================================ WARNING: inconsistent lock state 6.1.112-syzkaller #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. ksoftirqd/1/21 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff888074af41e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888074af41e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline] ffff888074af41e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x185/0xa00 drivers/net/ppp/ppp_generic.c:2304 {SOFTIRQ-ON-W} state was registered at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline] ppp_input+0x185/0xa00 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x112/0x300 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1117 [inline] __release_sock+0x198/0x4b0 net/core/sock.c:2936 release_sock+0x5d/0x1c0 net/core/sock.c:3500 pppoe_sendmsg+0xd1/0x740 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514 ___sys_sendmsg net/socket.c:2568 [inline] __sys_sendmmsg+0x3ab/0x730 net/socket.c:2654 __do_sys_sendmmsg net/socket.c:2683 [inline] __se_sys_sendmmsg net/socket.c:2680 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2680 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 irq event stamp: 1161644 hardirqs last enabled at (1161644): [] __local_bh_enable_ip+0x164/0x1f0 kernel/softirq.c:401 hardirqs last disabled at (1161643): [] __local_bh_enable_ip+0x102/0x1f0 kernel/softirq.c:378 softirqs last enabled at (1161618): [] run_ksoftirqd+0xc6/0x120 kernel/softirq.c:938 softirqs last disabled at (1161623): [] run_ksoftirqd+0xc6/0x120 kernel/softirq.c:938 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&pch->downl); lock(&pch->downl); *** DEADLOCK *** 4 locks held by ksoftirqd/1/21: #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x2c9/0x760 net/core/dev.c:5969 #1: ffff8881432f30b0 (slock-AF_PPPOX){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #1: ffff8881432f30b0 (slock-AF_PPPOX){+.-.}-{2:2}, at: __sk_receive_skb+0x188/0x9d0 net/core/sock.c:562 #2: ffff8881432f3130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: __netif_receive_skb_one_core net/core/dev.c:5528 [inline] #2: ffff8881432f3130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5642 #3: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2267 [inline] #3: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: ppp_input+0x51/0xa00 drivers/net/ppp/ppp_generic.c:2304 stack backtrace: CPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 6.1.112-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+0x1e3/0x2cb lib/dump_stack.c:106 valid_state+0x136/0x1c0 kernel/locking/lockdep.c:3969 mark_lock_irq+0xa8/0xba0 kernel/locking/lockdep.c:4172 mark_lock+0x21c/0x340 kernel/locking/lockdep.c:4628 __lock_acquire+0xb7f/0x1f80 kernel/locking/lockdep.c:5003 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline] ppp_input+0x185/0xa00 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x112/0x300 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1117 [inline] __sk_receive_skb+0x41a/0x9d0 net/core/sock.c:569 __netif_receive_skb_one_core net/core/dev.c:5528 [inline] __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5642 process_backlog+0x381/0x760 net/core/dev.c:5970 __napi_poll+0xc7/0x470 net/core/dev.c:6537 napi_poll net/core/dev.c:6604 [inline] net_rx_action+0x70f/0xeb0 net/core/dev.c:6718 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 run_ksoftirqd+0xc6/0x120 kernel/softirq.c:938 smpboot_thread_fn+0x52c/0xa30 kernel/smpboot.c:164 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295