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* possible deadlock in send_sigurg (2)
@ 2020-10-23  9:07 syzbot
  2020-11-04  9:58 ` syzbot
  2020-11-04 12:18 ` syzbot
  0 siblings, 2 replies; 5+ messages in thread
From: syzbot @ 2020-10-23  9:07 UTC (permalink / raw)
  To: bfields, jlayton, linux-fsdevel, linux-kernel, syzkaller-bugs, viro

Hello,

syzbot found the following issue on:

HEAD commit:    7cf726a5 Merge tag 'linux-kselftest-kunit-5.10-rc1' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14ba8ea0500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=80f536b098d66fd2
dashboard link: https://syzkaller.appspot.com/bug?extid=c5e32344981ad9f33750
compiler:       gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com

========================================================
WARNING: possible irq lock inversion dependency detected
5.9.0-syzkaller #0 Not tainted
--------------------------------------------------------
syz-executor.4/8709 just changed the state of lock:
ffff8880132a3438 (&f->f_owner.lock){.+..}-{2:2}, at: send_sigurg+0x1e/0xac0 fs/fcntl.c:824
but this lock was taken by another, HARDIRQ-safe lock in the past:
 (&dev->event_lock){-...}-{2:2}


and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
Chain exists of:
  &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&f->f_owner.lock);
                               local_irq_disable();
                               lock(&dev->event_lock);
                               lock(&new->fa_lock);
  <Interrupt>
    lock(&dev->event_lock);

 *** DEADLOCK ***

1 lock held by syz-executor.4/8709:
 #0: ffff88802a83c160 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1581 [inline]
 #0: ffff88802a83c160 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_wait_for_connect net/ipv4/af_inet.c:596 [inline]
 #0: ffff88802a83c160 (sk_lock-AF_INET){+.+.}-{0:0}, at: __inet_stream_connect+0x596/0xe30 net/ipv4/af_inet.c:686

