syzbot


INFO: task hung in ppp_ioctl

Status: auto-closed as invalid on 2022/01/17 01:14
Subsystems: ppp
[Documentation on labels]
First crash: 1089d, last: 1089d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in ppp_ioctl 1 194d 194d 0/3 auto-obsoleted due to no activity on 2024/07/10 10:43
upstream INFO: task hung in ppp_ioctl (2) ppp 18 113d 202d 0/28 auto-obsoleted due to no activity on 2024/08/31 09:24
linux-5.15 INFO: task hung in ppp_ioctl 2 114d 122d 0/3 auto-obsoleted due to no activity on 2024/09/28 11:13

Sample crash report:
INFO: task syz-executor.4:11166 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28256 pid:11166 ppid:  6568 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3323 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1037 [inline]
 ppp_ioctl+0x1876/0x2d50 drivers/net/ppp/ppp_generic.c:710
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7feac7014a39
RSP: 002b:00007feac458a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007feac7117f60 RCX: 00007feac7014a39
RDX: 00000000200000c0 RSI: 00000000c004743e RDI: 0000000000000003
RBP: 00007feac706ec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeff33e3af R14: 00007feac458a300 R15: 0000000000022000
INFO: task syz-executor.4:11174 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28856 pid:11174 ppid:  6568 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7feac7014a39
RSP: 002b:00007feac4569188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007feac7118020 RCX: 00007feac7014a39
RDX: 0000000020000000 RSI: 0000000040047451 RDI: 0000000000000003
RBP: 00007feac706ec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeff33e3af R14: 00007feac4569300 R15: 0000000000022000
INFO: task syz-executor.4:11179 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:29440 pid:11179 ppid:  6568 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7feac7014a39
RSP: 002b:00007feac4548188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007feac71180e0 RCX: 00007feac7014a39
RDX: 0000000020000180 RSI: 0000000040047451 RDI: 0000000000000003
RBP: 00007feac706ec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeff33e3af R14: 00007feac4548300 R15: 0000000000022000
INFO: task syz-executor.4:11237 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28384 pid:11237 ppid:  6568 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7feac7014a39
RSP: 002b:00007feac4527188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007feac71181a0 RCX: 00007feac7014a39
RDX: 00000000200000c0 RSI: 00000000c004743e RDI: 0000000000000003
RBP: 00007feac706ec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeff33e3af R14: 00007feac4527300 R15: 0000000000022000
INFO: task syz-executor.4:11239 blocked for more than 144 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28856 pid:11239 ppid:  6568 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7feac7014a39
RSP: 002b:00007feac4506188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007feac7118260 RCX: 00007feac7014a39
RDX: 0000000020000000 RSI: 0000000040047451 RDI: 0000000000000003
RBP: 00007feac706ec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeff33e3af R14: 00007feac4506300 R15: 0000000000022000
INFO: task syz-executor.3:11231 blocked for more than 144 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:28512 pid:11231 ppid:  6556 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc508c94a39
RSP: 002b:00007fc50620a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc508d97f60 RCX: 00007fc508c94a39
RDX: 00000000200000c0 RSI: 00000000c004743e RDI: 0000000000000003
RBP: 00007fc508ceec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd8b5634ef R14: 00007fc50620a300 R15: 0000000000022000
INFO: task syz-executor.3:11236 blocked for more than 144 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:29616 pid:11236 ppid:  6556 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc508c94a39
RSP: 002b:00007fc5061e9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc508d98020 RCX: 00007fc508c94a39
RDX: 0000000000000000 RSI: 0000000040047459 RDI: 0000000000000003
RBP: 00007fc508ceec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd8b5634ef R14: 00007fc5061e9300 R15: 0000000000022000
INFO: task syz-executor.3:11247 blocked for more than 144 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:28256 pid:11247 ppid:  6556 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc508c94a39
RSP: 002b:00007fc5061c8188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc508d980e0 RCX: 00007fc508c94a39
RDX: 00000000200000c0 RSI: 00000000c004743e RDI: 0000000000000003
RBP: 00007fc508ceec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd8b5634ef R14: 00007fc5061c8300 R15: 0000000000022000
INFO: task syz-executor.3:11248 blocked for more than 144 seconds.
      Not tainted 5.15.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:29616 pid:11248 ppid:  6556 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb44/0x5960 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc508c94a39
RSP: 002b:00007fc5061a7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc508d981a0 RCX: 00007fc508c94a39
RDX: 0000000000000000 RSI: 0000000040047459 RDI: 0000000000000003
RBP: 00007fc508ceec5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd8b5634ef R14: 00007fc5061a7300 R15: 0000000000022000

