rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P58/1:b..l rcu: (detected by 1, t=10502 jiffies, g=5345, q=700 ncpus=2) task:kworker/u4:4 state:R running task stack:25808 pid:58 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7022 irqentry_exit+0x35/0x80 kernel/entry/common.c:433 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5729 Code: c1 05 d5 6e 9b 7e 83 f8 01 0f 85 b0 02 00 00 9c 58 f6 c4 02 0f 85 9b 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90001597ac8 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920002b2f5b RCX: 0000000000000001 RDX: 1ffff110031d0158 RSI: ffffffff8a6c83a0 RDI: ffffffff8ac81200 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2309dd0 R10: ffffffff9184ee87 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8c9a7400 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:303 [inline] rcu_read_lock include/linux/rcupdate.h:749 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x175/0x10f0 net/batman-adv/network-coding.c:719 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: rcu_preempt kthread starved for 10528 jiffies! g5345 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:28320 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 schedule+0xe7/0x1b0 kernel/sched/core.c:6786 schedule_timeout+0x157/0x2c0 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xa50 kernel/rcu/tree.c:1609 rcu_gp_kthread+0x249/0x380 kernel/rcu/tree.c:1808 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 5167 Comm: syz-executor.3 Not tainted 6.5.0-rc7-syzkaller-00144-g4942fed84b98 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5729 Code: c1 05 d5 6e 9b 7e 83 f8 01 0f 85 b0 02 00 00 9c 58 f6 c4 02 0f 85 9b 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90004f4f3e8 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920009e9e7f RCX: 0000000000000001 RDX: 1ffff11004375158 RSI: ffffffff8a6c83a0 RDI: ffffffff8ac81200 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2309dd0 R10: ffffffff9184ee87 R11: 0000000000094000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8c9a7400 R15: 0000000000000000 FS: 00007f6af11ff6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000485750 CR3: 000000006804b000 CR4: 0000000000350ee0 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] rcu_read_lock include/linux/rcupdate.h:749 [inline] percpu_ref_tryget_many.constprop.0+0x38/0x2c0 include/linux/percpu-refcount.h:241 percpu_ref_tryget include/linux/percpu-refcount.h:266 [inline] wb_tryget include/linux/backing-dev-defs.h:217 [inline] wb_get_create_current include/linux/backing-dev.h:228 [inline] balance_dirty_pages_ratelimited_flags+0xdf7/0x1230 mm/page-writeback.c:2006 generic_perform_write+0x38b/0x600 mm/filemap.c:3957 ext4_buffered_write_iter+0x11f/0x3c0 fs/ext4/file.c:299 ext4_file_write_iter+0x7ee/0x1950 fs/ext4/file.c:722 call_write_iter include/linux/fs.h:1877 [inline] do_iter_readv_writev+0x21e/0x3c0 fs/read_write.c:735 do_iter_write+0x17f/0x830 fs/read_write.c:860 vfs_iter_write+0x7a/0xb0 fs/read_write.c:901 iter_file_splice_write+0x698/0xbf0 fs/splice.c:739 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x118/0x180 fs/splice.c:1145 splice_direct_to_actor+0x347/0xa30 fs/splice.c:1091 do_splice_direct+0x1af/0x280 fs/splice.c:1197 do_sendfile+0xb88/0x1390 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1316 [inline] __se_sys_sendfile64 fs/read_write.c:1308 [inline] __x64_sys_sendfile64+0x155/0x220 fs/read_write.c:1308 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x44fff9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 b4 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6af11ff0f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000044fff9 RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003 RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000004e2078 R13: 00007f6af11ff674 R14: 00000000004a242f R15: 000000000051bfa0 sched: RT throttling activated