the shortest dependencies between 2nd lock and 1st lock:
   -> (&dev->event_lock){-...}-{2:2} {
      IN-HARDIRQ-W at:
                          lock_acquire kernel/locking/lockdep.c:5442 [inline]
                          lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                          __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                          _raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159
                          input_event drivers/input/input.c:440 [inline]
                          input_event+0x7b/0xb0 drivers/input/input.c:433
                          input_report_key include/linux/input.h:417 [inline]
                          psmouse_report_standard_buttons+0x2c/0x80 drivers/input/mouse/psmouse-base.c:123
                          psmouse_report_standard_packet drivers/input/mouse/psmouse-base.c:141 [inline]
                          psmouse_process_byte+0x1e1/0x890 drivers/input/mouse/psmouse-base.c:232
                          psmouse_handle_byte+0x41/0x1b0 drivers/input/mouse/psmouse-base.c:274
                          psmouse_interrupt+0x304/0xf00 drivers/input/mouse/psmouse-base.c:426
                          serio_interrupt+0x88/0x150 drivers/input/serio/serio.c:1002
                          i8042_interrupt+0x27a/0x520 drivers/input/serio/i8042.c:598
                          __handle_irq_event_percpu+0x20b/0x9e0 kernel/irq/handle.c:156
                          handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
                          handle_irq_event+0x102/0x290 kernel/irq/handle.c:213
                          handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:819
                          asm_call_irq_on_stack+0xf/0x20
                          __run_irq_on_irqstack arch/x86/include/asm/irq_stack.h:48 [inline]
                          run_irq_on_irqstack_cond arch/x86/include/asm/irq_stack.h:101 [inline]
                          handle_irq arch/x86/kernel/irq.c:230 [inline]
                          __common_interrupt arch/x86/kernel/irq.c:249 [inline]
                          common_interrupt+0x120/0x200 arch/x86/kernel/irq.c:239
                          asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:622
                          arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline]
                          __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
                          _raw_spin_unlock_irqrestore+0x4d/0x90 kernel/locking/spinlock.c:191
                          spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
                          i8042_command+0x111/0x130 drivers/input/serio/i8042.c:348
                          i8042_aux_write+0xd7/0x120 drivers/input/serio/i8042.c:383
                          serio_write include/linux/serio.h:125 [inline]
                          ps2_do_sendbyte+0x2cc/0x640 drivers/input/serio/libps2.c:40
                          ps2_sendbyte+0x4b/0x90 drivers/input/serio/libps2.c:92
                          cypress_ps2_sendbyte drivers/input/mouse/cypress_ps2.c:42 [inline]
                          cypress_ps2_read_cmd_status drivers/input/mouse/cypress_ps2.c:116 [inline]
                          cypress_send_ext_cmd+0x1cb/0x8a0 drivers/input/mouse/cypress_ps2.c:189
                          cypress_detect+0x75/0x190 drivers/input/mouse/cypress_ps2.c:205
                          psmouse_do_detect drivers/input/mouse/psmouse-base.c:1009 [inline]
                          psmouse_try_protocol+0x211/0x370 drivers/input/mouse/psmouse-base.c:1023
                          psmouse_extensions+0x557/0x930 drivers/input/mouse/psmouse-base.c:1146
                          psmouse_switch_protocol+0x52a/0x740 drivers/input/mouse/psmouse-base.c:1542
                          psmouse_connect+0x5e6/0xfc0 drivers/input/mouse/psmouse-base.c:1632
                          serio_connect_driver drivers/input/serio/serio.c:47 [inline]
                          serio_driver_probe+0x72/0xa0 drivers/input/serio/serio.c:778
                          really_probe+0x282/0x9f0 drivers/base/dd.c:554
                          driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:738
                          device_driver_attach+0x228/0x290 drivers/base/dd.c:1013
                          __driver_attach drivers/base/dd.c:1090 [inline]
                          __driver_attach+0xda/0x240 drivers/base/dd.c:1044
                          bus_for_each_dev+0x147/0x1d0 drivers/base/bus.c:305
                          serio_attach_driver drivers/input/serio/serio.c:808 [inline]
                          serio_handle_event+0x5f6/0xa30 drivers/input/serio/serio.c:227
                          process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
                          worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
                          kthread+0x3b5/0x4a0 kernel/kthread.c:292
                          ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
      INITIAL USE at:
                         lock_acquire kernel/locking/lockdep.c:5442 [inline]
                         lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                         __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                         _raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159
                         input_inject_event+0xa6/0x310 drivers/input/input.c:466
                         __led_set_brightness drivers/leds/led-core.c:48 [inline]
                         led_set_brightness_nopm drivers/leds/led-core.c:275 [inline]
                         led_set_brightness_nosleep+0xe6/0x1a0 drivers/leds/led-core.c:292
                         led_set_brightness+0x134/0x170 drivers/leds/led-core.c:267
                         led_trigger_event drivers/leds/led-triggers.c:387 [inline]
                         led_trigger_event+0x70/0xd0 drivers/leds/led-triggers.c:377
                         kbd_led_trigger_activate+0xfa/0x130 drivers/tty/vt/keyboard.c:1005
                         led_trigger_set+0x61e/0xbd0 drivers/leds/led-triggers.c:195
                         led_trigger_set_default drivers/leds/led-triggers.c:259 [inline]
                         led_trigger_set_default+0x1a6/0x230 drivers/leds/led-triggers.c:246
                         led_classdev_register_ext+0x552/0x6e0 drivers/leds/led-class.c:417
                         led_classdev_register include/linux/leds.h:190 [inline]
                         input_leds_connect+0x3fb/0x740 drivers/input/input-leds.c:139
                         input_attach_handler+0x180/0x1f0 drivers/input/input.c:1031
                         input_register_device.cold+0xf0/0x243 drivers/input/input.c:2229
                         atkbd_connect+0x736/0x9d0 drivers/input/keyboard/atkbd.c:1293
                         serio_connect_driver drivers/input/serio/serio.c:47 [inline]
                         serio_driver_probe+0x72/0xa0 drivers/input/serio/serio.c:778
                         really_probe+0x282/0x9f0 drivers/base/dd.c:554
                         driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:738
                         device_driver_attach+0x228/0x290 drivers/base/dd.c:1013
                         __driver_attach drivers/base/dd.c:1090 [inline]
                         __driver_attach+0xda/0x240 drivers/base/dd.c:1044
                         bus_for_each_dev+0x147/0x1d0 drivers/base/bus.c:305
                         serio_attach_driver drivers/input/serio/serio.c:808 [inline]
                         serio_handle_event+0x5f6/0xa30 drivers/input/serio/serio.c:227
                         process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
                         worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
                         kthread+0x3b5/0x4a0 kernel/kthread.c:292
                         ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
    }
    ... key      at: [<ffffffff8e616a40>] __key.5+0x0/0x40
    ... acquired at:
   __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
   _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
   spin_lock include/linux/spinlock.h:354 [inline]
   evdev_pass_values+0x195/0xa70 drivers/input/evdev.c:262
   evdev_events+0x20c/0x330 drivers/input/evdev.c:307
   input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
   input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
   input_pass_values drivers/input/input.c:134 [inline]
   input_handle_event+0x324/0x1400 drivers/input/input.c:399
   input_inject_event+0x2f5/0x310 drivers/input/input.c:471
   evdev_write+0x424/0x750 drivers/input/evdev.c:530
   vfs_write+0x2b0/0x730 fs/read_write.c:584
   ksys_write+0x1ee/0x250 fs/read_write.c:639
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> (&client->buffer_lock){....}-{2:2} {
     INITIAL USE at:
                       lock_acquire kernel/locking/lockdep.c:5442 [inline]
                       lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
                       _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
                       spin_lock include/linux/spinlock.h:354 [inline]
                       evdev_pass_values+0x195/0xa70 drivers/input/evdev.c:262
                       evdev_events+0x20c/0x330 drivers/input/evdev.c:307
                       input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
                       input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
                       input_pass_values drivers/input/input.c:134 [inline]
                       input_handle_event+0x324/0x1400 drivers/input/input.c:399
                       input_inject_event+0x2f5/0x310 drivers/input/input.c:471
                       evdev_write+0x424/0x750 drivers/input/evdev.c:530
                       vfs_write+0x2b0/0x730 fs/read_write.c:584
                       ksys_write+0x1ee/0x250 fs/read_write.c:639
                       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                       entry_SYSCALL_64_after_hwframe+0x44/0xa9
   }
   ... key      at: [<ffffffff8e616f40>] __key.4+0x0/0x40
   ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
   kill_fasync_rcu fs/fcntl.c:1002 [inline]
   kill_fasync fs/fcntl.c:1023 [inline]
   kill_fasync+0x14b/0x460 fs/fcntl.c:1016
   __pass_event drivers/input/evdev.c:240 [inline]
   evdev_pass_values+0x72a/0xa70 drivers/input/evdev.c:279
   evdev_events+0x20c/0x330 drivers/input/evdev.c:307
   input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
   input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
   input_pass_values drivers/input/input.c:134 [inline]
   input_handle_event+0x324/0x1400 drivers/input/input.c:399
   input_inject_event+0x2f5/0x310 drivers/input/input.c:471
   evdev_write+0x424/0x750 drivers/input/evdev.c:530
   vfs_write+0x2b0/0x730 fs/read_write.c:584
   ksys_write+0x1ee/0x250 fs/read_write.c:639
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> (&new->fa_lock){....}-{2:2} {
    INITIAL USE at:
                     lock_acquire kernel/locking/lockdep.c:5442 [inline]
                     lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                     __raw_write_lock_irq include/linux/rwlock_api_smp.h:196 [inline]
                     _raw_write_lock_irq+0x94/0xd0 kernel/locking/spinlock.c:311
                     fasync_remove_entry+0xb6/0x1f0 fs/fcntl.c:880
                     fasync_helper+0x9e/0xb0 fs/fcntl.c:983
                     __fput+0x70f/0x920 fs/file_table.c:278
                     task_work_run+0xdd/0x190 kernel/task_work.c:141
                     tracehook_notify_resume include/linux/tracehook.h:188 [inline]
                     exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
                     exit_to_user_mode_prepare+0x20e/0x230 kernel/entry/common.c:192
                     syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267
                     entry_SYSCALL_64_after_hwframe+0x44/0xa9
    INITIAL READ USE at:
                          lock_acquire kernel/locking/lockdep.c:5442 [inline]
                          lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                          __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                          _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
                          kill_fasync_rcu fs/fcntl.c:1002 [inline]
                          kill_fasync fs/fcntl.c:1023 [inline]
                          kill_fasync+0x14b/0x460 fs/fcntl.c:1016
                          __pass_event drivers/input/evdev.c:240 [inline]
                          evdev_pass_values+0x72a/0xa70 drivers/input/evdev.c:279
                          evdev_events+0x20c/0x330 drivers/input/evdev.c:307
                          input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
                          input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
                          input_pass_values drivers/input/input.c:134 [inline]
                          input_handle_event+0x324/0x1400 drivers/input/input.c:399
                          input_inject_event+0x2f5/0x310 drivers/input/input.c:471
                          evdev_write+0x424/0x750 drivers/input/evdev.c:530
                          vfs_write+0x2b0/0x730 fs/read_write.c:584
                          ksys_write+0x1ee/0x250 fs/read_write.c:639
                          do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                          entry_SYSCALL_64_after_hwframe+0x44/0xa9
  }
  ... key      at: [<ffffffff8dadc160>] __key.0+0x0/0x40
  ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
   send_sigio+0x24/0x360 fs/fcntl.c:786
   kill_fasync_rcu fs/fcntl.c:1009 [inline]
   kill_fasync fs/fcntl.c:1023 [inline]
   kill_fasync+0x205/0x460 fs/fcntl.c:1016
   __pass_event drivers/input/evdev.c:240 [inline]
   evdev_pass_values+0x72a/0xa70 drivers/input/evdev.c:279
   evdev_events+0x20c/0x330 drivers/input/evdev.c:307
   input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
   input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
   input_pass_values drivers/input/input.c:134 [inline]
   input_handle_event+0x324/0x1400 drivers/input/input.c:399
   input_inject_event+0x2f5/0x310 drivers/input/input.c:471
   evdev_write+0x424/0x750 drivers/input/evdev.c:530
   vfs_write+0x2b0/0x730 fs/read_write.c:584
   ksys_write+0x1ee/0x250 fs/read_write.c:639
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> (&f->f_owner.lock){.+..}-{2:2} {
   HARDIRQ-ON-R at:
                    lock_acquire kernel/locking/lockdep.c:5442 [inline]
                    lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                    __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                    _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
                    send_sigurg+0x1e/0xac0 fs/fcntl.c:824
                    sk_send_sigurg+0x76/0x300 net/core/sock.c:2925
                    tcp_check_urg.isra.0+0x1f4/0x710 net/ipv4/tcp_input.c:5489
                    tcp_urg net/ipv4/tcp_input.c:5530 [inline]
                    tcp_rcv_established+0x106c/0x1e40 net/ipv4/tcp_input.c:5862
                    tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1652
                    sk_backlog_rcv include/net/sock.h:1010 [inline]
                    __release_sock+0x134/0x3a0 net/core/sock.c:2523
                    release_sock+0x54/0x1b0 net/core/sock.c:3053
                    sk_stream_wait_memory+0x5bd/0xe60 net/core/stream.c:145
                    tcp_sendmsg_locked+0x1034/0x2d30 net/ipv4/tcp.c:1402
                    tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1442
                    inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
                    sock_sendmsg_nosec net/socket.c:651 [inline]
                    sock_sendmsg+0xcf/0x120 net/socket.c:671
                    __sys_sendto+0x21c/0x320 net/socket.c:1992
                    __do_sys_sendto net/socket.c:2004 [inline]
                    __se_sys_sendto net/socket.c:2000 [inline]
                    __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
                    do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                    entry_SYSCALL_64_after_hwframe+0x44/0xa9
   INITIAL USE at:
                   lock_acquire kernel/locking/lockdep.c:5442 [inline]
                   lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:196 [inline]
                   _raw_write_lock_irq+0x94/0xd0 kernel/locking/spinlock.c:311
                   f_modown+0x2a/0x390 fs/fcntl.c:90
                   __f_setown fs/fcntl.c:109 [inline]
                   f_setown+0xf4/0x230 fs/fcntl.c:137
                   sock_ioctl+0x263/0x730 net/socket.c:1128
                   vfs_ioctl fs/ioctl.c:48 [inline]
                   __do_sys_ioctl fs/ioctl.c:753 [inline]
                   __se_sys_ioctl fs/ioctl.c:739 [inline]
                   __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
                   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                   entry_SYSCALL_64_after_hwframe+0x44/0xa9
   INITIAL READ USE at:
                        lock_acquire kernel/locking/lockdep.c:5442 [inline]
                        lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
                        __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                        _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
                        send_sigio+0x24/0x360 fs/fcntl.c:786
                        kill_fasync_rcu fs/fcntl.c:1009 [inline]
                        kill_fasync fs/fcntl.c:1023 [inline]
                        kill_fasync+0x205/0x460 fs/fcntl.c:1016
                        __pass_event drivers/input/evdev.c:240 [inline]
                        evdev_pass_values+0x72a/0xa70 drivers/input/evdev.c:279
                        evdev_events+0x20c/0x330 drivers/input/evdev.c:307
                        input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
                        input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
                        input_pass_values drivers/input/input.c:134 [inline]
                        input_handle_event+0x324/0x1400 drivers/input/input.c:399
                        input_inject_event+0x2f5/0x310 drivers/input/input.c:471
                        evdev_write+0x424/0x750 drivers/input/evdev.c:530
                        vfs_write+0x2b0/0x730 fs/read_write.c:584
                        ksys_write+0x1ee/0x250 fs/read_write.c:639
                        do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                        entry_SYSCALL_64_after_hwframe+0x44/0xa9
 }
 ... key      at: [<ffffffff8dadb380>] __key.5+0x0/0x40
 ... acquired at:
   mark_usage kernel/locking/lockdep.c:4311 [inline]
   __lock_acquire+0x11f5/0x5590 kernel/locking/lockdep.c:4791
   lock_acquire kernel/locking/lockdep.c:5442 [inline]
   lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
   send_sigurg+0x1e/0xac0 fs/fcntl.c:824
   sk_send_sigurg+0x76/0x300 net/core/sock.c:2925
   tcp_check_urg.isra.0+0x1f4/0x710 net/ipv4/tcp_input.c:5489
   tcp_urg net/ipv4/tcp_input.c:5530 [inline]
   tcp_rcv_established+0x106c/0x1e40 net/ipv4/tcp_input.c:5862
   tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1652
   sk_backlog_rcv include/net/sock.h:1010 [inline]
   __release_sock+0x134/0x3a0 net/core/sock.c:2523
   release_sock+0x54/0x1b0 net/core/sock.c:3053
   sk_stream_wait_memory+0x5bd/0xe60 net/core/stream.c:145
   tcp_sendmsg_locked+0x1034/0x2d30 net/ipv4/tcp.c:1402
   tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1442
   inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
   sock_sendmsg_nosec net/socket.c:651 [inline]
   sock_sendmsg+0xcf/0x120 net/socket.c:671
   __sys_sendto+0x21c/0x320 net/socket.c:1992
   __do_sys_sendto net/socket.c:2004 [inline]
   __se_sys_sendto net/socket.c:2000 [inline]
   __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9


stack backtrace:
CPU: 0 PID: 8709 Comm: syz-executor.4 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fb lib/dump_stack.c:118
 print_irq_inversion_bug kernel/locking/lockdep.c:4410 [inline]
 check_usage_backwards kernel/locking/lockdep.c:3883 [inline]
 mark_lock_irq kernel/locking/lockdep.c:3973 [inline]
 mark_lock.cold+0x6f/0x74 kernel/locking/lockdep.c:4408
 mark_usage kernel/locking/lockdep.c:4311 [inline]
 __lock_acquire+0x11f5/0x5590 kernel/locking/lockdep.c:4791
 lock_acquire kernel/locking/lockdep.c:5442 [inline]
 lock_acquire+0x219/0x9d0 kernel/locking/lockdep.c:5407
 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
 _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
 send_sigurg+0x1e/0xac0 fs/fcntl.c:824
 sk_send_sigurg+0x76/0x300 net/core/sock.c:2925
 tcp_check_urg.isra.0+0x1f4/0x710 net/ipv4/tcp_input.c:5489
 tcp_urg net/ipv4/tcp_input.c:5530 [inline]
 tcp_rcv_established+0x106c/0x1e40 net/ipv4/tcp_input.c:5862
 tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1652
 sk_backlog_rcv include/net/sock.h:1010 [inline]
 __release_sock+0x134/0x3a0 net/core/sock.c:2523
 release_sock+0x54/0x1b0 net/core/sock.c:3053
 sk_stream_wait_memory+0x5bd/0xe60 net/core/stream.c:145
 tcp_sendmsg_locked+0x1034/0x2d30 net/ipv4/tcp.c:1402
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1442
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 __sys_sendto+0x21c/0x320 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto net/socket.c:2000 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de59
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fcfd761cc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000002e880 RCX: 000000000045de59
RDX: ffffffffffffff58 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 000000000118bf78 R08: 0000000020000100 R09: 0000000000000010
R10: 0000000020008005 R11: 0000000000000246 R12: 000000000118bf2c
R13: 000000000169fb7f R14: 00007fcfd761d9c0 R15: 000000000118bf2c


