syzbot


INFO: task hung in synchronize_rcu (2)

Status: premoderation: reported on 2026/02/14 17:59
Reported-by: syzbot+f8eb01353cd131dd7b63@syzkaller.appspotmail.com
First crash: 13d, last: 3d14h
Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in synchronize_rcu (3) 1 C done done 374 1108d 2046d 22/29 fixed on 2023/02/24 13:50
linux-6.1 INFO: task hung in synchronize_rcu origin:lts-only 1 C unreliable 26 55d 1063d 0/3 upstream: reported C repro on 2023/04/01 04:49
android-49 INFO: task hung in synchronize_rcu 1 1 2282d 2282d 0/3 auto-closed as invalid on 2020/03/28 16:57
linux-4.14 INFO: task hung in synchronize_rcu vfs 1 C error 162 1122d 2304d 0/1 upstream: reported C repro on 2019/11/07 04:32
linux-4.19 INFO: task hung in synchronize_rcu 1 C error 70 1112d 2302d 0/1 upstream: reported C repro on 2019/11/08 21:27
linux-5.15 INFO: task hung in synchronize_rcu 1 1 1048d 1048d 0/3 auto-obsoleted due to no activity on 2023/08/14 02:05
android-6-12 INFO: task hung in synchronize_rcu 1 41 107d 230d 0/1 auto-obsoleted due to no activity on 2026/01/01 15:51
linux-5.15 INFO: task hung in synchronize_rcu (3) origin:lts-only 1 C error 18 6d13h 581d 0/3 upstream: reported C repro on 2024/07/26 03:55
upstream INFO: task hung in synchronize_rcu 1 syz done 1206 2282d 2308d 14/29 fixed on 2019/11/29 15:48
upstream INFO: task hung in synchronize_rcu (4) net fs 1 C done error 2552 6d14h 1030d 0/29 upstream: reported C repro on 2023/05/04 02:01
linux-5.15 INFO: task hung in synchronize_rcu (2) 1 1 737d 737d 0/3 auto-obsoleted due to no activity on 2024/05/31 13:53
android-414 INFO: task hung in synchronize_rcu 1 1 2300d 2300d 0/1 auto-closed as invalid on 2020/03/10 10:42
upstream INFO: task hung in synchronize_rcu (2) trace 1 8 2281d 2281d 0/29 closed as invalid on 2019/11/30 16:54
linux-6.6 INFO: task hung in synchronize_rcu 1 4 42d 120d 0/2 upstream: reported on 2025/10/30 17:16
upstream INFO: task hung in rtnetlink_rcv_msg net 1 C inconclusive inconclusive 1970 598d 2562d 26/29 fixed on 2024/07/09 19:14

Sample crash report:
INFO: task syz-executor:290 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:290   tgid:290   ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 exp_funnel_lock kernel/rcu/tree_exp.h:331 [inline]
 synchronize_rcu_expedited+0x296/0x970 kernel/rcu/tree_exp.h:978
 namespace_unlock+0x248/0x430 fs/namespace.c:1710
 do_umount fs/namespace.c:1937 [inline]
 path_umount+0xecd/0xf50 fs/namespace.c:2020
 ksys_umount fs/namespace.c:2043 [inline]
 __do_sys_umount fs/namespace.c:2048 [inline]
 __se_sys_umount fs/namespace.c:2046 [inline]
 __x64_sys_umount+0x12e/0x180 fs/namespace.c:2046
 x64_sys_call+0x2ab8/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:167
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f3aa3f9d897
RSP: 002b:00007ffe54fee528 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f3aa4031ef0 RCX: 00007f3aa3f9d897
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe54fee5e0
RBP: 00007ffe54fee5e0 R08: 00007ffe54fef5e0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe54fef670
R13: 00007f3aa4031ef0 R14: 0000000000000005 R15: 00007ffe54fef6b0
 </TASK>
INFO: task kworker/1:5:575 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:5     state:D stack:0     pid:575   tgid:575   ppid:2      flags:0x00004000
Workqueue: events _RNSNvXs6_NtCs1ewLyjEZ7Le_6kernel9workqueueINtNtNtB9_4sync3arc3ArcNtNtCskDQVOo9v79Q_16rust_binder_main7process7ProcessEINtB7_15WorkItemPointerKy0_E3run11reify_fnptrB15_
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 synchronize_rcu_expedited+0x6eb/0x970 kernel/rcu/tree_exp.h:994
 synchronize_rcu+0x77/0x2f0 kernel/rcu/tree.c:4119
 core::ptr::drop_in_place::<kernel::sync::poll::PollCondVar> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 core::ptr::drop_in_place::<rust_binder_main::thread::Thread> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 core::ptr::drop_in_place::<kernel::sync::arc::ArcInner<rust_binder_main::thread::Thread>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 <kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder_main::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_main::thread::Thread>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 core::mem::drop::<kernel::alloc::kbox::Box<kernel::sync::arc::ArcInner<rust_binder_main::thread::Thread>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:961 [inline]
