INFO: task syz.2.35:6455 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.35 state:D stack:25736 pid:6455 tgid:6453 ppid:6241 task_flags:0x40054c flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1794/0x4c40 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x161/0x360 kernel/sched/core.c:7058 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:7115 rwsem_down_write_slowpath+0x922/0x10d0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1a7/0x1f0 kernel/locking/rwsem.c:1591 mmap_write_lock include/linux/mmap_lock.h:397 [inline] exit_mmap+0x28a/0xb10 mm/mmap.c:1288 __mmput+0x118/0x430 kernel/fork.c:1129 exit_mm+0x1d6/0x2b0 kernel/exit.c:582 do_exit+0x644/0x22f0 kernel/exit.c:949 do_group_exit+0x218/0x2d0 kernel/exit.c:1102 get_signal+0x125a/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x96/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x71/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x213/0x2e0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f6cd918eba9 RSP: 002b:00007f6cda0830e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f6cd93d5fa8 RCX: 00007f6cd918eba9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6cd93d5fa8 RBP: 00007f6cd93d5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6cd93d6038 R14: 00007fff2a49e4a0 R15: 00007fff2a49e588 INFO: task syz.2.35:6455 is blocked on an rw-semaphore, but the owner is not found. Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8db39620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8db39620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8db39620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2a/0x180 kernel/locking/lockdep.c:6775 2 locks held by klogd/5157: #0: ffff8880b8939f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:636 #1: ffff8880b8924008 (psi_seq){-.-.}-{0:0}, at: __slab_free+0x1b3/0x3b0 mm/slub.c:4541 2 locks held by udevd/5168: #0: ffffffff8dbf0790 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1484 [inline] #0: ffffffff8dbf0790 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1537 #1: ffff88807cce81e0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #1: ffff88807cce81e0 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x12a/0x1a90 mm/mmap.c:1727 2 locks held by getty/5560: #0: ffff88814d8ae0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43a/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/6136: #0: ffff88807bf6c260 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #0: ffff88807bf6c260 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x20d/0x4c0 mm/util.c:578 1 lock held by syz-executor/6239: #0: ffff88807aa6c260 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff88807aa6c260 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by syz-executor/6240: #0: ffff888030fa81e0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff888030fa81e0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by syz-executor/6244: #0: ffff888030fab7a0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff888030fab7a0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by syz-executor/6251: #0: ffff888030fa9760 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff888030fa9760 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by syz.2.35/6455: #0: ffff888027281760 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff888027281760 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by rm/6454: #0: ffff8880585ae2a0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #0: ffff8880585ae2a0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x20d/0x4c0 mm/util.c:578 1 lock held by udevd/7526: #0: ffff888078cf6d60 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #0: ffff888078cf6d60 (&mm->mmap_lock){++++}-{4:4}, at: __vm_munmap+0x158/0x3c0 mm/vma.c:3152 2 locks held by syz-executor/7531: #0: ffffffff8dbf0790 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1484 [inline] #0: ffffffff8dbf0790 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1537 #1: ffff888078cf37a0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #1: ffff888078cf37a0 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x12a/0x1a90 mm/mmap.c:1727 2 locks held by syz-executor/7552: #0: ffffffff8dbf0790 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1484 [inline] #0: ffffffff8dbf0790 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1537 #1: ffff888063e59760 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #1: ffff888063e59760 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x12a/0x1a90 mm/mmap.c:1727 1 lock held by syz.5.691/7864: #0: ffff8880272837a0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff8880272837a0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by syz.0.692/7865: #0: ffff888027284260 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff888027284260 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 1 lock held by syz.8.707/7902: #0: ffff888027969760 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:397 [inline] #0: ffff888027969760 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x28a/0xb10 mm/mmap.c:1288 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x185/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39a/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x176/0x2e0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0x15a7/0x15f0 kernel/hung_task.c:491 kthread+0x70a/0x890 kernel/kthread.c:463 ret_from_fork+0x431/0x7a0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: 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 08/18/2025 RIP: 0010:pv_native_safe_halt+0xb/0x20 arch/x86/kernel/paravirt.c:82 Code: 28 43 02 e9 47 e7 02 00 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 0f 00 2d 47 3f 1b 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 RSP: 0018:ffffffff8d807d80 EFLAGS: 000002c6 RAX: 945491592b7d6a00 RBX: ffffffff819506f4 RCX: 945491592b7d6a00 RDX: 0000000000000001 RSI: ffffffff8d2e0471 RDI: ffffffff8b7e7400 RBP: ffffffff8d807eb8 R08: ffff8880b8832f9b R09: 1ffff110171065f3 R10: dffffc0000000000 R11: ffffed10171065f4 R12: ffffffff8f35e070 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b128f0 FS: 0000000000000000(0000) GS:ffff88812669e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c0083fd010 CR3: 000000000d936000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0xf/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6e/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e4/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x40/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:744 start_kernel+0x3a5/0x400 init/main.c:1097 x86_64_start_reservations+0x20/0x20 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x13f/0x1c0 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x147