On Fri, Dec 15, 2023 at 4:15 AM Eric Dumazet <edumazet@xxxxxxxxxx> wrote: > > On Mon, Dec 4, 2023 at 10:45 AM syzbot > <syzbot+45b67ef6e09a39a2cbcd@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 753c8608f3e5 Merge tag 'for-netdev' of https://git.kernel... > > git tree: net-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=1381f352e80000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=f8715b6ede5c4b90 > > dashboard link: https://syzkaller.appspot.com/bug?extid=45b67ef6e09a39a2cbcd > > compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15abc0e2e80000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10b0c7c2e80000 > > > > Downloadable assets: > > disk image: https://storage.googleapis.com/syzbot-assets/17dd61ceadb9/disk-753c8608.raw.xz > > vmlinux: https://storage.googleapis.com/syzbot-assets/fed6ba43d9bd/vmlinux-753c8608.xz > > kernel image: https://storage.googleapis.com/syzbot-assets/3e68e49966d3/bzImage-753c8608.xz > > > > The issue was bisected to: > > > > commit b5b73b26b3ca34574124ed7ae9c5ba8391a7f176 > > Author: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx> > > Date: Thu Sep 10 00:03:11 2020 +0000 > > > > taprio: Fix allowing too small intervals > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13b90672e80000 > > final oops: https://syzkaller.appspot.com/x/report.txt?x=10790672e80000 > > console output: https://syzkaller.appspot.com/x/log.txt?x=17b90672e80000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+45b67ef6e09a39a2cbcd@xxxxxxxxxxxxxxxxxxxxxxxxx > > Fixes: b5b73b26b3ca ("taprio: Fix allowing too small intervals") > > > > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: > > rcu: 0-...!: (2 GPs behind) idle=9444/0/0x3 softirq=6168/6168 fqs=0 > > rcu: (detected by 1, t=10504 jiffies, g=7341, q=186 ncpus=2) > > Sending NMI from CPU 1 to CPUs 0: > > NMI backtrace for cpu 0 > > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.7.0-rc3-syzkaller-00666-g753c8608f3e5 #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 > > RIP: 0010:rcu_is_watching+0x7c/0xb0 kernel/rcu/tree.c:701 > > Code: 89 da 48 c1 ea 03 0f b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1c 8b 03 c1 e8 02 83 e0 01 65 ff 0d fc d9 93 7e <74> 03 5b 5d c3 e8 fa 9d 90 ff 5b 5d c3 48 89 df e8 bf 90 6e 00 eb > > RSP: 0000:ffffc90000006b90 EFLAGS: 00000006 > > RAX: 0000000000000001 RBX: ffff8880b9836de8 RCX: ffffffff81680cf5 > > RDX: 0000000000000000 RSI: ffffffff8b2f1340 RDI: ffffffff8ca6ea60 > > RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff1e31dea > > R10: ffffffff8f18ef57 R11: 0000000000000004 R12: ffff8880b982b958 > > R13: 179cc057f149e962 R14: ffff88807627b340 R15: ffffffff88a26e60 > > FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f3bc135f410 CR3: 000000001ab22000 CR4: 00000000003506f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > <NMI> > > </NMI> > > <IRQ> > > trace_lock_release include/trace/events/lock.h:69 [inline] > > lock_release+0x4bf/0x690 kernel/locking/lockdep.c:5765 > > __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] > > _raw_spin_unlock_irqrestore+0x1a/0x70 kernel/locking/spinlock.c:194 > > __run_hrtimer kernel/time/hrtimer.c:1684 [inline] > > __hrtimer_run_queues+0x58b/0xc20 kernel/time/hrtimer.c:1752 > > hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814 > > local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline] > > __sysvec_apic_timer_interrupt+0x105/0x400 arch/x86/kernel/apic/apic.c:1082 > > sysvec_apic_timer_interrupt+0x43/0xb0 arch/x86/kernel/apic/apic.c:1076 > > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 > > RIP: 0010:unwind_get_return_address+0xa1/0xe0 arch/x86/kernel/unwind_orc.c:369 > > Code: 00 31 ff 89 c5 89 c6 e8 8d 9d 4d 00 85 ed 74 b9 e8 14 a2 4d 00 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <75> 28 48 8b 5b 48 e8 f4 a1 4d 00 48 89 d8 5b 5d 41 5c c3 48 89 df > > RSP: 0000:ffffc90000006f08 EFLAGS: 00000246 > > RAX: dffffc0000000000 RBX: ffffc90000006f30 RCX: ffffffff8139f033 > > RDX: 1ffff92000000def RSI: ffffffff8139f03c RDI: 0000000000000005 > > RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 > > R10: 0000000000000001 R11: 0000000000000003 R12: ffffc90000006f78 > > R13: ffffffff8174f4a0 R14: ffffc90000006ff0 R15: ffffffff8cc95900 > > arch_stack_walk+0xbe/0x170 arch/x86/kernel/stacktrace.c:26 > > stack_trace_save+0x96/0xd0 kernel/stacktrace.c:122 > > kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 > > kasan_set_track+0x25/0x30 mm/kasan/common.c:52 > > kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522 > > ____kasan_slab_free mm/kasan/common.c:236 [inline] > > ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200 > > kasan_slab_free include/linux/kasan.h:164 [inline] > > slab_free_hook mm/slub.c:1800 [inline] > > slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826 > > slab_free mm/slub.c:3809 [inline] > > kmem_cache_free+0xf8/0x350 mm/slub.c:3831 > > kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:1015 > > tcp_rcv_established+0xd5f/0x20e0 net/ipv4/tcp_input.c:6065 > > tcp_v4_do_rcv+0x68c/0xa10 net/ipv4/tcp_ipv4.c:1912 > > tcp_v4_rcv+0x3892/0x3b40 net/ipv4/tcp_ipv4.c:2335 > > ip_protocol_deliver_rcu+0x9f/0x480 net/ipv4/ip_input.c:205 > > ip_local_deliver_finish+0x2e4/0x510 net/ipv4/ip_input.c:233 > > NF_HOOK include/linux/netfilter.h:314 [inline] > > NF_HOOK include/linux/netfilter.h:308 [inline] > > ip_local_deliver+0x18e/0x1f0 net/ipv4/ip_input.c:254 > > dst_input include/net/dst.h:461 [inline] > > ip_sublist_rcv_finish+0x99/0x2e0 net/ipv4/ip_input.c:580 > > ip_list_rcv_finish.constprop.0+0x560/0x720 net/ipv4/ip_input.c:631 > > ip_sublist_rcv net/ipv4/ip_input.c:639 [inline] > > ip_list_rcv+0x339/0x440 net/ipv4/ip_input.c:674 > > __netif_receive_skb_list_ptype net/core/dev.c:5572 [inline] > > __netif_receive_skb_list_core+0x52c/0x8a0 net/core/dev.c:5620 > > __netif_receive_skb_list net/core/dev.c:5672 [inline] > > netif_receive_skb_list_internal+0x769/0xe00 net/core/dev.c:5763 > > gro_normal_list include/net/gro.h:439 [inline] > > gro_normal_list include/net/gro.h:435 [inline] > > napi_complete_done+0x23f/0x990 net/core/dev.c:6103 > > virtqueue_napi_complete drivers/net/virtio_net.c:440 [inline] > > virtnet_poll+0xf4a/0x15d0 drivers/net/virtio_net.c:2158 > > __napi_poll.constprop.0+0xb4/0x540 net/core/dev.c:6533 > > napi_poll net/core/dev.c:6602 [inline] > > net_rx_action+0x956/0xe90 net/core/dev.c:6735 > > __do_softirq+0x21a/0x8de kernel/softirq.c:553 > > invoke_softirq kernel/softirq.c:427 [inline] > > __irq_exit_rcu kernel/softirq.c:632 [inline] > > irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644 > > common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:247 > > </IRQ> > > <TASK> > > asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636 > > RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] > > RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline] > > RIP: 0010:acpi_safe_halt+0x1b/0x20 drivers/acpi/processor_idle.c:113 > > Code: ed c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 65 48 8b 04 25 c0 bc 03 00 48 8b 00 a8 08 75 0c 66 90 0f 00 