 <kernel::sync::arc::Arc<rust_binder_main::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_main::thread::Thread>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 core::ptr::drop_in_place::<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder_main::thread::Thread>>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 <kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder_main::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_main::thread::Thread>>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804 [inline]
 core::mem::drop::<kernel::alloc::kbox::Box<kernel::rbtree::Node<i32, kernel::sync::arc::Arc<rust_binder_main::thread::Thread>>, kernel::alloc::allocator::Kmalloc>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:961 [inline]
 <kernel::rbtree::RBTree<i32, kernel::sync::arc::Arc<rust_binder_main::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_main::thread::Thread>>>+0x466/0x8e0 usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:804
 core::mem::drop::<kernel::rbtree::RBTree<i32, kernel::sync::arc::Arc<rust_binder_main::thread::Thread>>> usr/local/rustup/toolchains/1.91.1-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:961 [inline]
 <rust_binder_main::process::Process>::deferred_release drivers/android/binder/process.rs:1439 [inline]
 <rust_binder_main::process::Process as kernel::workqueue::WorkItem>::run+0x2984/0x3310 drivers/android/binder/process.rs:509
 <kernel::sync::arc::Arc<rust_binder_main::process::Process> as kernel::workqueue::WorkItemPointer<0>>::run rust/kernel/workqueue.rs:536 [inline]
 <kernel::sync::arc::Arc<rust_binder_main::process::Process> as kernel::workqueue::WorkItemPointer<0>>::run::{shim:reify_fnptr#0}+0x98/0x170 rust/kernel/workqueue.rs:528
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400
 kthread+0x2c9/0x370 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 kworker/u8:24:1215 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:24   state:D stack:0     pid:1215  tgid:1215  ppid:2      flags:0x00004000
Workqueue: events_unbound fsnotify_mark_destroy_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x369/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 __synchronize_srcu kernel/rcu/srcutree.c:1401 [inline]
 synchronize_srcu_expedited+0x20b/0x290 kernel/rcu/srcutree.c:1426
 synchronize_srcu+0x2c3/0x4c0 kernel/rcu/srcutree.c:1480
 fsnotify_mark_destroy_workfn+0x10a/0x310 fs/notify/mark.c:988
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400
 kthread+0x2c9/0x370 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 kworker/u8:31:1222 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:31   state:D stack:0     pid:1222  tgid:1222  ppid:2      flags:0x00004000
Workqueue: events_unbound fsnotify_connector_destroy_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x369/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 __synchronize_srcu kernel/rcu/srcutree.c:1401 [inline]
 synchronize_srcu_expedited+0x20b/0x290 kernel/rcu/srcutree.c:1426
 synchronize_srcu+0x2c3/0x4c0 kernel/rcu/srcutree.c:1480
 fsnotify_connector_destroy_workfn+0x48/0xb0 fs/notify/mark.c:318
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400
 kthread+0x2c9/0x370 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.3.1323:4404 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1323      state:D stack:0     pid:4404  tgid:4404  ppid:293    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 synchronize_rcu_expedited+0x517/0x970 kernel/rcu/tree_exp.h:978
 namespace_unlock+0x248/0x430 fs/namespace.c:1710
 dissolve_on_fput+0xcf/0x110 fs/namespace.c:2227
 __fput+0x86a/0xa00 fs/file_table.c:439
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e5/0x260 kernel/task_work.c:246
 resume_user_mode_work+0x35/0x50 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+0x63/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fe462b9c629
RSP: 002b:00007ffc1de8e768 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc1de8e850 RCX: 00007fe462b9c629
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000002fe0b R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2e120000 R11: 0000000000000246 R12: 00007ffc1de8e890
R13: 00007fe462e15fac R14: 000000000002fe41 R15: 00007fe462e15fa0
 </TASK>
INFO: task syz.4.1325:4408 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1325      state:D stack:0     pid:4408  tgid:4408  ppid:2462   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x369/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 __flush_work+0x712/0xb10 kernel/workqueue.c:4233
 flush_work kernel/workqueue.c:4255 [inline]
