========================================================
WARNING: possible irq lock inversion dependency detected
6.11.0-rc7-syzkaller-g5f5673607153 #0 Not tainted
--------------------------------------------------------
ksoftirqd/1/24 just changed the state of lock:
ffff0000f2c20e10 (&ppp->rlock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff0000f2c20e10 (&ppp->rlock){+.-.}-{2:2}, at: ppp_do_recv+0x48/0x1fa4 drivers/net/ppp/ppp_generic.c:2210
but this lock took another, SOFTIRQ-unsafe lock in the past:
 (&pch->downl){+.+.}-{2:2}


and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&pch->downl);
                               local_irq_disable();
                               lock(&ppp->rlock);
                               lock(&pch->downl);
  <Interrupt>
    lock(&ppp->rlock);

 *** DEADLOCK ***

1 lock held by ksoftirqd/1/24:
 #0: ffff0000d13d8248 (&pch->upl){++.-}-{2:2}, at: ppp_input+0x34c/0x854 drivers/net/ppp/ppp_generic.c:2307

the shortest dependencies between 2nd lock and 1st lock:
 -> (&pch->downl){+.+.}-{2:2} {
    HARDIRQ-ON-W at:
                      lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
                      __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
                      _raw_spin_lock+0x48/0x60 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+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
                      pppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379
                      sk_backlog_rcv include/net/sock.h:1111 [inline]
                      __release_sock+0x1a8/0x3d8 net/core/sock.c:3004
                      release_sock+0x68/0x1b8 net/core/sock.c:3558
                      pppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903
                      sock_sendmsg_nosec net/socket.c:730 [inline]
                      __sock_sendmsg net/socket.c:745 [inline]
                      ____sys_sendmsg+0x56c/0x840 net/socket.c:2597
                      ___sys_sendmsg net/socket.c:2651 [inline]
                      __sys_sendmmsg+0x318/0x7e0 net/socket.c:2737
                      __do_sys_sendmmsg net/socket.c:2766 [inline]
                      __se_sys_sendmmsg net/socket.c:2763 [inline]
                      __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2763
                      __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
                      invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
                      el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
                      do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
                      el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
                      el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
                      el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
    SOFTIRQ-ON-W at:
                      lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
                      __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
                      _raw_spin_lock+0x48/0x60 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+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
                      pppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379
                      sk_backlog_rcv include/net/sock.h:1111 [inline]
                      __release_sock+0x1a8/0x3d8 net/core/sock.c:3004
                      release_sock+0x68/0x1b8 net/core/sock.c:3558
                      pppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903
                      sock_sendmsg_nosec net/socket.c:730 [inline]
                      __sock_sendmsg net/socket.c:745 [inline]
                      ____sys_sendmsg+0x56c/0x840 net/socket.c:2597
                      ___sys_sendmsg net/socket.c:2651 [inline]
                      __sys_sendmmsg+0x318/0x7e0 net/socket.c:2737
                      __do_sys_sendmmsg net/socket.c:2766 [inline]
                      __se_sys_sendmmsg net/socket.c:2763 [inline]
                      __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2763
                      __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
                      invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
                      el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
                      do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
                      el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
                      el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
                      el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
    INITIAL USE at:
                     lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
                     __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
                     _raw_spin_lock+0x48/0x60 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+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
                     pppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379
                     sk_backlog_rcv include/net/sock.h:1111 [inline]
                     __release_sock+0x1a8/0x3d8 net/core/sock.c:3004
                     release_sock+0x68/0x1b8 net/core/sock.c:3558
                     pppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903
                     sock_sendmsg_nosec net/socket.c:730 [inline]
                     __sock_sendmsg net/socket.c:745 [inline]
                     ____sys_sendmsg+0x56c/0x840 net/socket.c:2597
                     ___sys_sendmsg net/socket.c:2651 [inline]
                     __sys_sendmmsg+0x318/0x7e0 net/socket.c:2737
                     __do_sys_sendmmsg net/socket.c:2766 [inline]
                     __se_sys_sendmmsg net/socket.c:2763 [inline]
                     __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2763
                     __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
                     invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
                     el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
                     do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
                     el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
                     el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
                     el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
  }
  ... key      at: [<ffff8000973b90a0>] ppp_register_net_channel.__key.1+0x0/0x20
  ... acquired at:
   __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
   _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
   spin_lock_bh include/linux/spinlock.h:356 [inline]
   ppp_connect_channel+0x160/0x570 drivers/net/ppp/ppp_generic.c:3485
   ppp_ioctl+0x1424/0x2534 drivers/net/ppp/ppp_generic.c:761
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:907 [inline]
   __se_sys_ioctl fs/ioctl.c:893 [inline]
   __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893
   __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
   invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
   el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
   do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
   el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
   el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
   el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

