syzbot


INFO: task hung in mbind (2)

Status: auto-obsoleted due to no activity on 2026/05/17 12:06
Subsystems: mm
[Documentation on labels]
First crash: 97d, last: 95d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
13e5d32d-3ba8-4e24-b6f5-319698d3f415 assessment-security 💥 INFO: task hung in mbind (2) 2026/05/14 11:23 2026/05/14 11:23 2026/05/14 11:23 6ccb967e465e832a7bfd7a116ad00d52a0923a5d
failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128
From /app/workdir/repo/linux
 * branch                HEAD       -> FETCH_HEAD
Updating files:  ...
truncated to first 200 bytes; open job for full error
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in mbind mm 1 3 328d 337d 0/29 auto-obsoleted due to no activity on 2025/10/25 21:04

Sample crash report:
INFO: task syz.0.348:7225 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.348       state:D stack:26800 pid:7225  tgid:7220  ppid:5839   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_write_slowpath+0x883/0x1080 kernel/locking/rwsem.c:1215
 __down_write_common kernel/locking/rwsem.c:1347 [inline]
 __down_write kernel/locking/rwsem.c:1356 [inline]
 down_write+0x1bc/0x200 kernel/locking/rwsem.c:1626
 mmap_write_lock include/linux/mmap_lock.h:536 [inline]
 do_mbind mm/mempolicy.c:1529 [inline]
 kernel_mbind mm/mempolicy.c:1751 [inline]
 __do_sys_mbind mm/mempolicy.c:1825 [inline]
 __se_sys_mbind+0x995/0x10f0 mm/mempolicy.c:1821
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feb2cb9c799
RSP: 002b:00007feb2dafa028 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
RAX: ffffffffffffffda RBX: 00007feb2ce16090 RCX: 00007feb2cb9c799
RDX: 0000000000000000 RSI: 0000000000c00000 RDI: 0000200000000000
RBP: 00007feb2cc32c99 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feb2ce16128 R14: 00007feb2ce16090 R15: 00007ffd64c23ac8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:7/149:
 #0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x894/0x1780 kernel/workqueue.c:3261
 #1: ffffc90002ea7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1780 kernel/workqueue.c:3262
 #2: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by getty/5598:
 #0: ffff888037fef0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:11/6319:
 #0: ffff8880328a5140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x894/0x1780 kernel/workqueue.c:3261
 #1: ffffc900071a7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1780 kernel/workqueue.c:3262
 #2: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4198
1 lock held by syz.0.348/7225:
 #0: ffff88807e109c38 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:536 [inline]
 #0: ffff88807e109c38 (&mm->mmap_lock){++++}-{4:4}, at: do_mbind mm/mempolicy.c:1529 [inline]
 #0: ffff88807e109c38 (&mm->mmap_lock){++++}-{4:4}, at: kernel_mbind mm/mempolicy.c:1751 [inline]
 #0: ffff88807e109c38 (&mm->mmap_lock){++++}-{4:4}, at: __do_sys_mbind mm/mempolicy.c:1825 [inline]
 #0: ffff88807e109c38 (&mm->mmap_lock){++++}-{4:4}, at: __se_sys_mbind+0x995/0x10f0 mm/mempolicy.c:1821
2 locks held by syz.4.701/8589:
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
 #1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz.3.707/8612:
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink+0x42a/0x820 net/core/rtnetlink.c:3562
2 locks held by syz.1.704/8614:
 #0: ffff88807f58c440 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff88807f58c440 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x89/0x250 net/socket.c:724
 #1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
 #1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz.1.704/8616:
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3bc/0x1e30 drivers/net/tun.c:3078
1 lock held by syz.1.704/8620:
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x722/0xbe0 net/core/rtnetlink.c:6964
1 lock held by syz.1.704/8621:
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
1 lock held by syz.1.704/8622:
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:813

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0x1002/0x1060 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
vcan0: j1939_tp_rxtimer: 0xffff88802d1e2400: abort rx timeout. Force session deactivation
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:do_raw_spin_lock+0x1ab/0x2f0 kernel/locking/spinlock_debug.c:119
Code: 44 24 08 48 89 03 48 c7 44 24 20 0e 36 e0 45 4b c7 04 34 00 00 00 00 65 48 8b 05 30 6b 7b 11 48 3b 44 24 60 0f 85 3f 01 00 00 <48> 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 12 2c 14 0a cc e8 0c
RSP: 0018:ffffc90000007740 EFLAGS: 00000046
RAX: a0a7cd0654896e00 RBX: ffff8880b8628290 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007780
RBP: ffffc900000077e8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000ef0 R12: 1ffff92000000eec
R13: ffff8880b8628288 R14: dffffc0000000000 R15: 1ffff110170c5051
FS:  0000000000000000(0000) GS:ffff888125435000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555586ac94e8 CR3: 0000000032750000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1934 [inline]
 __hrtimer_run_queues+0x47b/0xa70 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x435/0x8e0 kernel/time/hrtimer.c:2112
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x450 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2039 [inline]
RIP: 0010:vprintk_emit+0x45d/0x560 kernel/printk/printk.c:2478
Code: 0f 84 44 ff ff ff e8 52 28 21 00 fb eb 44 e8 4a 28 21 00 e8 85 f8 0e 0a 4d 85 f6 74 94 e8 3b 28 21 00 fb 48 c7 c7 e0 fa 74 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 3b 17
RSP: 0018:ffffc90000007ae0 EFLAGS: 00000246
RAX: ffffffff81a58ae5 RBX: ffffffff81a5895f RCX: ffffffff8e492ec0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8e74fae0
RBP: ffffc90000007b90 R08: ffffffff90123ff7 R09: 1ffffffff20247fe
R10: dffffc0000000000 R11: fffffbfff20247ff R12: 0000000000000000
R13: 0000000000000059 R14: 0000000000000200 R15: 1ffff92000000f60
 _printk+0xdd/0x130 kernel/printk/printk.c:2504
 netdev_alert+0x11e/0x180 net/core/dev.c:13021
 j1939_tp_rxtimer+0x1cd/0x3d0 net/can/j1939/transport.c:1250
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x3d1/0xa70 kernel/time/hrtimer.c:1994
 hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2011
 handle_softirqs+0x22a/0x870 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:739
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:756
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: ed 6a 02 e9 d3 f1 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d b3 e1 14 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8e407dc0 EFLAGS: 00000242
RAX: 0000000000c6fb91 RBX: ffffffff819b946a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8df3af0d RDI: ffffffff8c284e00
RBP: ffffffff8e407eb0 R08: ffff8880b863399b R09: 1ffff110170c6733
R10: dffffc0000000000 R11: ffffed10170c6734 R12: 0000000000000000
R13: 1ffffffff1c925d8 R14: 0000000000000000 R15: 1ffffffff1c925d8
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
 rest_init+0x2de/0x300 init/main.c:762
 start_kernel+0x38f/0x3e0 init/main.c:1214
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/18 11:55 linux-next 8e5a478b6d6a 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/18 02:44 linux-next 8e5a478b6d6a c8810548 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/17 10:22 linux-next 95c541ddfb08 c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/16 12:39 linux-next b84a0ebe421c 64e21424 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/16 11:26 linux-next b84a0ebe421c 64e21424 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/15 17:41 linux-next b84a0ebe421c ee8d34d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/15 17:35 linux-next b84a0ebe421c ee8d34d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
2026/03/15 16:14 linux-next b84a0ebe421c ee8d34d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mbind
* Struck through repros no longer work on HEAD.