 flush_delayed_work+0x8f/0xb0 kernel/workqueue.c:4277
 fsnotify_wait_marks_destroyed+0x19/0x20 fs/notify/mark.c:999
 fsnotify_destroy_group+0x21b/0x350 fs/notify/group.c:76
 inotify_release+0x3c/0x50 fs/notify/inotify/inotify_user.c:308
 __fput+0x1fb/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e5/0x260 kernel/task_work.c:246
 resume_user_mode_work+0x35/0x50 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+0x63/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f21b279c629
RSP: 002b:00007ffec99b3bf8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f21b2a17da0 RCX: 00007f21b279c629
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f21b2a17da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f21b2a17cb0 R11: 0000000000000246 R12: 0000000000030951
R13: 00007f21b2a1609c R14: 00000000000306ab R15: 00007f21b2a16090
 </TASK>
INFO: task syz.4.1325:4409 blocked for more than 125 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1325      state:D stack:0     pid:4409  tgid:4408  ppid:2462   flags:0x00000006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 synchronize_rcu_expedited+0x517/0x970 kernel/rcu/tree_exp.h:978
 kern_unmount_array+0x2ea/0x420 fs/namespace.c:5681
 ovl_free_fs+0x3fe/0x6d0 fs/overlayfs/params.c:739
 ovl_fill_super+0x3690/0x38f0 fs/overlayfs/super.c:1476
 vfs_get_super fs/super.c:1286 [inline]
 get_tree_nodev+0xcb/0x170 fs/super.c:1305
 ovl_get_tree+0x20/0x30 fs/overlayfs/params.c:610
 vfs_get_tree+0x9e/0x290 fs/super.c:1820
 do_new_mount+0x251/0xb30 fs/namespace.c:3557
 path_mount+0x682/0x1010 fs/namespace.c:3884
 do_mount fs/namespace.c:3897 [inline]
 __do_sys_mount fs/namespace.c:4107 [inline]
 __se_sys_mount+0x2bf/0x480 fs/namespace.c:4084
 __x64_sys_mount+0xc3/0xf0 fs/namespace.c:4084
 x64_sys_call+0x2021/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f21b279c629
RSP: 002b:00007f21b36d7028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f21b2a15fa0 RCX: 00007f21b279c629
RDX: 0000200000000080 RSI: 00002000000000c0 RDI: 0000000000000000
RBP: 00007f21b2832b39 R08: 0000200000000180 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21b2a16038 R14: 00007f21b2a15fa0 R15: 00007ffec99b3a98
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 ec67a0b9c3f9090985a335a00964337a606b4ed6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/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:267 [inline]
 watchdog+0xdad/0xf00 kernel/hung_task.c:423
 kthread+0x2c9/0x370 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 1 to CPUs 0:
watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.1.1316:4391]
CPU#0 Utilization every 22s during lockup:
	#1: 100% system,	  1% softirq,	  1% hardirq,	  0% idle
	#2: 100% system,	  0% softirq,	  1% hardirq,	  0% idle
	#3: 100% system,	  1% softirq,	  1% hardirq,	  0% idle
	#4: 100% system,	  1% softirq,	  1% hardirq,	  0% idle
	#5: 100% system,	  1% softirq,	  1% hardirq,	  0% idle
Modules linked in:
CPU: 0 UID: 0 PID: 4391 Comm: syz.1.1316 Not tainted syzkaller #0 ec67a0b9c3f9090985a335a00964337a606b4ed6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:430 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x7cb/0xe90 kernel/locking/qspinlock.c:508
Code: ff ff c6 44 16 06 02 66 c7 84 24 90 00 00 00 00 01 48 8b 44 24 48 0f b6 04 10 84 c0 75 5c 80 3f 00 74 0e c6 44 16 06 f8 f3 90 <41> ff c5 75 d3 eb 6d be 02 00 00 00 e8 f4 8a 3e fc 48 8d bc 24 90
RSP: 0018:ffffc9000f234260 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffc9000f234300 RCX: ffff88811afa1300
RDX: dffffc0000000000 RSI: 1ffff92001e46858 RDI: ffff88811bb98088
RBP: ffffc9000f234370 R08: ffff88811bb98088 R09: 1ffff11023773011
R10: dffffc0000000000 R11: ffffed1023773012 R12: 0000000000000000
R13: 00000000ffff966a R14: 1ffff11023773011 R15: 1ffffffff0e9cdf9
FS:  00007f8a321c26c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8a321a0ff8 CR3: 000000012be5a000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 000000000000ff40
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
 _raw_spin_lock+0x115/0x120 kernel/locking/spinlock.c:154
 <kernel::sync::lock::Lock<rust_binder_main::process::ProcessInner, kernel::sync::lock::spinlock::SpinLockBackend>>::lock rust/kernel/sync/lock.rs:142 [inline]
 <rust_binder_main::process::Process>::push_work drivers/android/binder/process.rs:730 [inline]
 <rust_binder_main::thread::Thread>::push_work_if_looper+0x202/0x620 drivers/android/binder/thread.rs:667
 <rust_binder_main::node::NodeDeath>::set_notification_done drivers/android/binder/node.rs:1044 [inline]
 <rust_binder_main::process::Process>::dead_binder_done drivers/android/binder/process.rs:1312 [inline]
 <rust_binder_main::thread::Thread>::write+0x3aa3/0xa690 drivers/android/binder/thread.rs:1505
 <rust_binder_main::thread::Thread>::write_read drivers/android/binder/thread.rs:1608 [inline]
 <rust_binder_main::process::Process>::ioctl_write_read drivers/android/binder/process.rs:1609 [inline]
 <rust_binder_main::process::Process>::ioctl drivers/android/binder/process.rs:1674 [inline]
 rust_binder_main::rust_binder_ioctl+0x1077/0x5da0 drivers/android/binder/rust_binder_main.rs:449
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x135/0x1b0 fs/ioctl.c:893
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:893
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f8a3379c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8a321c2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8a33a16090 RCX: 00007f8a3379c629
RDX: 0000200000000040 RSI: 00000000c0306201 RDI: 0000000000000004
RBP: 00007f8a33832b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8a33a16128 R14: 00007f8a33a16090 R15: 00007ffecdf201c8
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 4391 Comm: syz.1.1316 Tainted: G             L     syzkaller #0 ec67a0b9c3f9090985a335a00964337a606b4ed6
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:430 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x7cb/0xe90 kernel/locking/qspinlock.c:508
Code: ff ff c6 44 16 06 02 66 c7 84 24 90 00 00 00 00 01 48 8b 44 24 48 0f b6 04 10 84 c0 75 5c 80 3f 00 74 0e c6 44 16 06 f8 f3 90 <41> ff c5 75 d3 eb 6d be 02 00 00 00 e8 f4 8a 3e fc 48 8d bc 24 90
RSP: 0018:ffffc9000f234260 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffc9000f234300 RCX: ffff88811afa1300
RDX: dffffc0000000000 RSI: 1ffff92001e46858 RDI: ffff88811bb98088
RBP: ffffc9000f234370 R08: ffff88811bb98088 R09: 1ffff11023773011
R10: dffffc0000000000 R11: ffffed1023773012 R12: 0000000000000000
R13: 00000000ffffbf18 R14: 1ffff11023773011 R15: 1ffffffff0e9cdf9
FS:  00007f8a321c26c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8a321a0ff8 CR3: 000000012be5a000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 000000000000ff40
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
 _raw_spin_lock+0x115/0x120 kernel/locking/spinlock.c:154
 <kernel::sync::lock::Lock<rust_binder_main::process::ProcessInner, kernel::sync::lock::spinlock::SpinLockBackend>>::lock rust/kernel/sync/lock.rs:142 [inline]
 <rust_binder_main::process::Process>::push_work drivers/android/binder/process.rs:730 [inline]
 <rust_binder_main::thread::Thread>::push_work_if_looper+0x202/0x620 drivers/android/binder/thread.rs:667
 <rust_binder_main::node::NodeDeath>::set_notification_done drivers/android/binder/node.rs:1044 [inline]
 <rust_binder_main::process::Process>::dead_binder_done drivers/android/binder/process.rs:1312 [inline]
 <rust_binder_main::thread::Thread>::write+0x3aa3/0xa690 drivers/android/binder/thread.rs:1505
 <rust_binder_main::thread::Thread>::write_read drivers/android/binder/thread.rs:1608 [inline]
 <rust_binder_main::process::Process>::ioctl_write_read drivers/android/binder/process.rs:1609 [inline]
 <rust_binder_main::process::Process>::ioctl drivers/android/binder/process.rs:1674 [inline]
 rust_binder_main::rust_binder_ioctl+0x1077/0x5da0 drivers/android/binder/rust_binder_main.rs:449
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x135/0x1b0 fs/ioctl.c:893
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:893
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f8a3379c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8a321c2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8a33a16090 RCX: 00007f8a3379c629
RDX: 0000200000000040 RSI: 00000000c0306201 RDI: 0000000000000004
RBP: 00007f8a33832b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8a33a16128 R14: 00007f8a33a16090 R15: 00007ffecdf201c8
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/24 04:26 android16-6.12 569fa7be00d7 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in synchronize_rcu
2026/02/22 15:12 android16-6.12 c190014704c7 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in synchronize_rcu
2026/02/22 14:59 android16-6.12 c190014704c7 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in synchronize_rcu
2026/02/14 17:58 android16-6.12 837ec018b485 1e62d198 .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.