syzbot has found a reproducer for the following issue on:
HEAD commit: 55be6084c8e0 Merge tag 'timers-core-2022-10-05' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1623ec72880000 kernel config: https://syzkaller.appspot.com/x/.config?x=df75278aabf0681a dashboard link: https://syzkaller.appspot.com/bug?extid=69904c3b4a09e8fa2e1b compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e2e478880000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=149ca17c880000
Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/9d967e5d91fa/disk-55be6084.raw.... vmlinux: https://storage.googleapis.com/syzbot-assets/9a8cffcbc089/vmlinux-55be6084.x...
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+69904c3b4a09e8fa2e1b@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=d61c/1/0x4000000000000000 softirq=5548/5551 fqs=5 (t=10501 jiffies g=4985 q=1169 ncpus=2) rcu: rcu_preempt kthread starved for 10488 jiffies! g4985 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:28728 pid:17 ppid:2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5178 [inline] __schedule+0xadf/0x5270 kernel/sched/core.c:6490 schedule+0xda/0x1b0 kernel/sched/core.c:6566 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1935 rcu_gp_fqs_loop+0x190/0x910 kernel/rcu/tree.c:1658 rcu_gp_kthread+0x236/0x360 kernel/rcu/tree.c:1857 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 47 Comm: kworker/u4:3 Not tainted 6.0.0-syzkaller-09589-g55be6084c8e0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x7/0x60 kernel/kcov.c:200 Code: 4c 00 5d be 03 00 00 00 e9 d6 43 84 02 66 0f 1f 44 00 00 48 8b be a8 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 8b 05 f9 24 87 7e <89> c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 80 6f 02 00 a9 RSP: 0018:ffffc900001f0c48 EFLAGS: 00000286 RAX: 0000000000000101 RBX: ffff88806b299c90 RCX: ffffffff878c4a1d RDX: ffff888017893b00 RSI: 0000000000000100 RDI: 0000000000000007 RBP: fffffff0a3da8872 R08: 0000000000000007 R09: 0000000000000000 R10: fffffff0a3da8872 R11: 000000000008c07d R12: fffffff0a3da8872 R13: ffff888018f5ab00 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000026ef0000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> pie_calculate_probability+0x32b/0x7c0 net/sched/sch_pie.c:387 fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:380 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:382 [inline] RIP: 0010:__rcu_read_unlock+0x2d/0x570 kernel/rcu/tree_plugin.h:421 Code: 55 41 54 55 65 48 8b 2c 25 80 6f 02 00 53 48 8d bd 3c 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 24 02 00 00 65 RSP: 0018:ffffc90000b87c58 EFLAGS: 00000a07 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff891cd30e RDI: ffff888017893f3c RBP: ffff888017893b00 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000345 rcu_read_unlock include/linux/rcupdate.h:770 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x853/0xfa0 net/batman-adv/network-coding.c:719 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.452 msecs CPU: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.0.0-syzkaller-09589-g55be6084c8e0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 RIP: 0010:pie_calculate_probability+0x1a5/0x7c0 net/sched/sch_pie.c:354 Code: 20 48 b8 82 be e0 12 01 00 00 00 48 89 fa 48 c1 ea 03 4c 0f af e0 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 85 e4 05 00 00 <4c> 89 ea 4c 8b 7b 20 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 RSP: 0018:ffffc90000157b40 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff88806b81acc0 RCX: 0000000000000100 RDX: 1ffff1100d70359c RSI: ffffffff878c480f RDI: ffff88806b81ace0 RBP: 0000000225c17d04 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000008c07d R12: 00000015798ee228 R13: ffff888017498300 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffddaac90a8 CR3: 0000000011aec000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:380 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 run_ksoftirqd kernel/softirq.c:934 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:926 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK>