syzbot has found a reproducer for the following issue on: HEAD commit: b311c1b497e5 Merge tag '6.11-rc4-server-fixes' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12dccc7b980000 kernel config: https://syzkaller.appspot.com/x/.config?x=df2f0ed7e30a639d dashboard link: https://syzkaller.appspot.com/bug?extid=d43eb079c2addf2439c3 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17cf93d5980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=101bb693980000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-b311c1b4.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/1c99fa48192f/vmlinux-b311c1b4.xz kernel image: https://storage.googleapis.com/syzbot-assets/16d5710a012a/bzImage-b311c1b4.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d43eb079c2addf2439c3@xxxxxxxxxxxxxxxxxxxxxxxxx ================================ WARNING: inconsistent lock state 6.11.0-rc4-syzkaller-00019-gb311c1b497e5 #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. ksoftirqd/0/16 [HC0[0]:SC1[1]:HE1:SE0] takes: ffff888039c531e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888039c531e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline] ffff888039c531e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x18b/0xa10 drivers/net/ppp/ppp_generic.c:2304 {SOFTIRQ-ON-W} state was registered at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __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+0x18b/0xa10 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x117/0x310 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1111 [inline] __release_sock+0x243/0x350 net/core/sock.c:3004 release_sock+0x61/0x1f0 net/core/sock.c:3558 pppoe_sendmsg+0xd5/0x750 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597 ___sys_sendmsg net/socket.c:2651 [inline] __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737 __do_sys_sendmmsg net/socket.c:2766 [inline] __se_sys_sendmmsg net/socket.c:2763 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f irq event stamp: 1309336 hardirqs last enabled at (1309336): [<ffffffff8bc0d5ff>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] hardirqs last enabled at (1309336): [<ffffffff8bc0d5ff>] _raw_spin_unlock_irqrestore+0x8f/0x140 kernel/locking/spinlock.c:194 hardirqs last disabled at (1309335): [<ffffffff8bc0d300>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (1309335): [<ffffffff8bc0d300>] _raw_spin_lock_irqsave+0xb0/0x120 kernel/locking/spinlock.c:162 softirqs last enabled at (1309326): [<ffffffff81578ffa>] run_ksoftirqd+0xca/0x130 kernel/softirq.c:928 softirqs last disabled at (1309331): [<ffffffff81578ffa>] run_ksoftirqd+0xca/0x130 kernel/softirq.c:928 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&pch->downl); <Interrupt> lock(&pch->downl); *** DEADLOCK *** 1 lock held by ksoftirqd/0/16: #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2267 [inline] #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ppp_input+0x55/0xa10 drivers/net/ppp/ppp_generic.c:2304 stack backtrace: CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.11.0-rc4-syzkaller-00019-gb311c1b497e5 #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: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 valid_state+0x13a/0x1c0 kernel/locking/lockdep.c:4012 mark_lock_irq+0xbb/0xc20 kernel/locking/lockdep.c:4215 mark_lock+0x223/0x350 kernel/locking/lockdep.c:4677 __lock_acquire+0xbf9/0x2040 kernel/locking/lockdep.c:5096 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __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+0x18b/0xa10 drivers/net/ppp/ppp_generic.c:2304 ppp_sync_process+0x71/0x160 drivers/net/ppp/ppp_synctty.c:490 tasklet_action_common+0x321/0x4d0 kernel/softirq.c:785 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
