===================================================== WARNING: SOFTIRQ-READ-safe -> SOFTIRQ-READ-unsafe lock order detected 5.15.167-syzkaller #0 Not tainted ----------------------------------------------------- syz.4.95/4263 [HC0[0]:SC0[8]:HE1:SE0] is trying to acquire: ffff888074d919e0 (&pch->downl){+.+.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] ffff888074d919e0 (&pch->downl){+.+.}-{2:2}, at: ppp_connect_channel+0x190/0x640 drivers/net/ppp/ppp_generic.c:3484 and this task is already holding: ffff88807b2f2dd0 (&ppp->rlock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] ffff88807b2f2dd0 (&ppp->rlock){+...}-{2:2}, at: ppp_connect_channel+0x181/0x640 drivers/net/ppp/ppp_generic.c:3483 which would create a new lock dependency: (&ppp->rlock){+...}-{2:2} -> (&pch->downl){+.+.}-{2:2} but this new dependency connects a SOFTIRQ-READ-irq-safe lock: (&pch->upl){++.-}-{2:2} ... which became SOFTIRQ-READ-irq-safe at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline] _raw_read_lock_bh+0x39/0x50 kernel/locking/spinlock.c:252 ppp_input+0x361/0x980 drivers/net/ppp/ppp_generic.c:2306 ppp_async_process+0x7b/0x140 drivers/net/ppp/ppp_async.c:505 tasklet_action_common+0x3cb/0x4a0 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 to a SOFTIRQ-READ-irq-unsafe lock: (&pch->downl){+.+.}-{2:2} ... which became SOFTIRQ-READ-irq-unsafe 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] __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 other info that might help us debug this: Chain exists of: &pch->upl --> &ppp->rlock --> &pch->downl Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pch->downl); local_irq_disable(); lock(&pch->upl); lock(&ppp->rlock); lock(&pch->upl); *** DEADLOCK *** 5 locks held by syz.4.95/4263: #0: ffffffff8d2c7a48 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x10e/0x1cd0 drivers/net/ppp/ppp_generic.c:726 #1: ffff888065b760c0 (&pn->all_ppp_mutex){+.+.}-{3:3}, at: ppp_connect_channel+0x5e/0x640 drivers/net/ppp/ppp_generic.c:3473 #2: ffff888074d91a40 (&pch->upl){++.-}-{2:2}, at: ppp_connect_channel+0x87/0x640 drivers/net/ppp/ppp_generic.c:3477 #3: ffff88807b2f2e10 (&ppp->wlock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] #3: ffff88807b2f2e10 (&ppp->wlock){+...}-{2:2}, at: ppp_connect_channel+0x170/0x640 drivers/net/ppp/ppp_generic.c:3483 #4: ffff88807b2f2dd0 (&ppp->rlock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] #4: ffff88807b2f2dd0 (&ppp->rlock){+...}-{2:2}, at: ppp_connect_channel+0x181/0x640 drivers/net/ppp/ppp_generic.c:3483 the dependencies between SOFTIRQ-READ-irq-safe lock and the holding lock: -> (&pch->upl){++.-}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:324 ppp_disconnect_channel+0x2f/0x2d0 drivers/net/ppp/ppp_generic.c:3521 ppp_unregister_channel+0xb5/0x2f0 drivers/net/ppp/ppp_generic.c:2995 ppp_asynctty_close+0xed/0x170 drivers/net/ppp/ppp_async.c:237 tty_ldisc_kill+0xa6/0x1a0 drivers/tty/tty_ldisc.c:629 tty_ldisc_release+0x19d/0x200 drivers/tty/tty_ldisc.c:803 tty_release_struct+0x27/0xd0 drivers/tty/tty_io.c:1708 tty_release+0xd53/0x1310 drivers/tty/tty_io.c:1880 __fput+0x3fe/0x8e0 fs/file_table.c:280 task_work_run+0x129/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x6a3/0x2480 kernel/exit.c:874 do_group_exit+0x144/0x310 kernel/exit.c:996 get_signal+0xc66/0x14e0 kernel/signal.c:2897 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 HARDIRQ-ON-R at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline] _raw_read_lock_bh+0x39/0x50 kernel/locking/spinlock.c:252 ppp_channel_push+0x2c/0x220 drivers/net/ppp/ppp_generic.c:2185 ppp_write+0x291/0x390 drivers/net/ppp/ppp_generic.c:537 vfs_write+0x30c/0xe50 fs/read_write.c:592 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 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 IN-SOFTIRQ-R at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline] _raw_read_lock_bh+0x39/0x50 