possible deadlock in ppp

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	possible deadlock in ppp_input ppp				114	27m	11d	0/28	upstream: reported on 2024/09/17 11:45
linux-5.15	possible deadlock in ppp_input				9	7h50m	13d	0/3	upstream: reported on 2024/09/14 14:35

===================================================== WARNING: SOFTIRQ-READ-safe -> SOFTIRQ-READ-unsafe lock order detected 6.1.111-syzkaller #0 Not tainted ----------------------------------------------------- syz.2.269/5482 [HC0[0]:SC0[8]:HE1:SE0] is trying to acquire: ffff8880268541e0 (&pch->downl){+.+.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff8880268541e0 (&pch->downl){+.+.}-{2:2}, at: ppp_connect_channel+0x190/0x640 drivers/net/ppp/ppp_generic.c:3485 and this task is already holding: ffff8880663a0dd0 (&ppp->rlock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] (&ppp->rlock){+...}-{2:2}, at: ppp_connect_channel+0x181/0x640 drivers/net/ppp/ppp_generic.c:3484 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+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __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+0x3ca/0xa00 drivers/net/ppp/ppp_generic.c:2307 ppp_async_process+0x7b/0x140 drivers/net/ppp/ppp_async.c:503 tasklet_action_common+0x3cb/0x4a0 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 run_ksoftirqd+0xc6/0x120 kernel/softirq.c:938 smpboot_thread_fn+0x52c/0xa30 kernel/smpboot.c:164 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 to a SOFTIRQ-READ-irq-unsafe lock: (&pch->downl){+.+.}-{2:2} ... which became SOFTIRQ-READ-irq-unsafe at: ... lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/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+0x185/0xa00 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x112/0x300 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1117 [inline] __release_sock+0x198/0x4b0 net/core/sock.c:2936 release_sock+0x5d/0x1c0 net/core/sock.c:3500 pppoe_sendmsg+0xd1/0x740 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514 ___sys_sendmsg net/socket.c:2568 [inline] __sys_sendmmsg+0x3ab/0x730 net/socket.c:2654 __do_sys_sendmmsg net/socket.c:2683 [inline] __se_sys_sendmmsg net/socket.c:2680 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2680 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 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); <Interrupt> lock(&pch->upl); *** DEADLOCK *** 5 locks held by syz.2.269/5482: #0: ffffffff8dd6c148 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x10e/0x1c90 drivers/net/ppp/ppp_generic.c:727 #1: ffff888058ac2cc0 (&pn->all_ppp_mutex){+.+.}-{3:3}, at: ppp_connect_channel+0x5e/0x640 drivers/net/ppp/ppp_generic.c:3474 #2: ffff888026854248 (&pch->upl){++.-}-{2:2}, at: ppp_connect_channel+0x87/0x640 drivers/net/ppp/ppp_generic.c:3478 #3: ffff8880663a0e10 (&ppp->wlock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #3: ffff8880663a0e10 (&ppp->wlock){+...}-{2:2}, at: ppp_connect_channel+0x170/0x640 drivers/net/ppp/ppp_generic.c:3484 #4: ffff8880663a0dd0 (&ppp->rlock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #4: ffff8880663a0dd0 (&ppp->rlock){+...}-{2:2}, at: ppp_connect_channel+0x181/0x640 drivers/net/ppp/ppp_generic.c:3484 the dependencies between SOFTIRQ-READ-irq-safe lock and the holding lock: -> (&pch->upl){++.-}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:334 ppp_disconnect_channel+0x2f/0x2d0 drivers/net/ppp/ppp_generic.c:3522 ppp_unregister_channel+0xb5/0x2f0 drivers/net/ppp/ppp_generic.c:2996 pppox_unbind_sock+0x58/0xa0 drivers/net/ppp/pppox.c:58 pptp_release+0x143/0x2f0 drivers/net/ppp/pptp.c:519 __sock_release net/socket.c:654 [inline] sock_close+0xcd/0x230 net/socket.c:1400 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 HARDIRQ-ON-R at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __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:2186 ppp_write+0x294/0x3a0 drivers/net/ppp/ppp_generic.c:538 vfs_write+0x2d9/0xbc0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 IN-SOFTIRQ-R at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __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+0x3ca/0xa00 drivers/net/ppp/ppp_generic.c:2307 ppp_async_process+0x7b/0x140 drivers/net/ppp/ppp_async.c:503 tasklet_action_common+0x3cb/0x4a0 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 run_ksoftirqd+0xc6/0x120 kernel/softirq.c:938 smpboot_thread_fn+0x52c/0xa30 kernel/smpboot.c:164 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INITIAL USE at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:334 ppp_disconnect_channel+0x2f/0x2d0 drivers/net/ppp/ppp_generic.c:3522 ppp_unregister_channel+0xb5/0x2f0 drivers/net/ppp/ppp_generic.c:2996 pppox_unbind_sock+0x58/0xa0 drivers/net/ppp/pppox.c:58 pptp_release+0x143/0x2f0 drivers/net/ppp/pptp.c:519 __sock_release net/socket.c:654 [inline] sock_close+0xcd/0x230 net/socket.c:1400 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 INITIAL READ USE at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __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:2186 ppp_write+0x294/0x3a0 drivers/net/ppp/ppp_generic.c:538 vfs_write+0x2d9/0xbc0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 } ... key at: [<ffffffff976db060>] ppp_register_net_channel.__key.3+0x0/0x20 -> (&ppp->wlock){+...}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_get_stats64+0xbf/0x290 drivers/net/ppp/ppp_generic.c:1539 dev_get_stats+0xa7/0x490 net/core/dev.c:10471 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1244 rtnl_fill_ifinfo+0x18aa/0x2090 net/core/rtnetlink.c:1825 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3938 rtmsg_ifinfo_event net/core/rtnetlink.c:3970 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3979 register_netdevice+0x13dc/0x1720 net/core/dev.c:10146 ppp_unit_register drivers/net/ppp/ppp_generic.c:1217 [inline] ppp_dev_configure+0x850/0xab0 drivers/net/ppp/ppp_generic.c:1273 ppp_create_interface drivers/net/ppp/ppp_generic.c:3348 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1058 [inline] ppp_ioctl+0x702/0x1c90 drivers/net/ppp/ppp_generic.c:731 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 INITIAL USE at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_get_stats64+0xbf/0x290 drivers/net/ppp/ppp_generic.c:1539 dev_get_stats+0xa7/0x490 net/core/dev.c:10471 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1244 rtnl_fill_ifinfo+0x18aa/0x2090 net/core/rtnetlink.c:1825 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3938 rtmsg_ifinfo_event net/core/rtnetlink.c:3970 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3979 register_netdevice+0x13dc/0x1720 net/core/dev.c:10146 ppp_unit_register drivers/net/ppp/ppp_generic.c:1217 [inline] ppp_dev_configure+0x850/0xab0 drivers/net/ppp/ppp_generic.c:1273 ppp_create_interface drivers/net/ppp/ppp_generic.c:3348 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1058 [inline] ppp_ioctl+0x702/0x1c90 drivers/net/ppp/ppp_generic.c:731 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 } ... key at: [<ffffffff976db1a0>] ppp_dev_configure.__key.65+0x0/0x20 ... acquired at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_connect_channel+0x170/0x640 drivers/net/ppp/ppp_generic.c:3484 ppp_ioctl+0xbe5/0x1c90 drivers/net/ppp/ppp_generic.c:759 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> (&ppp->rlock){+...}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_get_stats64+0x2f/0x290 drivers/net/ppp/ppp_generic.c:1534 dev_get_stats+0xa7/0x490 net/core/dev.c:10471 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1244 rtnl_fill_ifinfo+0x18aa/0x2090 net/core/rtnetlink.c:1825 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3938 rtmsg_ifinfo_event net/core/rtnetlink.c:3970 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3979 register_netdevice+0x13dc/0x1720 net/core/dev.c:10146 ppp_unit_register drivers/net/ppp/ppp_generic.c:1217 [inline] ppp_dev_configure+0x850/0xab0 drivers/net/ppp/ppp_generic.c:1273 ppp_create_interface drivers/net/ppp/ppp_generic.c:3348 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1058 [inline] ppp_ioctl+0x702/0x1c90 drivers/net/ppp/ppp_generic.c:731 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 INITIAL USE at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_get_stats64+0x2f/0x290 drivers/net/ppp/ppp_generic.c:1534 dev_get_stats+0xa7/0x490 net/core/dev.c:10471 rtnl_fill_stats+0x47/0x880 