2d b7 7b ba 00 fb f4 <fa> c3 0f 1f 00 0f b6 47 08 3c 01 74 0b 3c 02 74 05 8b 7f 04 eb 9f > > RSP: 0000:ffffffff8cc07d68 EFLAGS: 00000246 > > RAX: 0000000000004000 RBX: 0000000000000001 RCX: ffffffff8a7fa837 > > RDX: 0000000000000001 RSI: ffff888014ebd800 RDI: ffff888014ebd864 > > RBP: ffff888014ebd864 R08: 0000000000000001 R09: ffffed1017306dbd > > R10: ffff8880b9836deb R11: 0000000000000000 R12: ffff8881412c4000 > > R13: ffffffff8db1cf20 R14: 0000000000000000 R15: 0000000000000000 > > acpi_idle_enter+0xc5/0x160 drivers/acpi/processor_idle.c:707 > > cpuidle_enter_state+0x83/0x500 drivers/cpuidle/cpuidle.c:267 > > cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:388 > > cpuidle_idle_call kernel/sched/idle.c:215 [inline] > > do_idle+0x319/0x400 kernel/sched/idle.c:282 > > cpu_startup_entry+0x50/0x60 kernel/sched/idle.c:380 > > rest_init+0x16f/0x2b0 init/main.c:730 > > arch_call_rest_init+0x13/0x30 init/main.c:827 > > start_kernel+0x39f/0x480 init/main.c:1072 > > x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:555 > > x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:536 > > secondary_startup_64_no_verify+0x166/0x16b > > </TASK> > > INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 5.004 msecs > > rcu: rcu_preempt kthread starved for 10504 jiffies! g7341 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:28752 pid:17 tgid:17 ppid:2 flags:0x00004000 > > Call Trace: > > <TASK> > > context_switch kernel/sched/core.c:5376 [inline] > > __schedule+0xedb/0x5af0 kernel/sched/core.c:6688 > > __schedule_loop kernel/sched/core.c:6763 [inline] > > schedule+0xe9/0x270 kernel/sched/core.c:6778 > > schedule_timeout+0x137/0x290 kernel/time/timer.c:2167 > > rcu_gp_fqs_loop+0x1ec/0xb10 kernel/rcu/tree.c:1631 > > rcu_gp_kthread+0x24b/0x380 kernel/rcu/tree.c:1830 > > kthread+0x2c6/0x3a0 kernel/kthread.c:388 > > ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 > > ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 > > </TASK> > > rcu: Stack dump where RCU GP kthread last ran: > > CPU: 1 PID: 5093 Comm: syz-executor163 Not tainted 6.7.0-rc3-syzkaller-00666-g753c8608f3e5 #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 > > RIP: 0010:kvm_wait+0x146/0x180 arch/x86/kernel/kvm.c:1062 > > Code: 5b 5d 41 5c 41 5d e9 c9 34 4e 00 e8 c4 34 4e 00 e8 8f ed 54 00 66 90 e8 b8 34 4e 00 0f 00 2d 41 5a 90 09 e8 ac 34 4e 00 fb f4 <5b> 5d 41 5c 41 5d e9 9f 34 4e 00 e8 9a 34 4e 00 e8 d5 ed 54 00 e9 > > RSP: 0018:ffffc900001f0ae0 EFLAGS: 00000246 > > RAX: 0000000000000000 RBX: 0000000000000003 RCX: 1ffffffff23ec48c > > RDX: ffff888076299dc0 RSI: ffffffff81395da4 RDI: ffffffff8b2f13c0 > > RBP: ffff88807e768098 R08: 0000000000000001 R09: fffffbfff23e29e7 > > R10: ffffffff91f14f3f R11: 0000000000000002 R12: 0000000000000003 > > R13: 0000000000000003 R14: 0000000000000000 R15: ffffed100fced013 > > FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f3bc14032d0 CR3: 000000007af32000 CR4: 00000000003506f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > <IRQ> > > pv_wait arch/x86/include/asm/paravirt.h:598 [inline] > > pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] > > __pv_queued_spin_lock_slowpath+0x959/0xc70 kernel/locking/qspinlock.c:511 > > pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [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+0x20e/0x2b0 kernel/locking/spinlock_debug.c:115 > > spin_lock include/linux/spinlock.h:351 [inline] > > tcp_write_timer+0x2a/0x2b0 net/ipv4/tcp_timer.c:708 > > call_timer_fn+0x193/0x590 kernel/time/timer.c:1700 > > expire_timers kernel/time/timer.c:1751 [inline] > > __run_timers+0x764/0xb20 kernel/time/timer.c:2022 > > run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035 > > __do_softirq+0x21a/0x8de kernel/softirq.c:553 > > invoke_softirq kernel/softirq.c:427 [inline] > > __irq_exit_rcu kernel/softirq.c:632 [inline] > > irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644 > > sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 > > </IRQ> > > <TASK> > > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 > > RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline] > > RIP: 0010:smp_call_function_many_cond+0x4e4/0x1550 kernel/smp.c:855 > > Code: 0b 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 8e c0 0b 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 24 0e 00 00 8b 43 08 31 > > RSP: 0018:ffffc90003bffa48 EFLAGS: 00000293 > > RAX: 0000000000000000 RBX: ffff8880b98441a0 RCX: ffffffff817bd1e8 > > RDX: ffff888076299dc0 RSI: ffffffff817bd1c2 RDI: 0000000000000005 > > RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 > > R10: 0000000000000001 R11: 0000000000000001 R12: ffffed1017308835 > > R13: 0000000000000001 R14: ffff8880b98441a8 R15: ffff8880b993d8c0 > > on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1023 > > __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline] > > flush_tlb_multi arch/x86/mm/tlb.c:944 [inline] > > flush_tlb_mm_range+0x28f/0x320 arch/x86/mm/tlb.c:1030 > > tlb_flush arch/x86/include/asm/tlb.h:20 [inline] > > tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:458 [inline] > > tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:448 [inline] > > tlb_flush_mmu mm/mmu_gather.c:299 [inline] > > tlb_finish_mmu+0x335/0x6f0 mm/mmu_gather.c:392 > > exit_mmap+0x38b/0xa70 mm/mmap.c:3321 > > __mmput+0x12a/0x4d0 kernel/fork.c:1349 > > mmput+0x62/0x70 kernel/fork.c:1371 > > exit_mm kernel/exit.c:567 [inline] > > do_exit+0x9ad/0x2ae0 kernel/exit.c:858 > > do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 > > __do_sys_exit_group kernel/exit.c:1032 [inline] > > __se_sys_exit_group kernel/exit.c:1030 [inline] > > __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030 > > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 > > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > RIP: 0033:0x7f3bc13802e9 > > Code: Unable to access opcode bytes at 0x7f3bc13802bf. > > RSP: 002b:00007ffde3662848 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 > > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3bc13802e9 > > RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 > > RBP: 00007f3bc1400390 R08: ffffffffffffffb8 R09: 0000000100000000 > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3bc1400390 > > R13: 0000000000000000 R14: 00007f3bc1402ec0 R15: 00007f3bc13507c0 > > </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 > Vinicius, This one has a reproducer. Can you please take a look - and note what Eric is saying here. In some cases for example the code is invoking from the timer while not holding the qdisc spinlock. cheers, jamal > FYI : Many other syzbot reports are pointing to taprio these days. > > In a3d43c0d56f1b94e74963a2fbadfb70126d92213 ("taprio: Add support > adding an admin schedule"), > advance_sched() was changed to call switch_schedules(q, &admin, &oper); > > This is done while qdisc spinlock is not held, I fail to see how this > can work safely ? > > Which lock is supposed to protect q->oper_sched and q->admin_sched ? > > This can not be q->current_entry_lock in some cases, and qdisc lock in others.
