dropped **
>> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> ** 103 printk messages dropped **
>> ...
>> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
>> low, using default minimum of 512
>>
>> Looks like a different issue.
>>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: INFO: task hung in bpf_exit_net
2017-12-22 10:58 ` Dmitry Vyukov
@ 2017-12-22 18:28 ` Marcelo Ricardo Leitner
-1 siblings, 0 replies; 15+ messages in thread
From: Marcelo Ricardo Leitner @ 2017-12-22 18:28 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
...
> > Same with this one, perhaps related to / fixed by:
> > http://patchwork.ozlabs.org/patch/850957/
> >
>
>
>
> Looking at the log, this one seems to be an infinite loop in SCTP code
> with console output in it. Kernel is busy printing gazilion of:
>
> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 110 printk messages dropped **
> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 103 printk messages dropped **
> ...
> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
>
> Looks like a different issue.
>
Oh. I guess this is caused by the interface having a MTU smaller than
SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
(sctp_icmp_frag_needed) will trigger an instant retransmission.
But as the MTU is smaller, SCTP won't update it, but will issue the
retransmission anyway.
I will test this soon. Should be fairly easy to trigger it.
Marcelo
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: INFO: task hung in bpf_exit_net
@ 2017-12-22 18:28 ` Marcelo Ricardo Leitner
0 siblings, 0 replies; 15+ messages in thread
From: Marcelo Ricardo Leitner @ 2017-12-22 18:28 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
...
> > Same with this one, perhaps related to / fixed by:
> > http://patchwork.ozlabs.org/patch/850957/
> >
>
>
>
> Looking at the log, this one seems to be an infinite loop in SCTP code
> with console output in it. Kernel is busy printing gazilion of:
>
> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 110 printk messages dropped **
> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 103 printk messages dropped **
> ...
> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
>
> Looks like a different issue.
>
Oh. I guess this is caused by the interface having a MTU smaller than
SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
(sctp_icmp_frag_needed) will trigger an instant retransmission.
But as the MTU is smaller, SCTP won't update it, but will issue the
retransmission anyway.
I will test this soon. Should be fairly easy to trigger it.
Marcelo
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: INFO: task hung in bpf_exit_net
2017-12-22 18:28 ` Marcelo Ricardo Leitner
@ 2017-12-22 19:04 ` Marcelo Ricardo Leitner
-1 siblings, 0 replies; 15+ messages in thread
From: Marcelo Ricardo Leitner @ 2017-12-22 19:04 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 04:28:07PM -0200, Marcelo Ricardo Leitner wrote:
> On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
> ...
> > > Same with this one, perhaps related to / fixed by:
> > > http://patchwork.ozlabs.org/patch/850957/
> > >
> >
> >
> >
> > Looking at the log, this one seems to be an infinite loop in SCTP code
> > with console output in it. Kernel is busy printing gazilion of:
> >
> > [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > ** 110 printk messages dropped **
> > [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > ** 103 printk messages dropped **
> > ...
> > [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> >
> > Looks like a different issue.
> >
>
> Oh. I guess this is caused by the interface having a MTU smaller than
> SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
> (sctp_icmp_frag_needed) will trigger an instant retransmission.
> But as the MTU is smaller, SCTP won't update it, but will issue the
> retransmission anyway.
>
> I will test this soon. Should be fairly easy to trigger it.
Reproduced it.
netns A veth0(1500) - veth1(1500) B veth2(508) - veth3(508) C
When A sends a sctp packet bigger than 508, it triggers the issue as B
will reply a icmp frag needed with a size that sctp won't accept but
will retransmit anyway.
Marcelo
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: INFO: task hung in bpf_exit_net
@ 2017-12-22 19:04 ` Marcelo Ricardo Leitner
0 siblings, 0 replies; 15+ messages in thread
From: Marcelo Ricardo Leitner @ 2017-12-22 19:04 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: David Ahern, syzbot, LKML, Ingo Molnar, Peter Zijlstra,
syzkaller-bugs, David Miller, Florian Westphal, Daniel Borkmann,
Xin Long, jakub.kicinski, mschiffer, Vladislav Yasevich,
Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 04:28:07PM -0200, Marcelo Ricardo Leitner wrote:
> On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
> ...
> > > Same with this one, perhaps related to / fixed by:
> > > http://patchwork.ozlabs.org/patch/850957/
> > >
> >
> >
> >
> > Looking at the log, this one seems to be an infinite loop in SCTP code
> > with console output in it. Kernel is busy printing gazilion of:
> >
> > [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > ** 110 printk messages dropped **
> > [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > ** 103 printk messages dropped **
> > ...
> > [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> > [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > low, using default minimum of 512
> >
> > Looks like a different issue.
> >
>
> Oh. I guess this is caused by the interface having a MTU smaller than
> SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
> (sctp_icmp_frag_needed) will trigger an instant retransmission.
> But as the MTU is smaller, SCTP won't update it, but will issue the
> retransmission anyway.
>
> I will test this soon. Should be fairly easy to trigger it.
Reproduced it.
netns A veth0(1500) - veth1(1500) B veth2(508) - veth3(508) C
When A sends a sctp packet bigger than 508, it triggers the issue as B
will reply a icmp frag needed with a size that sctp won't accept but
will retransmit anyway.
Marcelo
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: INFO: task hung in bpf_exit_net
2017-12-22 19:04 ` Marcelo Ricardo Leitner
@ 2018-02-02 23:39 ` Eric Biggers
-1 siblings, 0 replies; 15+ messages in thread
From: Eric Biggers @ 2018-02-02 23:39 UTC (permalink / raw)
To: Marcelo Ricardo Leitner
Cc: Dmitry Vyukov, David Ahern, syzbot, LKML, Ingo Molnar,
Peter Zijlstra, syzkaller-bugs, David Miller, Florian Westphal,
Daniel Borkmann, Xin Long, jakub.kicinski, mschiffer,
Vladislav Yasevich, Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 05:04:37PM -0200, Marcelo Ricardo Leitner wrote:
> On Fri, Dec 22, 2017 at 04:28:07PM -0200, Marcelo Ricardo Leitner wrote:
> > On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
> > ...
> > > > Same with this one, perhaps related to / fixed by:
> > > > http://patchwork.ozlabs.org/patch/850957/
> > > >
> > >
> > >
> > >
> > > Looking at the log, this one seems to be an infinite loop in SCTP code
> > > with console output in it. Kernel is busy printing gazilion of:
> > >
> > > [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > ** 110 printk messages dropped **
> > > [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > ** 103 printk messages dropped **
> > > ...
> > > [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > >
> > > Looks like a different issue.
> > >
> >
> > Oh. I guess this is caused by the interface having a MTU smaller than
> > SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
> > (sctp_icmp_frag_needed) will trigger an instant retransmission.
> > But as the MTU is smaller, SCTP won't update it, but will issue the
> > retransmission anyway.
> >
> > I will test this soon. Should be fairly easy to trigger it.
>
> Reproduced it.
>
> netns A veth0(1500) - veth1(1500) B veth2(508) - veth3(508) C
>
> When A sends a sctp packet bigger than 508, it triggers the issue as B
> will reply a icmp frag needed with a size that sctp won't accept but
> will retransmit anyway.
>
syzbot hasn't encountered this hang again (although, it just happened once in
the first place). I assume it was fixed by commit b6c5734db070, so telling
syzbot this:
#syz fix: sctp: fix the handling of ICMP Frag Needed for too small MTUs
- Eric
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: INFO: task hung in bpf_exit_net
@ 2018-02-02 23:39 ` Eric Biggers
0 siblings, 0 replies; 15+ messages in thread
From: Eric Biggers @ 2018-02-02 23:39 UTC (permalink / raw)
To: Marcelo Ricardo Leitner
Cc: Dmitry Vyukov, David Ahern, syzbot, LKML, Ingo Molnar,
Peter Zijlstra, syzkaller-bugs, David Miller, Florian Westphal,
Daniel Borkmann, Xin Long, jakub.kicinski, mschiffer,
Vladislav Yasevich, Jiri Benc, netdev, Neil Horman, linux-sctp
On Fri, Dec 22, 2017 at 05:04:37PM -0200, Marcelo Ricardo Leitner wrote:
> On Fri, Dec 22, 2017 at 04:28:07PM -0200, Marcelo Ricardo Leitner wrote:
> > On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
> > ...
> > > > Same with this one, perhaps related to / fixed by:
> > > > http://patchwork.ozlabs.org/patch/850957/
> > > >
> > >
> > >
> > >
> > > Looking at the log, this one seems to be an infinite loop in SCTP code
> > > with console output in it. Kernel is busy printing gazilion of:
> > >
> > > [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > ** 110 printk messages dropped **
> > > [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > ** 103 printk messages dropped **
> > > ...
> > > [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > > [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> > > low, using default minimum of 512
> > >
> > > Looks like a different issue.
> > >
> >
> > Oh. I guess this is caused by the interface having a MTU smaller than
> > SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
> > (sctp_icmp_frag_needed) will trigger an instant retransmission.
> > But as the MTU is smaller, SCTP won't update it, but will issue the
> > retransmission anyway.
> >
> > I will test this soon. Should be fairly easy to trigger it.
>
> Reproduced it.
>
> netns A veth0(1500) - veth1(1500) B veth2(508) - veth3(508) C
>
> When A sends a sctp packet bigger than 508, it triggers the issue as B
> will reply a icmp frag needed with a size that sctp won't accept but
> will retransmit anyway.
>
syzbot hasn't encountered this hang again (although, it just happened once in
the first place). I assume it was fixed by commit b6c5734db070, so telling
syzbot this:
#syz fix: sctp: fix the handling of ICMP Frag Needed for too small MTUs
- Eric
^ permalink raw reply [flat|nested] 15+ messages in thread