================================ WARNING: inconsistent lock state 5.15.167-syzkaller #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. syz.4.44/3846 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff888142fc91e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff888142fc91e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2271 [inline] ffff888142fc91e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x160/0x980 drivers/net/ppp/ppp_generic.c:2303 {SOFTIRQ-ON-W} state was registered at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2271 [inline] ppp_input+0x160/0x980 drivers/net/ppp/ppp_generic.c:2303 pppoe_rcv_core+0x109/0x2f0 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1059 [inline] __release_sock+0x198/0x4b0 net/core/sock.c:2724 release_sock+0x5d/0x1c0 net/core/sock.c:3265 pppoe_sendmsg+0xd1/0x740 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485 __sys_sendmmsg+0x2bf/0x560 net/socket.c:2571 __do_sys_sendmmsg net/socket.c:2600 [inline] __se_sys_sendmmsg net/socket.c:2597 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2597 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 irq event stamp: 3288 hardirqs last enabled at (3288): [] __local_bh_enable_ip+0x164/0x1f0 kernel/softirq.c:388 hardirqs last disabled at (3287): [] __local_bh_enable_ip+0x102/0x1f0 kernel/softirq.c:365 softirqs last enabled at (2744): [] __do_softirq kernel/softirq.c:592 [inline] softirqs last enabled at (2744): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last enabled at (2744): [] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 softirqs last disabled at (3255): [] __do_softirq kernel/softirq.c:592 [inline] softirqs last disabled at (3255): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last disabled at (3255): [] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&pch->downl); lock(&pch->downl); *** DEADLOCK *** 4 locks held by syz.4.44/3846: #0: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312 #1: ffff88807eb8e0a0 (slock-AF_PPPOX){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #1: ffff88807eb8e0a0 (slock-AF_PPPOX){+.-.}-{2:2}, at: __sk_receive_skb+0x17c/0x9c0 net/core/sock.c:521 #2: ffff88807eb8e120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: __netif_receive_skb_one_core net/core/dev.c:5485 [inline] #2: ffff88807eb8e120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5599 #3: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 0 PID: 3846 Comm: syz.4.44 Not tainted 5.15.167-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 valid_state+0x134/0x1c0 kernel/locking/lockdep.c:3932 mark_lock_irq+0xa8/0xba0 kernel/locking/lockdep.c:4135 mark_lock+0x21a/0x340 kernel/locking/lockdep.c:4591 __lock_acquire+0xb9d/0x1ff0 kernel/locking/lockdep.c:4966 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2271 [inline] ppp_input+0x160/0x980 drivers/net/ppp/ppp_generic.c:2303 pppoe_rcv_core+0x109/0x2f0 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1059 [inline] __sk_receive_skb+0x416/0x9c0 net/core/sock.c:528 __netif_receive_skb_one_core net/core/dev.c:5485 [inline] __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5599 process_backlog+0x363/0x7f0 net/core/dev.c:6476 __napi_poll+0xc7/0x440 net/core/dev.c:7035 napi_poll net/core/dev.c:7102 [inline] net_rx_action+0x617/0xda0 net/core/dev.c:7192 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:finish_lock_switch+0x91/0x100 kernel/sched/core.c:4782 Code: 45 31 c9 68 97 9b 59 81 e8 9c 11 09 00 48 83 c4 08 4c 89 ff e8 50 db fe ff 66 90 4c 89 ff e8 d6 48 e4 08 e8 51 3f 2d 00 fb 5b <41> 5c 41 5d 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 87 RSP: 0018:ffffc900014ef698 EFLAGS: 00000286 RAX: d28feadd0fc7c200 RBX: ffff88802102d974 RCX: ffffffff96868f03 RDX: dffffc0000000000 RSI: ffffffff8a8b2b00 RDI: ffffffff8ad904c0 RBP: ffffc900014ef710 R08: ffffffff8186db50 R09: ffffed1017207461 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff1101720760b R14: ffff8880b903b058 R15: ffff8880b903a300 finish_task_switch+0x134/0x630 kernel/sched/core.c:4899 context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12cc/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x25b/0x480 kernel/futex/core.c:2863 futex_wait+0x2f8/0x740 kernel/futex/core.c:2964 do_futex+0x1414/0x1810 kernel/futex/core.c:3982 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x407/0x490 kernel/futex/core.c:4040 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fba85887f39 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff5465d618 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fff5465d740 RCX: 00007fba85887f39 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fba85a3ff8c RBP: 00007fba85a3ff8c R08: 0000000000000010 R09: 00007fff5465d90f R10: 00007fff5465d720 R11: 0000000000000246 R12: 00000000000126e5 R13: 00007fff5465d720 R14: 0000000000000032 R15: 00000000000126b3 ---------------- Code disassembly (best guess): 0: 45 31 c9 xor %r9d,%r9d 3: 68 97 9b 59 81 push $0xffffffff81599b97 8: e8 9c 11 09 00 call 0x911a9 d: 48 83 c4 08 add $0x8,%rsp 11: 4c 89 ff mov %r15,%rdi 14: e8 50 db fe ff call 0xfffedb69 19: 66 90 xchg %ax,%ax 1b: 4c 89 ff mov %r15,%rdi 1e: e8 d6 48 e4 08 call 0x8e448f9 23: e8 51 3f 2d 00 call 0x2d3f79 28: fb sti 29: 5b pop %rbx * 2a: 41 5c pop %r12 <-- trapping instruction 2c: 41 5d pop %r13 2e: 41 5e pop %r14 30: 41 5f pop %r15 32: c3 ret 33: 44 89 f1 mov %r14d,%ecx 36: 80 e1 07 and $0x7,%cl 39: 80 c1 03 add $0x3,%cl 3c: 38 c1 cmp %al,%cl 3e: 7c 87 jl 0xffffffc7