================================ WARNING: inconsistent lock state 5.15.167-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. syz.2.282/5321 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff8880260309e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff8880260309e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2271 [inline] ffff8880260309e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x160/0x980 drivers/net/ppp/ppp_generic.c:2303 {IN-SOFTIRQ-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] __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 run_ksoftirqd+0xc6/0x120 kernel/softirq.c:925 smpboot_thread_fn+0x51b/0x9d0 kernel/smpboot.c:164 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 irq event stamp: 1659 hardirqs last enabled at (1659): [] __local_bh_enable_ip+0x164/0x1f0 kernel/softirq.c:388 hardirqs last disabled at (1657): [] __local_bh_enable_ip+0x102/0x1f0 kernel/softirq.c:365 softirqs last enabled at (1658): [] spin_unlock_bh include/linux/spinlock.h:408 [inline] softirqs last enabled at (1658): [] __release_sock+0x9c/0x4b0 net/core/sock.c:2717 softirqs last disabled at (1656): [] spin_lock_bh include/linux/spinlock.h:368 [inline] softirqs last disabled at (1656): [] release_sock+0x2c/0x1c0 net/core/sock.c:3263 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&pch->downl); lock(&pch->downl); *** DEADLOCK *** 2 locks held by syz.2.282/5321: #0: ffff888063558120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1676 [inline] #0: ffff888063558120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppoe_sendmsg+0x4d/0x740 drivers/net/ppp/pppoe.c:849 #1: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 0 PID: 5321 Comm: syz.2.282 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+0xc78/0x1ff0 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] __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 RIP: 0033:0x7fd7c23e5f39 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:00007fd7c081c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fd7c259e130 RCX: 00007fd7c23e5f39 RDX: 0400000000000026 RSI: 0000000020001cc0 RDI: 0000000000000006 RBP: 00007fd7c2458216 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd7c259e130 R15: 00007ffe2e4ab2f8