---
This report 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 issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: possible deadlock in send_sigurg (2)
  2020-10-23  9:07 possible deadlock in send_sigurg (2) syzbot
@ 2020-11-04  9:58 ` syzbot
  2020-11-04 12:18 ` syzbot
  1 sibling, 0 replies; 5+ messages in thread
From: syzbot @ 2020-11-04  9:58 UTC (permalink / raw)
  To: bfields, jlayton, linux-fsdevel, linux-kernel, syzkaller-bugs, viro

syzbot has found a reproducer for the following issue on:

HEAD commit:    4ef8451b Merge tag 'perf-tools-for-v5.10-2020-11-03' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16ab063a500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61033507391c77ff
dashboard link: https://syzkaller.appspot.com/bug?extid=c5e32344981ad9f33750
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15197862500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13c59f6c500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com

netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based  firewall rule not found. Use the iptables CT target to attach helpers instead.
========================================================
WARNING: possible irq lock inversion dependency detected
5.10.0-rc2-syzkaller #0 Not tainted
--------------------------------------------------------
syz-executor981/8491 just changed the state of lock:
ffff88801798e638 (&f->f_owner.lock){.+..}-{2:2}, at: send_sigurg+0x1e/0xac0 fs/fcntl.c:824
but this lock was taken by another, HARDIRQ-safe lock in the past:
 (&dev->event_lock){-...}-{2:2}


and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
Chain exists of:
  &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&f->f_owner.lock);
                               local_irq_disable();
                               lock(&dev->event_lock);
                               lock(&new->fa_lock);
  <Interrupt>
    lock(&dev->event_lock);

 *** DEADLOCK ***

1 lock held by syz-executor981/8491:
 #0: ffff888023e118a0 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1581 [inline]
 #0: ffff888023e118a0 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_wait_for_connect net/ipv4/af_inet.c:596 [inline]
 #0: ffff888023e118a0 (sk_lock-AF_INET){+.+.}-{0:0}, at: __inet_stream_connect+0x596/0xe30 net/ipv4/af_inet.c:686

