Hello, syzbot found the following issue on: HEAD commit: 9e4c6c1ad9a1 Merge tag 'io_uring-6.12-20241011' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=121bf840580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7a3fccdd0bb995 dashboard link: https://syzkaller.appspot.com/bug?extid=c4cf28ed38d86d6b549d compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15f27b27980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=161bf840580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b800ca2864ac/disk-9e4c6c1a.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d73e5030d835/vmlinux-9e4c6c1a.xz kernel image: https://storage.googleapis.com/syzbot-assets/01db64f363e3/bzImage-9e4c6c1a.xz Bisection is inconclusive: the first bad commit could be any of: 781773e3b680 sched/fair: Implement ENQUEUE_DELAYED a1c446611e31 sched,freezer: Mark TASK_FROZEN special e1459a50ba31 sched: Teach dequeue_task() about special task states f12e148892ed sched/fair: Prepare pick_next_task() for delayed dequeue 152e11f6df29 sched/fair: Implement delayed dequeue 2e0199df252a sched/fair: Prepare exit/cleanup paths for delayed_dequeue 54a58a787791 sched/fair: Implement DELAY_ZERO bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13491087980000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c4cf28ed38d86d6b549d@xxxxxxxxxxxxxxxxxxxxxxxxx rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5242/1:b..l rcu: (detected by 0, t=10503 jiffies, g=7693, q=1717126 ncpus=2) task:udevd state:R running task stack:23632 pid:5242 tgid:5242 ppid:4675 flags:0x00000002 Call Trace: <TASK> context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1843/0x4ae0 kernel/sched/core.c:6682 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7004 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:arch_stack_walk+0x139/0x150 arch/x86/kernel/stacktrace.c:30 Code: 90 84 c0 74 11 48 89 df e8 34 9e 09 00 83 bd 70 ff ff ff 00 75 d0 65 48 8b 04 25 28 00 00 00 48 3b 45 d0 75 13 48 83 c4 68 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 44 4e 85 0a 0f 1f 40 RSP: 0018:ffffc9000377f650 EFLAGS: 00000286 RAX: 1d18e14b92e1d000 RBX: ffffc9000377f6d0 RCX: ffffffff9179c000 RDX: ffffffff91947d00 RSI: ffffffff8c0adc40 RDI: ffffffff8c602720 RBP: ffffc9000377f670 R08: ffffffff901bc6af R09: 1ffffffff20378d5 R10: dffffc0000000000 R11: fffffbfff20378d6 R12: ffff8880741c3c00 R13: ffffffff8180a090 R14: ffffc9000377f6c0 R15: 0000000000000000 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 save_stack+0xfb/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x430 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1108 [inline] free_unref_page+0xcd0/0xf00 mm/page_alloc.c:2638 discard_slab mm/slub.c:2677 [inline] __put_partials+0xeb/0x130 mm/slub.c:3145 put_cpu_partial+0x17c/0x250 mm/slub.c:3220 __slab_free+0x2ea/0x3d0 mm/slub.c:4449 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x23/0xb0 mm/kasan/common.c:385 kasan_kmalloc include/linux/kasan.h:257 [inline] __do_kmalloc_node mm/slub.c:4264 [inline] __kmalloc_node_noprof+0x22a/0x440 mm/slub.c:4270 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:658 seq_buf_alloc fs/seq_file.c:38 [inline] seq_read_iter+0x20c/0xd70 fs/seq_file.c:210 new_sync_read fs/read_write.c:488 [inline] vfs_read+0x9bb/0xbc0 fs/read_write.c:569 ksys_read+0x183/0x2b0 fs/read_write.c:712 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f550dd16b6a RSP: 002b:00007ffcb76d24a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00005632171f20f0 RCX: 00007f550dd16b6a RDX: 0000000000001000 RSI: 00005632172131c0 RDI: 0000000000000008 RBP: 00005632171f20f0 R08: 0000000000000008 R09: 0000000000080000 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000003fff R14: 00007ffcb76d2988 R15: 000000000000000a </TASK> rcu: rcu_preempt kthread starved for 10545 jiffies! g7693 f0x2 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:25816 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1843/0x4ae0 kernel/sched/core.c:6682 __schedule_loop kernel/sched/core.c:6759 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6774 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </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 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.12.0-rc2-syzkaller-00260-g9e4c6c1ad9a1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__sanitizer_cov_trace_cmp4+0x0/0x90 kernel/kcov.c:287 Code: 10 48 89 74 0a 18 4c 89 44 0a 20 c3 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 4c 8b 04 24 65 48 8b 14 25 80 d7 03 00 65 8b 05 b0 ee RSP: 0018:ffffc900001e7638 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000028000045 RCX: dffffc0000000000 RDX: ffff88801da88000 RSI: 0000000028000045 RDI: 0000000028000045 RBP: ffff888202716140 R08: ffffffff84eae69c R09: 1ffff11040346984 R10: dffffc0000000000 R11: ffffed1040346985 R12: 0000000000000014 R13: 0000000000000000 R14: ffff888202716154 R15: ffff888202716144 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdaa273ff8 CR3: 000000000e734000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <TASK> do_csum lib/checksum.c:77 [inline] ip_fast_csum+0x14a/0x2b0 lib/checksum.c:108 ip_rcv_core+0x415/0xd10 net/ipv4/ip_input.c:511 ip_rcv+0x4f/0x90 net/ipv4/ip_input.c:565 __netif_receive_skb_one_core net/core/dev.c:5666 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5779 process_backlog+0x662/0x15b0 net/core/dev.c:6111 __napi_poll+0xcb/0x490 net/core/dev.c:6775 napi_poll net/core/dev.c:6844 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6966 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:927 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
