syzbot


INFO: task hung in ppp_ioctl (3)

Status: auto-obsoleted due to no activity on 2025/03/16 11:29
Subsystems: ppp
[Documentation on labels]
First crash: 218d, last: 135d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ppp_ioctl ppp 1 1289d 1289d 0/28 auto-closed as invalid on 2022/01/17 01:14
linux-6.1 INFO: task hung in ppp_ioctl 1 394d 394d 0/3 auto-obsoleted due to no activity on 2024/07/10 10:43
upstream INFO: task hung in ppp_ioctl (2) ppp 18 313d 401d 0/28 auto-obsoleted due to no activity on 2024/08/31 09:24
linux-5.15 INFO: task hung in ppp_ioctl 2 314d 322d 0/3 auto-obsoleted due to no activity on 2024/09/28 11:13

Sample crash report:
INFO: task syz.3.1306:10434 blocked for more than 143 seconds.
      Not tainted 6.12.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1306      state:D stack:27360 pid:10434 tgid:10409 ppid:9959   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x18af/0x4bd0 kernel/sched/core.c:6690
 __schedule_loop kernel/sched/core.c:6767 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6782
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6839
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f13d7d7dff9
RSP: 002b:00007f13d8b2c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f13d7f36208 RCX: 00007f13d7d7dff9
RDX: 0000000020002eae RSI: 0000000040047451 RDI: 0000000000000006
RBP: 00007f13d7df0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f13d7f36208 R15: 00007f13d805fa28
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/0:1/9:
 #0: ffff8880212f1d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff8880212f1d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc900000e7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc900000e7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffff888028d74190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline]
 #2: ffff888028d74190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1fe/0x5150 drivers/usb/core/hub.c:5849
 #3: ffff888028d77510 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3206 [inline]
 #3: ffff888028d77510 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5418 [inline]
 #3: ffff888028d77510 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5661 [inline]
 #3: ffff888028d77510 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5821 [inline]
 #3: ffff888028d77510 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x25b9/0x5150 drivers/usb/core/hub.c:5903
 #4: ffff888028829e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5419 [inline]
 #4: ffff888028829e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5661 [inline]
 #4: ffff888028829e68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5821 [inline]
 #4: ffff888028829e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x25f7/0x5150 drivers/usb/core/hub.c:5903
 #5: ffffffff8f5a2010 (ehci_cf_port_reset_rwsem){.+.+}-{3:3}, at: hub_port_reset+0x1f8/0x1b30 drivers/usb/core/hub.c:3021
7 locks held by kworker/u8:1/12:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937e20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
2 locks held by kworker/u8:9/2588:
2 locks held by getty/4990:
 #0: ffff88814bb990a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
2 locks held by syz.3.1306/10428:
1 lock held by syz.3.1306/10434:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.1.1386/10930:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.1.1386/10932:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.0.1401/11125:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.3.1407/11151:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.3.1407/11152:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.4.1432/11302:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.4.1432/11303:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.2.1513/11847:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.2.1513/11848:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.2.1570/12305:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.2.1570/12307:
 #0: ffffffff8f4ba848 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x112/0x1cd0 drivers/net/ppp/ppp_generic.c:729
1 lock held by syz.3.1572/12327:
 #0: ffffffff8e93d3b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #0: ffffffff8e93d3b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
1 lock held by syz.0.1574/12330:
 #0: ffffffff8e93d3b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #0: ffffffff8e93d3b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 12330 Comm: syz.0.1574 Not tainted 6.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:stack_trace_consume_entry+0x0/0x280 kernel/stacktrace.c:83
Code: 0c 7e 00 e9 6a ff ff ff e8 3d c6 45 0a 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 18 48 89 fb 48
RSP: 0018:ffffc90004217538 EFLAGS: 00000282
RAX: ffffffff8bc60520 RBX: ffffc90004217540 RCX: ffffffff917bc000
RDX: ffffffff91969701 RSI: ffffffff8bc60520 RDI: ffffc90004217620
RBP: ffffc900042175d0 R08: ffffc90004217f00 R09: 0000000000000000
R10: ffffc90004217590 R11: ffffffff8180a0c0 R12: ffff888045da3c00
R13: ffffffff8180a0c0 R14: ffffc90004217620 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001403 CR3: 000000000e734000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000004520
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 arch_stack_walk+0x10e/0x150 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x430 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1108 [inline]
 free_unref_page+0xcfb/0xf20 mm/page_alloc.c:2638
 vfree+0x186/0x2e0 mm/vmalloc.c:3361
 kcov_put kernel/kcov.c:439 [inline]
 kcov_close+0x28/0x50 kernel/kcov.c:535
 __fput+0x23f/0x880 fs/file_table.c:431
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa2f/0x28e0 kernel/exit.c:939
 do_group_exit+0x207/0x2c0 kernel/exit.c:1088
 get_signal+0x16a3/0x1740 kernel/signal.c:2917
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffa8d37dff9
Code: Unable to access opcode bytes at 0x7ffa8d37dfcf.
RSP: 002b:00007ffa8e1810e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007ffa8d536060 RCX: 00007ffa8d37dff9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ffa8d536060
RBP: 00007ffa8d536058 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffa8d536064
R13: 0000000000000000 R14: 00007ffa8d65f940 R15: 00007ffa8d65fa28
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/21 22:55 upstream 42f7652d3eb5 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in ppp_ioctl
2024/10/18 04:12 upstream 6efbea77b390 666f77ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in ppp_ioctl
2024/10/15 09:27 upstream eca631b8fe80 14943bb8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in ppp_ioctl
2024/09/26 21:01 upstream 11a299a7933e 0d19f247 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in ppp_ioctl
2024/09/24 09:35 upstream abf2050f51fd 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in ppp_ioctl
2024/10/06 06:34 net 9234a2549cb6 d7906eff .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in ppp_ioctl
2024/12/16 11:28 net-next 92c932b9946c 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in ppp_ioctl
2024/10/23 22:00 net-next 6d858708d465 15fa2979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in ppp_ioctl
2024/10/03 07:44 net-next 6b67e098c9c9 a4c7fd36 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in ppp_ioctl
* Struck through repros no longer work on HEAD.