the shortest dependencies between 2nd lock and 1st lock:
   -> (&dev->event_lock){-...}-{2:2} {
      IN-HARDIRQ-W at:
                          lock_acquire kernel/locking/lockdep.c:5436 [inline]
                          lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
                          __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                          _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159
                          input_event drivers/input/input.c:440 [inline]
                          input_event+0x7b/0xb0 drivers/input/input.c:433
                          input_report_key include/linux/input.h:417 [inline]
                          psmouse_report_standard_buttons+0x2c/0x80 drivers/input/mouse/psmouse-base.c:123
                          psmouse_report_standard_packet drivers/input/mouse/psmouse-base.c:141 [inline]
                          psmouse_process_byte+0x1e1/0x890 drivers/input/mouse/psmouse-base.c:232
                          psmouse_handle_byte+0x41/0x1b0 drivers/input/mouse/psmouse-base.c:274
                          psmouse_interrupt+0x304/0xf00 drivers/input/mouse/psmouse-base.c:426
                          serio_interrupt+0x88/0x150 drivers/input/serio/serio.c:1002
                          i8042_interrupt+0x27a/0x520 drivers/input/serio/i8042.c:598
                          __handle_irq_event_percpu+0x303/0x8f0 kernel/irq/handle.c:156
                          handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
                          handle_irq_event+0x102/0x290 kernel/irq/handle.c:213
                          handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:819
                          asm_call_irq_on_stack+0xf/0x20
                          __run_irq_on_irqstack arch/x86/include/asm/irq_stack.h:48 [inline]
                          run_irq_on_irqstack_cond arch/x86/include/asm/irq_stack.h:101 [inline]
                          handle_irq arch/x86/kernel/irq.c:230 [inline]
                          __common_interrupt arch/x86/kernel/irq.c:249 [inline]
                          common_interrupt+0x120/0x200 arch/x86/kernel/irq.c:239
                          asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:622
                          native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
                          arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
                          acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
                          acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:517
                          acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:648
                          cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237
                          cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:351
                          call_cpuidle kernel/sched/idle.c:132 [inline]
                          cpuidle_idle_call kernel/sched/idle.c:213 [inline]
                          do_idle+0x3e1/0x590 kernel/sched/idle.c:273
                          cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:369
                          start_secondary+0x266/0x340 arch/x86/kernel/smpboot.c:266
                          secondary_startup_64_no_verify+0xb0/0xbb
      INITIAL USE at:
                         lock_acquire kernel/locking/lockdep.c:5436 [inline]
                         lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
                         __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                         _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159
                         input_inject_event+0xa6/0x310 drivers/input/input.c:466
                         __led_set_brightness drivers/leds/led-core.c:48 [inline]
                         led_set_brightness_nopm drivers/leds/led-core.c:275 [inline]
                         led_set_brightness_nosleep+0xe6/0x1a0 drivers/leds/led-core.c:292
                         led_set_brightness+0x134/0x170 drivers/leds/led-core.c:267
                         led_trigger_event drivers/leds/led-triggers.c:387 [inline]
                         led_trigger_event+0x70/0xd0 drivers/leds/led-triggers.c:377
                         kbd_led_trigger_activate+0xfa/0x130 drivers/tty/vt/keyboard.c:1010
                         led_trigger_set+0x61e/0xbd0 drivers/leds/led-triggers.c:195
                         led_trigger_set_default drivers/leds/led-triggers.c:259 [inline]
                         led_trigger_set_default+0x1a6/0x230 drivers/leds/led-triggers.c:246
                         led_classdev_register_ext+0x5b1/0x7c0 drivers/leds/led-class.c:417
                         led_classdev_register include/linux/leds.h:190 [inline]
                         input_leds_connect+0x3fb/0x740 drivers/input/input-leds.c:139
                         input_attach_handler+0x180/0x1f0 drivers/input/input.c:1031
                         input_register_device.cold+0xf0/0x307 drivers/input/input.c:2229
                         atkbd_connect+0x736/0xa00 drivers/input/keyboard/atkbd.c:1293
                         serio_connect_driver drivers/input/serio/serio.c:47 [inline]
                         serio_driver_probe+0x72/0xa0 drivers/input/serio/serio.c:778
                         really_probe+0x291/0xde0 drivers/base/dd.c:554
                         driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738
                         device_driver_attach+0x228/0x290 drivers/base/dd.c:1013
                         __driver_attach+0x15b/0x2f0 drivers/base/dd.c:1090
                         bus_for_each_dev+0x147/0x1d0 drivers/base/bus.c:305
                         serio_attach_driver drivers/input/serio/serio.c:808 [inline]
                         serio_handle_event+0x5f6/0xa30 drivers/input/serio/serio.c:227
                         process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
                         worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
                         kthread+0x3af/0x4a0 kernel/kthread.c:292
                         ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
    }
    ... key      at: [<ffffffff8fa24220>] __key.8+0x0/0x40
    ... acquired at:
   __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
   _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
   spin_lock include/linux/spinlock.h:354 [inline]
   evdev_pass_values.part.0+0xf6/0x970 drivers/input/evdev.c:261
   evdev_pass_values drivers/input/evdev.c:253 [inline]
   evdev_events+0x28b/0x3f0 drivers/input/evdev.c:306
   input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
   input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
   input_pass_values drivers/input/input.c:134 [inline]
   input_handle_event+0x324/0x1400 drivers/input/input.c:399
   input_inject_event+0x2f5/0x310 drivers/input/input.c:471
   evdev_write+0x430/0x760 drivers/input/evdev.c:530
   vfs_write+0x28e/0x700 fs/read_write.c:603
   ksys_write+0x1ee/0x250 fs/read_write.c:658
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> (&client->buffer_lock){....}-{2:2} {
     INITIAL USE at:
                       lock_acquire kernel/locking/lockdep.c:5436 [inline]
                       lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
                       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
                       _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
                       spin_lock include/linux/spinlock.h:354 [inline]
                       evdev_pass_values.part.0+0xf6/0x970 drivers/input/evdev.c:261
                       evdev_pass_values drivers/input/evdev.c:253 [inline]
                       evdev_events+0x28b/0x3f0 drivers/input/evdev.c:306
                       input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
                       input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
                       input_pass_values drivers/input/input.c:134 [inline]
                       input_handle_event+0x324/0x1400 drivers/input/input.c:399
                       input_inject_event+0x2f5/0x310 drivers/input/input.c:471
                       evdev_write+0x430/0x760 drivers/input/evdev.c:530
                       vfs_write+0x28e/0x700 fs/read_write.c:603
                       ksys_write+0x1ee/0x250 fs/read_write.c:658
                       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                       entry_SYSCALL_64_after_hwframe+0x44/0xa9
   }
   ... key      at: [<ffffffff8fa24720>] __key.4+0x0/0x40
   ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
   kill_fasync_rcu fs/fcntl.c:1002 [inline]
   kill_fasync fs/fcntl.c:1023 [inline]
   kill_fasync+0x14b/0x460 fs/fcntl.c:1016
   __pass_event drivers/input/evdev.c:240 [inline]
   evdev_pass_values.part.0+0x64e/0x970 drivers/input/evdev.c:278
   evdev_pass_values drivers/input/evdev.c:253 [inline]
   evdev_events+0x28b/0x3f0 drivers/input/evdev.c:306
   input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
   input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
   input_pass_values drivers/input/input.c:134 [inline]
   input_handle_event+0x324/0x1400 drivers/input/input.c:399
   input_inject_event+0x2f5/0x310 drivers/input/input.c:471
   evdev_write+0x430/0x760 drivers/input/evdev.c:530
   vfs_write+0x28e/0x700 fs/read_write.c:603
   ksys_write+0x1ee/0x250 fs/read_write.c:658
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> (&new->fa_lock){....}-{2:2} {
    INITIAL READ USE at:
                          lock_acquire kernel/locking/lockdep.c:5436 [inline]
                          lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
                          __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                          _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
                          kill_fasync_rcu fs/fcntl.c:1002 [inline]
                          kill_fasync fs/fcntl.c:1023 [inline]
                          kill_fasync+0x14b/0x460 fs/fcntl.c:1016
                          __pass_event drivers/input/evdev.c:240 [inline]
                          evdev_pass_values.part.0+0x64e/0x970 drivers/input/evdev.c:278
                          evdev_pass_values drivers/input/evdev.c:253 [inline]
                          evdev_events+0x28b/0x3f0 drivers/input/evdev.c:306
                          input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
                          input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
                          input_pass_values drivers/input/input.c:134 [inline]
                          input_handle_event+0x324/0x1400 drivers/input/input.c:399
                          input_inject_event+0x2f5/0x310 drivers/input/input.c:471
                          evdev_write+0x430/0x760 drivers/input/evdev.c:530
                          vfs_write+0x28e/0x700 fs/read_write.c:603
                          ksys_write+0x1ee/0x250 fs/read_write.c:658
                          do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                          entry_SYSCALL_64_after_hwframe+0x44/0xa9
  }
  ... key      at: [<ffffffff8ef5e800>] __key.0+0x0/0x40
  ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
   send_sigio+0x24/0x360 fs/fcntl.c:786
   kill_fasync_rcu fs/fcntl.c:1009 [inline]
   kill_fasync fs/fcntl.c:1023 [inline]
   kill_fasync+0x205/0x460 fs/fcntl.c:1016
   __pass_event drivers/input/evdev.c:240 [inline]
   evdev_pass_values.part.0+0x64e/0x970 drivers/input/evdev.c:278
   evdev_pass_values drivers/input/evdev.c:253 [inline]
   evdev_events+0x28b/0x3f0 drivers/input/evdev.c:306
   input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
   input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
   input_pass_values drivers/input/input.c:134 [inline]
   input_handle_event+0x324/0x1400 drivers/input/input.c:399
   input_inject_event+0x2f5/0x310 drivers/input/input.c:471
   evdev_write+0x430/0x760 drivers/input/evdev.c:530
   vfs_write+0x28e/0x700 fs/read_write.c:603
   ksys_write+0x1ee/0x250 fs/read_write.c:658
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> (&f->f_owner.lock){.+..}-{2:2} {
   HARDIRQ-ON-R at:
                    lock_acquire kernel/locking/lockdep.c:5436 [inline]
                    lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
                    __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                    _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
                    send_sigurg+0x1e/0xac0 fs/fcntl.c:824
                    sk_send_sigurg+0x76/0x300 net/core/sock.c:2925
                    tcp_check_urg.isra.0+0x1f4/0x710 net/ipv4/tcp_input.c:5490
                    tcp_urg net/ipv4/tcp_input.c:5531 [inline]
                    tcp_rcv_established+0x106c/0x1eb0 net/ipv4/tcp_input.c:5865
                    tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1652
                    sk_backlog_rcv include/net/sock.h:1010 [inline]
                    __release_sock+0x134/0x3a0 net/core/sock.c:2523
                    release_sock+0x54/0x1b0 net/core/sock.c:3053
                    sk_stream_wait_memory+0x5bd/0xe60 net/core/stream.c:145
                    tcp_sendmsg_locked+0x1034/0x2d20 net/ipv4/tcp.c:1404
                    tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1444
                    inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
                    sock_sendmsg_nosec net/socket.c:651 [inline]
                    sock_sendmsg+0xcf/0x120 net/socket.c:671
                    __sys_sendto+0x21c/0x320 net/socket.c:1992
                    __do_sys_sendto net/socket.c:2004 [inline]
                    __se_sys_sendto net/socket.c:2000 [inline]
                    __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
                    do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                    entry_SYSCALL_64_after_hwframe+0x44/0xa9
   INITIAL READ USE at:
                        lock_acquire kernel/locking/lockdep.c:5436 [inline]
                        lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
                        __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                        _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
                        send_sigio+0x24/0x360 fs/fcntl.c:786
                        kill_fasync_rcu fs/fcntl.c:1009 [inline]
                        kill_fasync fs/fcntl.c:1023 [inline]
                        kill_fasync+0x205/0x460 fs/fcntl.c:1016
                        __pass_event drivers/input/evdev.c:240 [inline]
                        evdev_pass_values.part.0+0x64e/0x970 drivers/input/evdev.c:278
                        evdev_pass_values drivers/input/evdev.c:253 [inline]
                        evdev_events+0x28b/0x3f0 drivers/input/evdev.c:306
                        input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
                        input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
                        input_pass_values drivers/input/input.c:134 [inline]
                        input_handle_event+0x324/0x1400 drivers/input/input.c:399
                        input_inject_event+0x2f5/0x310 drivers/input/input.c:471
                        evdev_write+0x430/0x760 drivers/input/evdev.c:530
                        vfs_write+0x28e/0x700 fs/read_write.c:603
                        ksys_write+0x1ee/0x250 fs/read_write.c:658
                        do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                        entry_SYSCALL_64_after_hwframe+0x44/0xa9
 }
 ... key      at: [<ffffffff8ef5da20>] __key.5+0x0/0x40
 ... acquired at:
   mark_usage kernel/locking/lockdep.c:4311 [inline]
   __lock_acquire+0x11f5/0x5590 kernel/locking/lockdep.c:4785
   lock_acquire kernel/locking/lockdep.c:5436 [inline]
   lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
   send_sigurg+0x1e/0xac0 fs/fcntl.c:824
   sk_send_sigurg+0x76/0x300 net/core/sock.c:2925
   tcp_check_urg.isra.0+0x1f4/0x710 net/ipv4/tcp_input.c:5490
   tcp_urg net/ipv4/tcp_input.c:5531 [inline]
   tcp_rcv_established+0x106c/0x1eb0 net/ipv4/tcp_input.c:5865
   tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1652
   sk_backlog_rcv include/net/sock.h:1010 [inline]
   __release_sock+0x134/0x3a0 net/core/sock.c:2523
   release_sock+0x54/0x1b0 net/core/sock.c:3053
   sk_stream_wait_memory+0x5bd/0xe60 net/core/stream.c:145
   tcp_sendmsg_locked+0x1034/0x2d20 net/ipv4/tcp.c:1404
   tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1444
   inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
   sock_sendmsg_nosec net/socket.c:651 [inline]
   sock_sendmsg+0xcf/0x120 net/socket.c:671
   __sys_sendto+0x21c/0x320 net/socket.c:1992
   __do_sys_sendto net/socket.c:2004 [inline]
   __se_sys_sendto net/socket.c:2000 [inline]
   __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9


