rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=18fc/1/0x4000000000000000 softirq=30918/30919 fqs=17 rcu: (detected by 0, t=10506 jiffies, g=39329, q=283 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 12 Comm: kworker/u4:1 Not tainted 6.6.99-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_release kernel/locking/lockdep.c:5408 [inline] RIP: 0010:lock_release+0x15c/0x8b0 kernel/locking/lockdep.c:5774 Code: 00 9c 8f 84 24 a0 00 00 00 48 8b 84 24 a0 00 00 00 48 89 44 24 50 fa 48 c7 c7 20 c7 aa 8a e8 7b a2 05 09 65 ff 05 1c fe 9a 7e 44 24 5c 01 00 00 00 48 c7 c0 9c b1 4a 8e 48 c1 e8 03 42 0f b6 RSP: 0018:ffffc900001f0a20 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff88801ba564dc RCX: 4671086f5fbabb00 RDX: 0000000000000000 RSI: ffffffff8aaac720 RDI: ffffffff8afc6680 RBP: ffffc900001f0b30 R08: ffffffff8e4a7cef R09: 1ffffffff1c94f9d R10: dffffc0000000000 R11: fffffbfff1c94f9e R12: ffffffff842548b3 R13: dffffc0000000000 R14: ffff88801ba55a00 R15: 1ffff9200003e150 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff42399ff8 CR3: 000000004e1ff000 CR4: 00000000003506e0 Call Trace: debug_objects_fill_pool+0xb3/0x6b0 lib/debugobjects.c:617 debug_object_activate+0x36/0x4b0 lib/debugobjects.c:705 debug_hrtimer_activate kernel/time/hrtimer.c:450 [inline] debug_activate kernel/time/hrtimer.c:505 [inline] enqueue_hrtimer+0x30/0x370 kernel/time/hrtimer.c:1113 __run_hrtimer kernel/time/hrtimer.c:1772 [inline] __hrtimer_run_queues+0x637/0xc40 kernel/time/hrtimer.c:1819 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc90000117a40 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 4671086f5fbabb00 RDX: 0000000000000000 RSI: ffffffff8aaacbc0 RDI: ffffffff8afc6680 RBP: ffffc90000117b48 R08: dffffc0000000000 R09: 1ffffffff21b44a4 R10: dffffc0000000000 R11: fffffbfff21b44a5 R12: 1ffff92000022f54 R13: ffffffff8cd2fba0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xef/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: rcu_preempt kthread starved for 10420 jiffies! g39329 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:26920 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 9223 Comm: syz.3.1169 Not tainted 6.6.99-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x45/0x60 kernel/kcov.c:221 Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 RSP: 0018:ffffc90003087658 EFLAGS: 00000246 RAX: ffffffff817ac327 RBX: 1ffff110171e82f5 RCX: ffff8880278f3c00 RDX: ffffc9000cf2a000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc900030877c8 R08: ffffffff90da257f R09: 1ffffffff21b44af R10: dffffc0000000000 R11: fffffbfff21b44b0 R12: ffff8880b8f417a8 R13: dffffc0000000000 R14: ffff8880b8e3d588 R15: 0000000000000001 FS: 00007fbd6f5856c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbd6e771de0 CR3: 000000004e1ff000 CR4: 00000000003506f0 Call Trace: csd_lock_wait kernel/smp.c:311 [inline] smp_call_function_many_cond+0xdf7/0x1130 kernel/smp.c:855 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023 kill_bdev block/bdev.c:75 [inline] blkdev_flush_mapping+0x128/0x290 block/bdev.c:632 blkdev_put_whole block/bdev.c:663 [inline] blkdev_put+0x498/0x760 block/bdev.c:941 btrfs_scan_one_device+0x266/0x610 fs/btrfs/volumes.c:1456 btrfs_mount_root+0x49a/0x920 fs/btrfs/super.c:1489 legacy_get_tree+0xea/0x180 fs/fs_context.c:662 vfs_get_tree+0x8c/0x280 fs/super.c:1764 fc_mount fs/namespace.c:1108 [inline] vfs_kern_mount+0xbe/0x160 fs/namespace.c:1138 btrfs_mount+0x2e1/0xa70 fs/btrfs/super.c:1587 legacy_get_tree+0xea/0x180 fs/fs_context.c:662 vfs_get_tree+0x8c/0x280 fs/super.c:1764 do_new_mount+0x24b/0xa40 fs/namespace.c:3366 do_mount fs/namespace.c:3706 [inline] __do_sys_mount fs/namespace.c:3915 [inline] __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fbd6e79014a Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fbd6f584e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fbd6f584ef0 RCX: 00007fbd6e79014a RDX: 00002000000055c0 RSI: 0000200000000040 RDI: 00007fbd6f584eb0 RBP: 00002000000055c0 R08: 00007fbd6f584ef0 R09: 0000000000000008 R10: 0000000000000008 R11: 0000000000000246 R12: 0000200000000040 R13: 00007fbd6f584eb0 R14: 00000000000055ae R15: 0000200000000240