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INFO: task hung in synchronize_rcu

Status: premoderation: reported on 2025/06/24 05:11
Reported-by: syzbot+c4d24d6a458b9d101c09@syzkaller.appspotmail.com
First crash: 14h06m, last: 14h06m
▶ ▼ Similar bugs (12)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in synchronize_rcu (3) C done done 374 860d 1798d 22/29 fixed on 2023/02/24 13:50
linux-6.1 INFO: task hung in synchronize_rcu origin:lts-only C unreliable 18 22d 815d 0/3 upstream: reported C repro on 2023/04/01 04:49
android-49 INFO: task hung in synchronize_rcu 1 2034d 2034d 0/3 auto-closed as invalid on 2020/03/28 16:57
linux-4.14 INFO: task hung in synchronize_rcu vfs C error 162 874d 2056d 0/1 upstream: reported C repro on 2019/11/07 04:32
linux-4.19 INFO: task hung in synchronize_rcu C error 70 864d 2054d 0/1 upstream: reported C repro on 2019/11/08 21:27
linux-5.15 INFO: task hung in synchronize_rcu 1 800d 800d 0/3 auto-obsoleted due to no activity on 2023/08/14 02:05
linux-5.15 INFO: task hung in synchronize_rcu (3) origin:lts-only C error 13 75d 333d 0/3 upstream: reported C repro on 2024/07/26 03:55
upstream INFO: task hung in synchronize_rcu syz done 1206 2034d 2060d 14/29 fixed on 2019/11/29 15:48
upstream INFO: task hung in synchronize_rcu (4) net fs C done error 893 5d06h 782d 0/29 upstream: reported C repro on 2023/05/04 02:01
linux-5.15 INFO: task hung in synchronize_rcu (2) 1 489d 489d 0/3 auto-obsoleted due to no activity on 2024/05/31 13:53
android-414 INFO: task hung in synchronize_rcu 1 2052d 2052d 0/1 auto-closed as invalid on 2020/03/10 10:42
upstream INFO: task hung in synchronize_rcu (2) trace 8 2033d 2033d 0/29 closed as invalid on 2019/11/30 16:54

Sample crash report:
INFO: task kworker/0:3:448 blocked for more than 122 seconds.
      Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:3     state:D stack:0     pid:448   tgid:448   ppid:2      flags:0x00004000
Workqueue: events _RNvXs6_NtCs43vyB533jt3_6kernel9workqueueINtNtNtB7_4sync3arc3ArcNtNtCshgDM7dBCdno_11rust_binder7process7ProcessEINtB5_15WorkItemPointerKy0_E3runB13_
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion_state+0x19/0x40 kernel/sched/completion.c:264
 __wait_rcu_gp+0x296/0x2c0 kernel/rcu/update.c:514
 synchronize_rcu_normal+0x113/0x160 kernel/rcu/tree.c:4031
 synchronize_rcu+0x98/0x2e0 kernel/rcu/tree.c:4109
 core::ptr::drop_in_place::<kernel::sync::poll::PollCondVar> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::ptr::drop_in_place::<rust_binder::thread::Thread> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::ptr::drop_in_place::<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 <kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>, kernel::alloc::allocator::Kmalloc> as core::ops::drop::Drop>::drop rust/kernel/alloc/kbox.rs:487 [inline]
 core::ptr::drop_in_place::<kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>, kernel::alloc::allocator::Kmalloc>>+0x2ab/0x330 usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523
 core::mem::drop::<kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:935 [inline]
 <kernel::sync::arc::Arc<rust_binder::thread::Thread> as core::ops::drop::Drop>::drop rust/kernel/sync/arc.rs:404 [inline]
 core::ptr::drop_in_place::<kernel::sync::arc::Arc<rust_binder::thread::Thread>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::ptr::drop_in_place::<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 <kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>, kernel::alloc::allocator::Kmalloc> as core::ops::drop::Drop>::drop rust/kernel/alloc/kbox.rs:487 [inline]
 core::ptr::drop_in_place::<kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::mem::drop::<kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:935 [inline]
 <kernel::rbtree::RBTree<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>> as core::ops::drop::Drop>::drop rust/kernel/rbtree.rs:499 [inline]
 core::ptr::drop_in_place::<kernel::rbtree::RBTree<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>>+0xc5/0x190 usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523
 <rust_binder::process::Process>::deferred_release drivers/android/binder/process.rs:1367 [inline]
 <rust_binder::process::Process as kernel::workqueue::WorkItem>::run+0x243e/0x2860 drivers/android/binder/process.rs:483
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task syz.2.4508:13428 blocked for more than 123 seconds.
      Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.4508      state:D stack:0     pid:13428 tgid:13428 ppid:13247  flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion_state+0x19/0x40 kernel/sched/completion.c:264
 __wait_rcu_gp+0x296/0x2c0 kernel/rcu/update.c:514
 synchronize_rcu_normal+0x113/0x160 kernel/rcu/tree.c:4031
 synchronize_rcu+0x98/0x2e0 kernel/rcu/tree.c:4109
 rcu_sync_enter+0x1ec/0x340 kernel/rcu/sync.c:133
 percpu_down_write+0x76/0x600 kernel/locking/percpu-rwsem.c:255
 hci_uart_tty_close+0x108/0x230 drivers/bluetooth/hci_ldisc.c:548
 tty_ldisc_close drivers/tty/tty_ldisc.c:455 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:613 [inline]
 tty_ldisc_release+0x2ad/0x600 drivers/tty/tty_ldisc.c:781
 tty_release_struct+0x2d/0xe0 drivers/tty/tty_io.c:1690
 tty_release+0xc0a/0x1230 drivers/tty/tty_io.c:1861
 __fput+0x1fb/0xa00 fs/file_table.c:431
 ____fput+0x20/0x30 fs/file_table.c:459
 task_work_run+0x1e0/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9b4/0x2630 kernel/exit.c:944
 do_group_exit+0x22a/0x300 kernel/exit.c:1094
 get_signal+0x139d/0x14f0 kernel/signal.c:2934
 arch_do_signal_or_restart+0x96/0x720 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+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f244cdc11e5
RSP: 002b:00007f244db19f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f244cfb5fa0 RCX: 00007f244cdc11e5
RDX: 00007f244db19fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f244ce10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f244cfb5fa0 R15: 00007fffc42167a8
 </TASK>
INFO: task kworker/0:0:14607 blocked for more than 124 seconds.
      Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0     state:D stack:0     pid:14607 tgid:14607 ppid:2      flags:0x00004000
Workqueue: events _RNvXs6_NtCs43vyB533jt3_6kernel9workqueueINtNtNtB7_4sync3arc3ArcNtNtCshgDM7dBCdno_11rust_binder7process7ProcessEINtB5_15WorkItemPointerKy0_E3runB13_
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion_state+0x19/0x40 kernel/sched/completion.c:264
 __wait_rcu_gp+0x296/0x2c0 kernel/rcu/update.c:514
 synchronize_rcu_normal+0x113/0x160 kernel/rcu/tree.c:4031
 synchronize_rcu+0x98/0x2e0 kernel/rcu/tree.c:4109
 core::ptr::drop_in_place::<kernel::sync::poll::PollCondVar> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::ptr::drop_in_place::<rust_binder::thread::Thread> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::ptr::drop_in_place::<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 <kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>, kernel::alloc::allocator::Kmalloc> as core::ops::drop::Drop>::drop rust/kernel/alloc/kbox.rs:487 [inline]
 core::ptr::drop_in_place::<kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>, kernel::alloc::allocator::Kmalloc>>+0x2ab/0x330 usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523
 core::mem::drop::<kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder::thread::Thread>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:935 [inline]
 <kernel::sync::arc::Arc<rust_binder::thread::Thread> as core::ops::drop::Drop>::drop rust/kernel/sync/arc.rs:404 [inline]
 core::ptr::drop_in_place::<kernel::sync::arc::Arc<rust_binder::thread::Thread>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::ptr::drop_in_place::<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 <kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>, kernel::alloc::allocator::Kmalloc> as core::ops::drop::Drop>::drop rust/kernel/alloc/kbox.rs:487 [inline]
 core::ptr::drop_in_place::<kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523 [inline]
 core::mem::drop::<kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:935 [inline]
 <kernel::rbtree::RBTree<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>> as core::ops::drop::Drop>::drop rust/kernel/rbtree.rs:499 [inline]
 core::ptr::drop_in_place::<kernel::rbtree::RBTree<i32, kernel::sync::arc::Arc<rust_binder::thread::Thread>>>+0xc5/0x190 usr/local/rustup/toolchains/1.87.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:523
 <rust_binder::process::Process>::deferred_release drivers/android/binder/process.rs:1367 [inline]
 <rust_binder::process::Process as kernel::workqueue::WorkItem>::run+0x243e/0x2860 drivers/android/binder/process.rs:483
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task syz.2.4887:14615 blocked for more than 124 seconds.
      Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.4887      state:D stack:0     pid:14615 tgid:14615 ppid:13247  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 rcu_barrier+0x415/0x530 kernel/rcu/tree.c:4642
 kvm_mmu_uninit_tdp_mmu+0x1df/0x210 arch/x86/kvm/mmu/tdp_mmu.c:51
 kvm_mmu_uninit_vm+0x27/0x60 arch/x86/kvm/mmu/mmu.c:6572
 kvm_arch_destroy_vm+0x383/0x410 arch/x86/kvm/x86.c:12898
 kvm_destroy_vm virt/kvm/kvm_main.c:1355 [inline]
 kvm_put_kvm+0xb04/0x12b0 virt/kvm/kvm_main.c:1391
 kvm_vm_release+0x47/0x70 virt/kvm/kvm_main.c:1414
 __fput+0x1fb/0xa00 fs/file_table.c:431
 ____fput+0x20/0x30 fs/file_table.c:459
 task_work_run+0x1e0/0x250 kernel/task_work.c:240
 resume_user_mode_work+0x36/0x50 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x64/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f244cd8e929
RSP: 002b:00007fffc4216908 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f244cfb7ba0 RCX: 00007f244cd8e929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f244cfb7ba0 R08: 0000000000000210 R09: 0000001ec4216bff
R10: 00007f244cfb7ac0 R11: 0000000000000246 R12: 000000000006d041
R13: 00007f244cfb5fa0 R14: ffffffffffffffff R15: 00007fffc4216a20
 </TASK>
INFO: task syz.9.4891:14625 blocked for more than 126 seconds.
      Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.4891      state:D stack:0     pid:14625 tgid:14618 ppid:11080  flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion_state+0x19/0x40 kernel/sched/completion.c:264
 __wait_rcu_gp+0x296/0x2c0 kernel/rcu/update.c:514
 synchronize_rcu_normal+0x113/0x160 kernel/rcu/tree.c:4031
 synchronize_rcu+0x98/0x2e0 kernel/rcu/tree.c:4109
 synchronize_net+0x38/0x40 net/core/dev.c:11366
 packet_release+0x9f8/0xd50 net/packet/af_packet.c:3217
 __sock_release net/socket.c:659 [inline]
 sock_close+0xda/0x280 net/socket.c:1427
 __fput+0x1fb/0xa00 fs/file_table.c:431
 ____fput+0x20/0x30 fs/file_table.c:459
 task_work_run+0x1e0/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9b4/0x2630 kernel/exit.c:944
 do_group_exit+0x22a/0x300 kernel/exit.c:1094
 get_signal+0x139d/0x14f0 kernel/signal.c:2934
 arch_do_signal_or_restart+0x96/0x720 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+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f46f3d8e929
RSP: 002b:00007f46f23d60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f46f3fb6168 RCX: 00007f46f3d8e929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f46f3fb6168
RBP: 00007f46f3fb6160 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f46f3fb616c
R13: 0000000000000000 R14: 00007ffefc1c5f00 R15: 00007ffefc1c5fe8
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0 c93aecf919cd453af8c9b0d1ce6d9747cbb4dbdf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:229 [inline]
 watchdog+0xd8f/0xed0 kernel/hung_task.c:385
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 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: 20 Comm: rcuop/0 Not tainted 6.12.30-syzkaller-g1d4f4d446dbd #0 c93aecf919cd453af8c9b0d1ce6d9747cbb4dbdf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x90 kernel/kcov.c:313
Code: 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 5d c3 cc cc cc cc cc 66 90 b8 6e b2 04 de 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 48 8b 45 08 65 48 8b 14 25 40 e9 04 00 65
RSP: 0018:ffffc90000230040 EFLAGS: 00000202
RAX: ffffffff8460aba2 RBX: ffff888164c3c8c0 RCX: 0000000000000100
RDX: ffff888103660000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc90000230070 R08: ffff888164c3c9b7 R09: 1ffff1102c987936
R10: dffffc0000000000 R11: ffffed102c987937 R12: 00000000fffc0001
R13: 0000000000000001 R14: 0000000000000001 R15: ffff888125d60000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd7a0aecdc CR3: 000000010b77e000 CR4: 00000000003526b0
DR0: 0000800000000000 DR1: 0000000000000008 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 packet_rcv+0x180/0x1670 net/packet/af_packet.c:2276
 dev_queue_xmit_nit+0xa3d/0xae0 net/core/dev.c:2418
 xmit_one net/core/dev.c:3655 [inline]
 dev_hard_start_xmit+0x187/0x770 net/core/dev.c:3678
 __dev_queue_xmit+0x19cc/0x3790 net/core/dev.c:4514
 dev_queue_xmit include/linux/netdevice.h:3141 [inline]
 br_dev_queue_push_xmit+0x553/0x6d0 net/bridge/br_forward.c:53
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_forward_finish net/bridge/br_forward.c:66 [inline]
 NF_HOOK include/linux/netfilter.h:317 [inline]
 __br_forward+0x25c/0x390 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver net/bridge/br_forward.c:190 [inline]
 br_flood+0x50e/0x730 net/bridge/br_forward.c:236
 br_handle_frame_finish+0x12bb/0x1720 net/bridge/br_input.c:215
 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
 br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xf4b/0x3940 net/core/dev.c:5651
 __netif_receive_skb_one_core net/core/dev.c:5755 [inline]
 __netif_receive_skb net/core/dev.c:5870 [inline]
 process_backlog+0x3e5/0xae0 net/core/dev.c:6202
 __napi_poll+0xd3/0x610 net/core/dev.c:6853
 napi_poll net/core/dev.c:6922 [inline]
 net_rx_action+0x584/0xce0 net/core/dev.c:7044
 handle_softirqs+0x1ae/0x630 kernel/softirq.c:603
 __do_softirq+0xf/0x16 kernel/softirq.c:641
 do_softirq+0xa6/0x100 kernel/softirq.c:485
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:412
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_do_batch+0x5c6/0xd20 kernel/rcu/tree.c:2586
 nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
 rcu_nocb_cb_kthread+0x4dc/0xac0 kernel/rcu/tree_nocb.h:957
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/24 05:10 android16-6.12 1d4f4d446dbd e2f27c35 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in synchronize_rcu
* Struck through repros no longer work on HEAD.