stack backtrace:
CPU: 0 PID: 8491 Comm: syz-executor981 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:118
 print_irq_inversion_bug kernel/locking/lockdep.c:3739 [inline]
 check_usage_backwards kernel/locking/lockdep.c:3883 [inline]
 mark_lock_irq kernel/locking/lockdep.c:3973 [inline]
 mark_lock.cold+0x1a/0x74 kernel/locking/lockdep.c:4410
 mark_usage kernel/locking/lockdep.c:4311 [inline]
 __lock_acquire+0x11f5/0x5590 kernel/locking/lockdep.c:4785
 lock_acquire kernel/locking/lockdep.c:5436 [inline]
 lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
 _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
 send_sigurg+0x1e/0xac0 fs/fcntl.c:824
 sk_send_sigurg+0x76/0x300 net/core/sock.c:2925
 tcp_check_urg.isra.0+0x1f4/0x710 net/ipv4/tcp_input.c:5490
 tcp_urg net/ipv4/tcp_input.c:5531 [inline]
 tcp_rcv_established+0x106c/0x1eb0 net/ipv4/tcp_input.c:5865
 tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1652
 sk_backlog_rcv include/net/sock.h:1010 [inline]
 __release_sock+0x134/0x3a0 net/core/sock.c:2523
 release_sock+0x54/0x1b0 net/core/sock.c:3053
 sk_stream_wait_memory+0x5bd/0xe60 net/core/stream.c:145
 tcp_sendmsg_locked+0x1034/0x2d20 net/ipv4/tcp.c:1404
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1444
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 __sys_sendto+0x21c/0x320 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto net/socket.c:2000 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x447309
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b d2 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffd9b651c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000447309
RDX: ffffffffffffff58 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00007fffd9b651e0 R08: 0000000020000100 R09: 0000000000000010
R10: 0000000020008005 R11: 0000000000000246 R12: 00007fffd9b651f0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: possible deadlock in send_sigurg (2)
  2020-10-23  9:07 possible deadlock in send_sigurg (2) syzbot
  2020-11-04  9:58 ` syzbot
@ 2020-11-04 12:18 ` syzbot
  2020-11-05  6:23   ` Boqun Feng
  1 sibling, 1 reply; 5+ messages in thread
From: syzbot @ 2020-11-04 12:18 UTC (permalink / raw)
  To: bfields, boqun.feng, jlayton, linux-fsdevel, linux-kernel, mingo,
	peterz, syzkaller-bugs, viro, will

syzbot has bisected this issue to:

commit e918188611f073063415f40fae568fa4d86d9044
Author: Boqun Feng <boqun.feng@gmail.com>
Date:   Fri Aug 7 07:42:20 2020 +0000

    locking: More accurate annotations for read_lock()

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14142732500000
start commit:   4ef8451b Merge tag 'perf-tools-for-v5.10-2020-11-03' of gi..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=16142732500000
console output: https://syzkaller.appspot.com/x/log.txt?x=12142732500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61033507391c77ff
dashboard link: https://syzkaller.appspot.com/bug?extid=c5e32344981ad9f33750
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15197862500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13c59f6c500000

Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com
Fixes: e918188611f0 ("locking: More accurate annotations for read_lock()")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: possible deadlock in send_sigurg (2)
  2020-11-04 12:18 ` syzbot
@ 2020-11-05  6:23   ` Boqun Feng
  2020-11-05 12:45     ` Jeff Layton
  0 siblings, 1 reply; 5+ messages in thread
From: Boqun Feng @ 2020-11-05  6:23 UTC (permalink / raw)
  To: syzbot
  Cc: bfields, jlayton, linux-fsdevel, linux-kernel, mingo, peterz,
	syzkaller-bugs, viro, will

Hi,

On Wed, Nov 04, 2020 at 04:18:08AM -0800, syzbot wrote:
> syzbot has bisected this issue to:
> 
> commit e918188611f073063415f40fae568fa4d86d9044
> Author: Boqun Feng <boqun.feng@gmail.com>
> Date:   Fri Aug 7 07:42:20 2020 +0000
> 
>     locking: More accurate annotations for read_lock()
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14142732500000
> start commit:   4ef8451b Merge tag 'perf-tools-for-v5.10-2020-11-03' of gi..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=16142732500000
> console output: https://syzkaller.appspot.com/x/log.txt?x=12142732500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=61033507391c77ff
> dashboard link: https://syzkaller.appspot.com/bug?extid=c5e32344981ad9f33750
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15197862500000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13c59f6c500000
> 
> Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com
> Fixes: e918188611f0 ("locking: More accurate annotations for read_lock()")
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Thanks for reporting this, and this is actually a deadlock potential
detected by the newly added recursive read deadlock detection as my
analysis:

	https://lore.kernel.org/lkml/20200910071523.GF7922@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net

Besides, other reports[1][2] are caused by the same problem. I made a
fix for this, please have a try and see if it's get fixed.

Regards,
Boqun

[1]: https://lore.kernel.org/lkml/000000000000d7136005aee14bf9@google.com
[2]: https://lore.kernel.org/lkml/0000000000006e29ed05b3009b04@google.com

----------------------------------------------------->8
From 7fbe730fcff2d7909be034cf6dc8bf0604d0bf14 Mon Sep 17 00:00:00 2001
From: Boqun Feng <boqun.feng@gmail.com>
Date: Thu, 5 Nov 2020 14:02:57 +0800
Subject: [PATCH] fs/fcntl: Fix potential deadlock in send_sig{io, urg}()

Syzbot reports a potential deadlock found by the newly added recursive
read deadlock detection in lockdep:

[...] ========================================================
[...] WARNING: possible irq lock inversion dependency detected
[...] 5.9.0-rc2-syzkaller #0 Not tainted
[...] --------------------------------------------------------
[...] syz-executor.1/10214 just changed the state of lock:
[...] ffff88811f506338 (&f->f_owner.lock){.+..}-{2:2}, at: send_sigurg+0x1d/0x200
[...] but this lock was taken by another, HARDIRQ-safe lock in the past:
[...]  (&dev->event_lock){-...}-{2:2}
[...]
[...]
[...] and interrupts could create inverse lock ordering between them.
[...]
[...]
[...] other info that might help us debug this:
[...] Chain exists of:
[...]   &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock
[...]
[...]  Possible interrupt unsafe locking scenario:
[...]
[...]        CPU0                    CPU1
[...]        ----                    ----
[...]   lock(&f->f_owner.lock);
[...]                                local_irq_disable();
[...]                                lock(&dev->event_lock);
[...]                                lock(&new->fa_lock);
[...]   <Interrupt>
[...]     lock(&dev->event_lock);
[...]
[...]  *** DEADLOCK ***

The corresponding deadlock case is as followed:

	CPU 0		CPU 1		CPU 2
	read_lock(&fown->lock);
			spin_lock_irqsave(&dev->event_lock, ...)
					write_lock_irq(&filp->f_owner.lock); // wait for the lock
			read_lock(&fown-lock); // have to wait until the writer release
					       // due to the fairness
	<interrupted>
	spin_lock_irqsave(&dev->event_lock); // wait for the lock

The lock dependency on CPU 1 happens if there exists a call sequence:

	input_inject_event():
	  spin_lock_irqsave(&dev->event_lock,...);
	  input_handle_event():
	    input_pass_values():
	      input_to_handler():
	        handler->event(): // evdev_event()
	          evdev_pass_values():
	            spin_lock(&client->buffer_lock);
	            __pass_event():
	              kill_fasync():
	                kill_fasync_rcu():
	                  read_lock(&fa->fa_lock);
	                  send_sigio():
	                    read_lock(&fown->lock);

To fix this, make the reader in send_sigurg() and send_sigio() use
read_lock_irqsave() and read_lock_irqrestore().

Reported-by: syzbot+22e87cdf94021b984aa6@syzkaller.appspotmail.com
Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 fs/fcntl.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 19ac5baad50f..05b36b28f2e8 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -781,9 +781,10 @@ void send_sigio(struct fown_struct *fown, int fd, int band)
 {
 	struct task_struct *p;
 	enum pid_type type;
+	unsigned long flags;
 	struct pid *pid;
 	
-	read_lock(&fown->lock);
+	read_lock_irqsave(&fown->lock, flags);
 
 	type = fown->pid_type;
 	pid = fown->pid;
@@ -804,7 +805,7 @@ void send_sigio(struct fown_struct *fown, int fd, int band)
 		read_unlock(&tasklist_lock);
 	}
  out_unlock_fown:
-	read_unlock(&fown->lock);
+	read_unlock_irqrestore(&fown->lock, flags);
 }
 
 static void send_sigurg_to_task(struct task_struct *p,
@@ -819,9 +820,10 @@ int send_sigurg(struct fown_struct *fown)
 	struct task_struct *p;
 	enum pid_type type;
 	struct pid *pid;
+	unsigned long flags;
 	int ret = 0;
 	
-	read_lock(&fown->lock);
+	read_lock_irqsave(&fown->lock, flags);
 
 	type = fown->pid_type;
 	pid = fown->pid;
@@ -844,7 +846,7 @@ int send_sigurg(struct fown_struct *fown)
 		read_unlock(&tasklist_lock);
 	}
  out_unlock_fown:
-	read_unlock(&fown->lock);
+	read_unlock_irqrestore(&fown->lock, flags);
 	return ret;
 }
 
-- 
2.28.0


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: possible deadlock in send_sigurg (2)
  2020-11-05  6:23   ` Boqun Feng
@ 2020-11-05 12:45     ` Jeff Layton
  0 siblings, 0 replies; 5+ messages in thread
From: Jeff Layton @ 2020-11-05 12:45 UTC (permalink / raw)
  To: Boqun Feng, syzbot
  Cc: bfields, linux-fsdevel, linux-kernel, mingo, peterz,
	syzkaller-bugs, viro, will