net/core/rtnetlink.c:1244 rtnl_fill_ifinfo+0x18aa/0x2090 net/core/rtnetlink.c:1825 rtmsg_ifinfo_build_skb+0xdc/0x180 net/core/rtnetlink.c:3938 rtmsg_ifinfo_event net/core/rtnetlink.c:3970 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3979 register_netdevice+0x13dc/0x1720 net/core/dev.c:10146 ppp_unit_register drivers/net/ppp/ppp_generic.c:1217 [inline] ppp_dev_configure+0x850/0xab0 drivers/net/ppp/ppp_generic.c:1273 ppp_create_interface drivers/net/ppp/ppp_generic.c:3348 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1058 [inline] ppp_ioctl+0x702/0x1c90 drivers/net/ppp/ppp_generic.c:731 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 } ... key at: [<ffffffff976db180>] ppp_dev_configure.__key+0x0/0x20 ... acquired at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_connect_channel+0x181/0x640 drivers/net/ppp/ppp_generic.c:3484 ppp_ioctl+0xbe5/0x1c90 drivers/net/ppp/ppp_generic.c:759 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 the dependencies between the lock to be acquired and SOFTIRQ-READ-irq-unsafe lock: -> (&pch->downl){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_unregister_channel+0x78/0x2f0 drivers/net/ppp/ppp_generic.c:2992 pppox_unbind_sock+0x58/0xa0 drivers/net/ppp/pppox.c:58 pptp_release+0x143/0x2f0 drivers/net/ppp/pptp.c:519 __sock_release net/socket.c:654 [inline] sock_close+0xcd/0x230 net/socket.c:1400 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 SOFTIRQ-ON-W at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/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+0x185/0xa00 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x112/0x300 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv include/net/sock.h:1117 [inline] __release_sock+0x198/0x4b0 net/core/sock.c:2936 release_sock+0x5d/0x1c0 net/core/sock.c:3500 pppoe_sendmsg+0xd1/0x740 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514 ___sys_sendmsg net/socket.c:2568 [inline] __sys_sendmmsg+0x3ab/0x730 net/socket.c:2654 __do_sys_sendmmsg net/socket.c:2683 [inline] __se_sys_sendmmsg net/socket.c:2680 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2680 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 INITIAL USE at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_unregister_channel+0x78/0x2f0 drivers/net/ppp/ppp_generic.c:2992 pppox_unbind_sock+0x58/0xa0 drivers/net/ppp/pppox.c:58 pptp_release+0x143/0x2f0 drivers/net/ppp/pptp.c:519 __sock_release net/socket.c:654 [inline] sock_close+0xcd/0x230 net/socket.c:1400 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 } ... key at: [<ffffffff976db040>] ppp_register_net_channel.__key.1+0x0/0x20 ... acquired at: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_connect_channel+0x190/0x640 drivers/net/ppp/ppp_generic.c:3485 ppp_ioctl+0xbe5/0x1c90 drivers/net/ppp/ppp_generic.c:759 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 stack backtrace: CPU: 0 PID: 5482 Comm: syz.2.269 Not tainted 6.1.111-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_bad_irq_dependency kernel/locking/lockdep.c:2604 [inline] check_irq_usage kernel/locking/lockdep.c:2843 [inline] check_prev_add kernel/locking/lockdep.c:3094 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x4d16/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] ppp_connect_channel+0x190/0x640 drivers/net/ppp/ppp_generic.c:3485 ppp_ioctl+0xbe5/0x1c90 drivers/net/ppp/ppp_generic.c:759 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f117197dff9 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:00007f11726f3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1171b35f80 RCX: 00007f117197dff9 RDX: 0000000020000300 RSI: 000000004004743a RDI: 0000000000000005 RBP: 00007f11719f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1171b35f80 R15: 00007ffd1700a5b8 </TASK>

Crashes (2):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2024/09/27 23:12	linux-6.1.y	e526b12bf916	440b26ec	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-1-kasan	possible deadlock in ppp_input
2024/09/25 02:51	linux-6.1.y	e526b12bf916	5643e0e9	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-1-kasan	possible deadlock in ppp_input

Crashes (2):

Assets (help?)