-> (&ppp->rlock){+.-.}-{2:2} {
   HARDIRQ-ON-W at:
                    lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
                    __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
                    _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
                    spin_lock_bh include/linux/spinlock.h:356 [inline]
                    ppp_get_stats64+0x3c/0x268 drivers/net/ppp/ppp_generic.c:1534
                    dev_get_stats+0xac/0x6a4 net/core/dev.c:10894
                    rtnl_fill_stats+0x50/0x7c0 net/core/rtnetlink.c:1268
                    rtnl_fill_ifinfo+0x1504/0x1dc0 net/core/rtnetlink.c:1909
                    rtmsg_ifinfo_build_skb+0x178/0x25c net/core/rtnetlink.c:4079
                    rtmsg_ifinfo_event net/core/rtnetlink.c:4113 [inline]
                    rtmsg_ifinfo+0xa0/0x188 net/core/rtnetlink.c:4122
                    register_netdevice+0xea4/0x11a8 net/core/dev.c:10491
                    ppp_unit_register drivers/net/ppp/ppp_generic.c:1219 [inline]
                    ppp_dev_configure+0x6c4/0x944 drivers/net/ppp/ppp_generic.c:1275
                    ppp_create_interface drivers/net/ppp/ppp_generic.c:3348 [inline]
                    ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1060 [inline]
                    ppp_ioctl+0x9d0/0x2534 drivers/net/ppp/ppp_generic.c:733
                    vfs_ioctl fs/ioctl.c:51 [inline]
                    __do_sys_ioctl fs/ioctl.c:907 [inline]
                    __se_sys_ioctl fs/ioctl.c:893 [inline]
                    __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893
                    __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
                    invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
                    el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
                    do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
                    el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
                    el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
                    el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
   IN-SOFTIRQ-W at:
                    lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
                    __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
                    _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
                    spin_lock_bh include/linux/spinlock.h:356 [inline]
                    ppp_do_recv+0x48/0x1fa4 drivers/net/ppp/ppp_generic.c:2210
                    ppp_input+0x4c0/0x854 drivers/net/ppp/ppp_generic.c:2327
                    ppp_async_process+0x98/0x150 drivers/net/ppp/ppp_async.c:495
                    tasklet_action_common+0x318/0x3f4 kernel/softirq.c:785
                    tasklet_action+0x68/0x8c kernel/softirq.c:811
                    handle_softirqs+0x2e4/0xbfc kernel/softirq.c:554
                    run_ksoftirqd+0x70/0x158 kernel/softirq.c:928
                    smpboot_thread_fn+0x4b0/0x90c kernel/smpboot.c:164
                    kthread+0x288/0x310 kernel/kthread.c:389
                    ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860
   INITIAL USE at:
                   lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
                   __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
                   _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
                   spin_lock_bh include/linux/spinlock.h:356 [inline]
                   ppp_get_stats64+0x3c/0x268 drivers/net/ppp/ppp_generic.c:1534
                   dev_get_stats+0xac/0x6a4 net/core/dev.c:10894
                   rtnl_fill_stats+0x50/0x7c0 net/core/rtnetlink.c:1268