kernel/locking/spinlock.c:252 ppp_input+0x361/0x980 drivers/net/ppp/ppp_generic.c:2306 ppp_async_process+0x7b/0x140 drivers/net/ppp/ppp_async.c:505 tasklet_action_common+0x3cb/0x4a0 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 INITIAL USE at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:324 ppp_disconnect_channel+0x2f/0x2d0 drivers/net/ppp/ppp_generic.c:3521 ppp_unregister_channel+0xb5/0x2f0 drivers/net/ppp/ppp_generic.c:2995 ppp_asynctty_close+0xed/0x170 drivers/net/ppp/ppp_async.c:237 tty_ldisc_kill+0xa6/0x1a0 drivers/tty/tty_ldisc.c:629 tty_ldisc_release+0x19d/0x200 drivers/tty/tty_ldisc.c:803 tty_release_struct+0x27/0xd0 drivers/tty/tty_io.c:1708 tty_release+0xd53/0x1310 drivers/tty/tty_io.c:1880 __fput+0x3fe/0x8e0 fs/file_table.c:280 task_work_run+0x129/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x6a3/0x2480 kernel/exit.c:874 do_group_exit+0x144/0x310 kernel/exit.c:996 get_signal+0xc66/0x14e0 kernel/signal.c:2897 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 INITIAL READ USE at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline] _raw_read_lock_bh+0x39/0x50 kernel/locking/spinlock.c:252 ppp_channel_push+0x2c/0x220 drivers/net/ppp/ppp_generic.c:2185 ppp_write+0x291/0x390 drivers/net/ppp/ppp_generic.c:537 vfs_write+0x30c/0xe50 fs/read_write.c:592 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 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 } ... key at: [] ppp_register_net_channel.__key.3+0x0/0x20 -> (&ppp->wlock){+...}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_get_stats64+0xbf/0x290 drivers/net/ppp/ppp_generic.c:1538 dev_get_stats+0x90/0x370 net/core/dev.c:10704 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1205 rtnl_fill_ifinfo+0x1598/0x1d60 net/core/rtnetlink.c:1782 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3856 rtmsg_ifinfo_event net/core/rtnetlink.c:3888 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3897 register_netdevice+0x13d2/0x1720 net/core/dev.c:10402 ppp_unit_register drivers/net/ppp/ppp_generic.c:1216 [inline] ppp_dev_configure+0x853/0xad0 drivers/net/ppp/ppp_generic.c:1272 ppp_create_interface drivers/net/ppp/ppp_generic.c:3347 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1057 [inline] ppp_ioctl+0x702/0x1cd0 drivers/net/ppp/ppp_generic.c:730 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 INITIAL USE at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_get_stats64+0xbf/0x290 drivers/net/ppp/ppp_generic.c:1538 dev_get_stats+0x90/0x370 net/core/dev.c:10704 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1205 rtnl_fill_ifinfo+0x1598/0x1d60 net/core/rtnetlink.c:1782 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3856 rtmsg_ifinfo_event net/core/rtnetlink.c:3888 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3897 register_netdevice+0x13d2/0x1720 net/core/dev.c:10402 ppp_unit_register drivers/net/ppp/ppp_generic.c:1216 [inline] ppp_dev_configure+0x853/0xad0 drivers/net/ppp/ppp_generic.c:1272 ppp_create_interface drivers/net/ppp/ppp_generic.c:3347 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1057 [inline] ppp_ioctl+0x702/0x1cd0 drivers/net/ppp/ppp_generic.c:730 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 } ... key at: [] ppp_dev_configure.__key.62+0x0/0x20 ... acquired at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_connect_channel+0x170/0x640 drivers/net/ppp/ppp_generic.c:3483 ppp_ioctl+0xbe5/0x1cd0 drivers/net/ppp/ppp_generic.c:758 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 -> (&ppp->rlock){+...