================================ WARNING: inconsistent lock state 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. syz.1.559/6753 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff88807edec1e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88807edec1e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline] ffff88807edec1e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x104/0xbb0 drivers/net/ppp/ppp_generic.c:2304 {SOFTIRQ-ON-W} state was registered at: lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/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+0x104/0xbb0 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x22c/0x320 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1113 [inline] __release_sock+0x35f/0x400 net/core/sock.c:3072 release_sock+0x5a/0x220 net/core/sock.c:3626 pppoe_sendmsg+0x625/0x7c0 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg net/socket.c:744 [inline] ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2602 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2656 __sys_sendmmsg+0x2a5/0x450 net/socket.c:2735 __compat_sys_sendmmsg net/compat.c:360 [inline] __do_compat_sys_sendmmsg net/compat.c:367 [inline] __se_compat_sys_sendmmsg net/compat.c:364 [inline] __ia32_compat_sys_sendmmsg+0x9d/0x100 net/compat.c:364 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e irq event stamp: 5920 hardirqs last enabled at (5920): [] __local_bh_enable_ip+0xa4/0x120 kernel/softirq.c:387 hardirqs last disabled at (5919): [] __local_bh_enable_ip+0xcd/0x120 kernel/softirq.c:364 softirqs last enabled at (5874): [] pppoe_sendmsg+0x625/0x7c0 drivers/net/ppp/pppoe.c:903 softirqs last disabled at (5885): [] __do_softirq kernel/softirq.c:588 [inline] softirqs last disabled at (5885): [] invoke_softirq kernel/softirq.c:428 [inline] softirqs last disabled at (5885): [] __irq_exit_rcu kernel/softirq.c:637 [inline] softirqs last disabled at (5885): [] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 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.1.559/6753: #0: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: local_lock_release include/linux/local_lock_internal.h:38 [inline] #0: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x3f1/0x15f0 net/core/dev.c:6105 #1: ffff88801211f1d8 (slock-AF_PPPOX){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #1: ffff88801211f1d8 (slock-AF_PPPOX){+.-.}-{2:2}, at: __sk_receive_skb+0x1dd/0x890 net/core/sock.c:563 #2: ffff88801211f258 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: sk_receive_skb include/net/sock.h:1898 [inline] #2: ffff88801211f258 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppoe_rcv+0x7b2/0xa70 drivers/net/ppp/pppoe.c:451 #3: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #3: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #3: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2267 [inline] #3: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: ppp_input+0x70/0xbb0 drivers/net/ppp/ppp_generic.c:2304 stack backtrace: CPU: 0 UID: 0 PID: 6753 Comm: syz.1.559 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_usage_bug.part.0+0x3a2/0x560 kernel/locking/lockdep.c:4038 print_usage_bug kernel/locking/lockdep.c:4006 [inline] valid_state kernel/locking/lockdep.c:4052 [inline] mark_lock_irq kernel/locking/lockdep.c:4263 [inline] mark_lock+0x92d/0xc60 kernel/locking/lockdep.c:4725 mark_usage kernel/locking/lockdep.c:4614 [inline] __lock_acquire+0x11e1/0x3ce0 kernel/locking/lockdep.c:5156 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/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+0x104/0xbb0 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x22c/0x320 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1113 [inline] __sk_receive_skb+0x7aa/0x890 net/core/sock.c:570 sk_receive_skb include/net/sock.h:1898 [inline] pppoe_rcv+0x7b2/0xa70 drivers/net/ppp/pppoe.c:451 __netif_receive_skb_one_core+0x1b1/0x1e0 net/core/dev.c:5662 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5775 process_backlog+0x443/0x15f0 net/core/dev.c:6107 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0xa92/0x1010 net/core/dev.c:6962 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline] sysvec_apic_timer_interrupt+0x57/0xc0 arch/x86/kernel/apic/apic.c:1037 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0023:0xf742e579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f571661c EFLAGS: 00000246 RAX: 0000000000000001 RBX: 00000000f7454f8c RCX: 00000000f742e579 RDX: 00000000000f4240 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 vkms_vblank_simulate: vblank timer overrun ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi