================================ WARNING: inconsistent lock state 5.15.167-syzkaller #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. ksoftirqd/1/20 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff0000d73231e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000d73231e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2271 [inline] ffff0000d73231e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x168/0x840 drivers/net/ppp/ppp_generic.c:2303 {SOFTIRQ-ON-W} state was registered at: lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c 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+0x168/0x840 drivers/net/ppp/ppp_generic.c:2303 pppoe_rcv_core+0xf8/0x330 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1059 [inline] __release_sock+0x1a8/0x408 net/core/sock.c:2724 release_sock+0x68/0x270 net/core/sock.c:3265 pppoe_sendmsg+0xc8/0x5d0 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x584/0x870 net/socket.c:2431 ___sys_sendmsg+0x214/0x294 net/socket.c:2485 __sys_sendmmsg+0x23c/0x648 net/socket.c:2571 __do_sys_sendmmsg net/socket.c:2600 [inline] __se_sys_sendmmsg net/socket.c:2597 [inline] __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2597 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 irq event stamp: 696418 hardirqs last enabled at (696418): [] __local_bh_enable_ip+0x230/0x470 kernel/softirq.c:388 hardirqs last disabled at (696417): [] __local_bh_enable_ip+0x1a0/0x470 kernel/softirq.c:365 softirqs last enabled at (696398): [] softirq_handle_end kernel/softirq.c:401 [inline] softirqs last enabled at (696398): [] handle_softirqs+0xb88/0xdbc kernel/softirq.c:586 softirqs last disabled at (696403): [] run_ksoftirqd+0x6c/0x29c kernel/softirq.c:925 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/1/20: #0: ffff800014c917e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #1: ffff0000daf730a0 (slock-AF_PPPOX){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #1: ffff0000daf730a0 (slock-AF_PPPOX){+.-.}-{2:2}, at: __sk_receive_skb+0x168/0x960 net/core/sock.c:521 #2: ffff0000daf73120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: sk_receive_skb include/net/sock.h:1933 [inline] #2: ffff0000daf73120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppoe_rcv+0x2c0/0x508 drivers/net/ppp/pppoe.c:451 #3: ffff800014c917e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 stack backtrace: CPU: 1 PID: 20 Comm: ksoftirqd/1 Not tainted 5.15.167-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_usage_bug+0x64c/0x9a8 kernel/locking/lockdep.c:3920 mark_lock_irq+0x980/0xd2c mark_lock+0x258/0x360 kernel/locking/lockdep.c:4591 __lock_acquire+0xb84/0x7638 kernel/locking/lockdep.c:4966 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c 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+0x168/0x840 drivers/net/ppp/ppp_generic.c:2303 pppoe_rcv_core+0xf8/0x330 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1059 [inline] __sk_receive_skb+0x3f0/0x960 net/core/sock.c:528 sk_receive_skb include/net/sock.h:1933 [inline] pppoe_rcv+0x2c0/0x508 drivers/net/ppp/pppoe.c:451 __netif_receive_skb_one_core net/core/dev.c:5485 [inline] __netif_receive_skb+0x18c/0x400 net/core/dev.c:5599 process_backlog+0x3ec/0x7e0 net/core/dev.c:6476 __napi_poll+0xb4/0x624 net/core/dev.c:7035 napi_poll net/core/dev.c:7102 [inline] net_rx_action+0x500/0xc10 net/core/dev.c:7192 handle_softirqs+0x384/0xdbc kernel/softirq.c:558 run_ksoftirqd+0x6c/0x29c kernel/softirq.c:925 smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870