}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_get_stats64+0x2f/0x290 drivers/net/ppp/ppp_generic.c:1533 dev_get_stats+0x90/0x370 net/core/dev.c:10704 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1205 rtnl_fill_ifinfo+0x1598/0x1d60 net/core/rtnetlink.c:1782 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3856 rtmsg_ifinfo_event net/core/rtnetlink.c:3888 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3897 register_netdevice+0x13d2/0x1720 net/core/dev.c:10402 ppp_unit_register drivers/net/ppp/ppp_generic.c:1216 [inline] ppp_dev_configure+0x853/0xad0 drivers/net/ppp/ppp_generic.c:1272 ppp_create_interface drivers/net/ppp/ppp_generic.c:3347 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1057 [inline] ppp_ioctl+0x702/0x1cd0 drivers/net/ppp/ppp_generic.c:730 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 INITIAL USE at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_get_stats64+0x2f/0x290 drivers/net/ppp/ppp_generic.c:1533 dev_get_stats+0x90/0x370 net/core/dev.c:10704 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1205 rtnl_fill_ifinfo+0x1598/0x1d60 net/core/rtnetlink.c:1782 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3856 rtmsg_ifinfo_event net/core/rtnetlink.c:3888 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3897 register_netdevice+0x13d2/0x1720 net/core/dev.c:10402 ppp_unit_register drivers/net/ppp/ppp_generic.c:1216 [inline] ppp_dev_configure+0x853/0xad0 drivers/net/ppp/ppp_generic.c:1272 ppp_create_interface drivers/net/ppp/ppp_generic.c:3347 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1057 [inline] ppp_ioctl+0x702/0x1cd0 drivers/net/ppp/ppp_generic.c:730 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 } ... key at: [] ppp_dev_configure.__key+0x0/0x20 ... acquired at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_ioctl+0x1684/0x1cd0 drivers/net/ppp/ppp_generic.c:820 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 the dependencies between the lock to be acquired and SOFTIRQ-READ-irq-unsafe lock: -> (&pch->downl){+.+.}-{2:2} { HARDIRQ-ON-W 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_push+0x31/0x1d0 drivers/net/ppp/ppp_generic.c:2160 ppp_channel_push+0x196/0x220 drivers/net/ppp/ppp_generic.c:2191 ppp_write+0x291/0x390 drivers/net/ppp/ppp_generic.c:537 vfs_write+0x30c/0xe50 fs/read_write.c:592 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 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 SOFTIRQ-ON-W 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] __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 INITIAL USE 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_push+0x31/0x1d0 drivers/net/ppp/ppp_generic.c:2160 ppp_channel_push+0x196/0x220 drivers/net/ppp/ppp_generic.c:2191 ppp_write+0x291/0x390 drivers/net/ppp/ppp_generic.c:537 vfs_write+0x30c/0xe50 fs/read_write.c:592 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 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 } ... key at: [] ppp_register_net_channel.__key.1+0x0/0x20 ... acquired at: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_connect_channel+0x190/0x640 drivers/net/ppp/ppp_generic.c:3484 ppp_ioctl+0xbe5/0x1cd0 drivers/net/ppp/ppp_generic.c:758 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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 stack backtrace: CPU: 0 PID: 4263 Comm: syz.4.95 Not tainted 5.15.167-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 print_bad_irq_dependency kernel/locking/lockdep.c:2567 [inline] check_irq_usage kernel/locking/lockdep.c:2806 [inline] check_prev_add kernel/locking/lockdep.c:3057 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x4d01/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] ppp_connect_channel+0x190/0x640 drivers/net/ppp/ppp_generic.c:3484 ppp_ioctl+0xbe5/0x1cd0 drivers/net/ppp/ppp_generic.c:758 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 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: 0033:0x7f9ac7d15ef9 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:00007f9ac618e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9ac7ecdf80 RCX: 00007f9ac7d15ef9 RDX: 0000000020000300 RSI: 000000004004743a RDI: 0000000000000005 RBP: 00007f9ac7d88b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f9ac7ecdf80 R15: 00007fff661c8bb8