                   rtnl_fill_ifinfo+0x1504/0x1dc0 net/core/rtnetlink.c:1909
                   rtmsg_ifinfo_build_skb+0x178/0x25c net/core/rtnetlink.c:4079
                   rtmsg_ifinfo_event net/core/rtnetlink.c:4113 [inline]
                   rtmsg_ifinfo+0xa0/0x188 net/core/rtnetlink.c:4122
                   register_netdevice+0xea4/0x11a8 net/core/dev.c:10491
                   ppp_unit_register drivers/net/ppp/ppp_generic.c:1219 [inline]
                   ppp_dev_configure+0x6c4/0x944 drivers/net/ppp/ppp_generic.c:1275
                   ppp_create_interface drivers/net/ppp/ppp_generic.c:3348 [inline]
                   ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1060 [inline]
                   ppp_ioctl+0x9d0/0x2534 drivers/net/ppp/ppp_generic.c:733
                   vfs_ioctl fs/ioctl.c:51 [inline]
                   __do_sys_ioctl fs/ioctl.c:907 [inline]
                   __se_sys_ioctl fs/ioctl.c:893 [inline]
                   __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893
                   __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
                   invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
                   el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
                   do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
                   el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
                   el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
                   el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
 }
 ... key      at: [<ffff8000973b91c0>] ppp_dev_configure.__key+0x0/0x20
 ... acquired at:
   mark_lock+0x258/0x360 kernel/locking/lockdep.c:4677
   __lock_acquire+0xf48/0x779c kernel/locking/lockdep.c:5096
   lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
   __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
   _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
   spin_lock_bh include/linux/spinlock.h:356 [inline]
   ppp_do_recv+0x48/0x1fa4 drivers/net/ppp/ppp_generic.c:2210
   ppp_input+0x4c0/0x854 drivers/net/ppp/ppp_generic.c:2327
   ppp_async_process+0x98/0x150 drivers/net/ppp/ppp_async.c:495
   tasklet_action_common+0x318/0x3f4 kernel/softirq.c:785
   tasklet_action+0x68/0x8c kernel/softirq.c:811
   handle_softirqs+0x2e4/0xbfc kernel/softirq.c:554
   run_ksoftirqd+0x70/0x158 kernel/softirq.c:928
   smpboot_thread_fn+0x4b0/0x90c kernel/smpboot.c:164
   kthread+0x288/0x310 kernel/kthread.c:389
   ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860


stack backtrace:
CPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.11.0-rc7-syzkaller-g5f5673607153 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:319
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:326
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:119
 dump_stack+0x1c/0x28 lib/dump_stack.c:128
 print_irq_inversion_bug+0x334/0x38c kernel/locking/lockdep.c:4079
 mark_lock_irq+0x8b0/0xd2c
 mark_lock+0x258/0x360 kernel/locking/lockdep.c:4677
 __lock_acquire+0xf48/0x779c kernel/locking/lockdep.c:5096
 lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 ppp_do_recv+0x48/0x1fa4 drivers/net/ppp/ppp_generic.c:2210
 ppp_input+0x4c0/0x854 drivers/net/ppp/ppp_generic.c:2327
 ppp_async_process+0x98/0x150 drivers/net/ppp/ppp_async.c:495
 tasklet_action_common+0x318/0x3f4 kernel/softirq.c:785
 tasklet_action+0x68/0x8c kernel/softirq.c:811
 handle_softirqs+0x2e4/0xbfc kernel/softirq.c:554
 run_ksoftirqd+0x70/0x158 kernel/softirq.c:928
 smpboot_thread_fn+0x4b0/0x90c kernel/smpboot.c:164
 kthread+0x288/0x310 kernel/kthread.c:389
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860