Showing all locks held in the system:
3 locks held by kworker/1:0/20:
 #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]
 #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]
 #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268
 #1: ffffc90000da7db0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272
 #2: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x83/0xe10 net/wireless/reg.c:2423
1 lock held by khungtaskd/27:
 #0: ffffffff8b981ee0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446
3 locks held by kworker/0:4/2971:
 #0: ffff888025b25138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888025b25138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888025b25138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff888025b25138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]
 #0: ffff888025b25138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]
 #0: ffff888025b25138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268
 #1: ffffc900010dfdb0 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272
 #2: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4590
1 lock held by in:imklog/6237:
1 lock held by syz-executor.0/11139:
 #0: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3be/0xb80 net/core/rtnetlink.c:5569
2 locks held by syz-executor.4/11166:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
 #1: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: ppp_create_interface drivers/net/ppp/ppp_generic.c:3323 [inline]
 #1: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1037 [inline]
 #1: ffffffff8d0e90e8 (rtnl_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x1876/0x2d50 drivers/net/ppp/ppp_generic.c:710
1 lock held by syz-executor.4/11174:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.4/11179:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.4/11237:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.4/11239:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.3/11231:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.3/11236:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.3/11247:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706
1 lock held by syz-executor.3/11248:
 #0: ffffffff8c6b5088 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8d/0x2d50 drivers/net/ppp/ppp_generic.c:706

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:295
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1689 Comm: kworker/u4:5 Not tainted 5.15.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: phy14 ieee80211_iface_work
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3683 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3702 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3757 [inline]
RIP: 0010:__lock_acquire+0x16ab/0x54a0 kernel/locking/lockdep.c:5015
Code: db 74 58 48 83 eb 08 74 52 48 ba 00 00 00 00 00 fc ff df eb 06 48 83 eb 08 74 40 48 8d 7b 18 48 89 f8 48 c1 e8 03 80 3c 10 00 <0f> 85 31 2a 00 00 48 8b 43 18 49 39 c7 0f 84 ec f5 ff ff 48 8d 7b
RSP: 0018:ffffc9000612f8a0 EFLAGS: 00000046
RAX: 1ffffffff1e247b7 RBX: ffffffff8f123da0 RCX: ffffffff815bed1f
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff8f123db8
RBP: 00000000000098c5 R08: 0000000000000000 R09: ffffffff8fd0c9e7
R10: fffffbfff1fa193c R11: 000000000000003f R12: ffff88801ef0a6f0
R13: ffff88801ef09c80 R14: 0000000000000000 R15: c044f723593cf9a9
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0c2b60c028 CR3: 000000000b68e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire kernel/locking/lockdep.c:5625 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
 __debug_check_no_obj_freed lib/debugobjects.c:980 [inline]
 debug_check_no_obj_freed+0xc7/0x420 lib/debugobjects.c:1023
 slab_free_hook mm/slub.c:1675 [inline]
 slab_free_freelist_hook+0xde/0x190 mm/slub.c:1725
 slab_free mm/slub.c:3483 [inline]
 kfree+0xe4/0x530 mm/slub.c:4543
 skb_free_head net/core/skbuff.c:653 [inline]
 skb_release_data+0x65a/0x790 net/core/skbuff.c:675
 skb_release_all net/core/skbuff.c:740 [inline]
 __kfree_skb net/core/skbuff.c:754 [inline]
 kfree_skb net/core/skbuff.c:772 [inline]
 kfree_skb+0x133/0x3f0 net/core/skbuff.c:766
 ieee80211_iface_work+0x411/0xd00 net/mac80211/iface.c:1495
 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
----------------
Code disassembly (best guess):
   0:	db 74 58 48          	(bad)  0x48(%rax,%rbx,2)
   4:	83 eb 08             	sub    $0x8,%ebx
   7:	74 52                	je     0x5b
   9:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  10:	fc ff df
  13:	eb 06                	jmp    0x1b
  15:	48 83 eb 08          	sub    $0x8,%rbx
  19:	74 40                	je     0x5b
  1b:	48 8d 7b 18          	lea    0x18(%rbx),%rdi
  1f:	48 89 f8             	mov    %rdi,%rax
  22:	48 c1 e8 03          	shr    $0x3,%rax
  26:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1)
* 2a:	0f 85 31 2a 00 00    	jne    0x2a61 <-- trapping instruction
  30:	48 8b 43 18          	mov    0x18(%rbx),%rax
  34:	49 39 c7             	cmp    %rax,%r15
  37:	0f 84 ec f5 ff ff    	je     0xfffff629
  3d:	48                   	rex.W
  3e:	8d                   	.byte 0x8d
  3f:	7b                   	.byte 0x7b

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/10/19 01:08 net-next-old f616447034a1 24dc29db .config console log report info ci-upstream-net-kasan-gce INFO: task hung in ppp_ioctl
* Struck through repros no longer work on HEAD.