On Thu, 2020-11-05 at 14:23 +0800, Boqun Feng wrote:
> Hi,
> 
> On Wed, Nov 04, 2020 at 04:18:08AM -0800, syzbot wrote:
> > syzbot has bisected this issue to:
> > 
> > commit e918188611f073063415f40fae568fa4d86d9044
> > Author: Boqun Feng <boqun.feng@gmail.com>
> > Date:   Fri Aug 7 07:42:20 2020 +0000
> > 
> >     locking: More accurate annotations for read_lock()
> > 
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14142732500000
> > start commit:   4ef8451b Merge tag 'perf-tools-for-v5.10-2020-11-03' of gi..
> > git tree:       upstream
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=16142732500000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=12142732500000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=61033507391c77ff
> > dashboard link: https://syzkaller.appspot.com/bug?extid=c5e32344981ad9f33750
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15197862500000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13c59f6c500000
> > 
> > Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com
> > Fixes: e918188611f0 ("locking: More accurate annotations for read_lock()")
> > 
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> 
> Thanks for reporting this, and this is actually a deadlock potential
> detected by the newly added recursive read deadlock detection as my
> analysis:
> 
> 	https://lore.kernel.org/lkml/20200910071523.GF7922@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net
> 
> Besides, other reports[1][2] are caused by the same problem. I made a
> fix for this, please have a try and see if it's get fixed.
> 
> Regards,
> Boqun
> 
> [1]: https://lore.kernel.org/lkml/000000000000d7136005aee14bf9@google.com
> [2]: https://lore.kernel.org/lkml/0000000000006e29ed05b3009b04@google.com
> 
> ----------------------------------------------------->8
> From 7fbe730fcff2d7909be034cf6dc8bf0604d0bf14 Mon Sep 17 00:00:00 2001
> From: Boqun Feng <boqun.feng@gmail.com>
> Date: Thu, 5 Nov 2020 14:02:57 +0800
> Subject: [PATCH] fs/fcntl: Fix potential deadlock in send_sig{io, urg}()
> 
> Syzbot reports a potential deadlock found by the newly added recursive
> read deadlock detection in lockdep:
> 
> [...] ========================================================
> [...] WARNING: possible irq lock inversion dependency detected
> [...] 5.9.0-rc2-syzkaller #0 Not tainted
> [...] --------------------------------------------------------
> [...] syz-executor.1/10214 just changed the state of lock:
> [...] ffff88811f506338 (&f->f_owner.lock){.+..}-{2:2}, at: send_sigurg+0x1d/0x200
> [...] but this lock was taken by another, HARDIRQ-safe lock in the past:
> [...]  (&dev->event_lock){-...}-{2:2}
> [...]
> [...]
> [...] and interrupts could create inverse lock ordering between them.
> [...]
> [...]
> [...] other info that might help us debug this:
> [...] Chain exists of:
> [...]   &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock
> [...]
> [...]  Possible interrupt unsafe locking scenario:
> [...]
> [...]        CPU0                    CPU1
> [...]        ----                    ----
> [...]   lock(&f->f_owner.lock);
> [...]                                local_irq_disable();
> [...]                                lock(&dev->event_lock);
> [...]                                lock(&new->fa_lock);
> [...]   <Interrupt>
> [...]     lock(&dev->event_lock);
> [...]
> [...]  *** DEADLOCK ***
> 
> The corresponding deadlock case is as followed:
> 
> 	CPU 0		CPU 1		CPU 2
> 	read_lock(&fown->lock);
> 			spin_lock_irqsave(&dev->event_lock, ...)
> 					write_lock_irq(&filp->f_owner.lock); // wait for the lock
> 			read_lock(&fown-lock); // have to wait until the writer release
> 					       // due to the fairness
> 	<interrupted>
> 	spin_lock_irqsave(&dev->event_lock); // wait for the lock
> 
> The lock dependency on CPU 1 happens if there exists a call sequence:
> 
> 	input_inject_event():
> 	  spin_lock_irqsave(&dev->event_lock,...);
> 	  input_handle_event():
> 	    input_pass_values():
> 	      input_to_handler():
> 	        handler->event(): // evdev_event()
> 	          evdev_pass_values():
> 	            spin_lock(&client->buffer_lock);
> 	            __pass_event():
> 	              kill_fasync():
> 	                kill_fasync_rcu():
> 	                  read_lock(&fa->fa_lock);
> 	                  send_sigio():
> 	                    read_lock(&fown->lock);
> 
> To fix this, make the reader in send_sigurg() and send_sigio() use
> read_lock_irqsave() and read_lock_irqrestore().
> 
> Reported-by: syzbot+22e87cdf94021b984aa6@syzkaller.appspotmail.com
> Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> ---
>  fs/fcntl.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/fcntl.c b/fs/fcntl.c
> index 19ac5baad50f..05b36b28f2e8 100644
> --- a/fs/fcntl.c
> +++ b/fs/fcntl.c
> @@ -781,9 +781,10 @@ void send_sigio(struct fown_struct *fown, int fd, int band)
>  {
>  	struct task_struct *p;
>  	enum pid_type type;
> +	unsigned long flags;
>  	struct pid *pid;
>  	
> -	read_lock(&fown->lock);
> +	read_lock_irqsave(&fown->lock, flags);
>  
> 
>  	type = fown->pid_type;
>  	pid = fown->pid;
> @@ -804,7 +805,7 @@ void send_sigio(struct fown_struct *fown, int fd, int band)
>  		read_unlock(&tasklist_lock);
>  	}
>   out_unlock_fown:
> -	read_unlock(&fown->lock);
> +	read_unlock_irqrestore(&fown->lock, flags);
>  }
>  
> 
>  static void send_sigurg_to_task(struct task_struct *p,
> @@ -819,9 +820,10 @@ int send_sigurg(struct fown_struct *fown)
>  	struct task_struct *p;
>  	enum pid_type type;
>  	struct pid *pid;
> +	unsigned long flags;
>  	int ret = 0;
>  	
> -	read_lock(&fown->lock);
> +	read_lock_irqsave(&fown->lock, flags);
>  
> 
>  	type = fown->pid_type;
>  	pid = fown->pid;
> @@ -844,7 +846,7 @@ int send_sigurg(struct fown_struct *fown)
>  		read_unlock(&tasklist_lock);
>  	}
>   out_unlock_fown:
> -	read_unlock(&fown->lock);
> +	read_unlock_irqrestore(&fown->lock, flags);
>  	return ret;
>  }
>  
> 

Thanks Boqun,

This looks sane to me. I'll go ahead and pull it into -next for now, and
it should make v5.11. Let me know if you think it needs to go in sooner.

Thanks!
-- 
Jeff Layton <jlayton@kernel.org>


^ permalink raw reply	[flat|nested] 5+ messages in thread

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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-10-23  9:07 possible deadlock in send_sigurg (2) syzbot
2020-11-04  9:58 ` syzbot
2020-11-04 12:18 ` syzbot
2020-11-05  6:23   ` Boqun Feng
2020-11-05 12:45     ` Jeff Layton

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