syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
6.1.37-syzkaller #0 Not tainted
-----------------------------------------------------
syz-executor192/3552 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire:
ffffffff8d0002e0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:271 [inline]
ffffffff8d0002e0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710

and this task is already holding:
ffffffff8e0db488 (noop_qdisc.q.lock){+.-.}-{2:2}, at: netem_change+0x17e/0x1ea0 net/sched/sch_netem.c:969
which would create a new lock dependency:
 (noop_qdisc.q.lock){+.-.}-{2:2} -> (fs_reclaim){+.+.}-{0:0}

but this new dependency connects a SOFTIRQ-irq-safe lock:
 (noop_qdisc.q.lock){+.-.}-{2:2}

... which became SOFTIRQ-irq-safe at:
  lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
  __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:350 [inline]
  net_tx_action+0x752/0x970 net/core/dev.c:5077
  __do_softirq+0x2e9/0xa4c kernel/softirq.c:571
  do_softirq+0x162/0x240 kernel/softirq.c:472
  __local_bh_enable_ip+0x1b1/0x1f0 kernel/softirq.c:396
  netif_tx_unlock_bh include/linux/netdevice.h:4396 [inline]
  dev_watchdog_down net/sched/sch_generic.c:566 [inline]
  dev_deactivate_many+0x3b4/0xaf0 net/sched/sch_generic.c:1348
  dev_deactivate+0x177/0x270 net/sched/sch_generic.c:1382
  linkwatch_do_dev+0x104/0x160 net/core/link_watch.c:166
  __linkwatch_run_queue+0x448/0x6b0 net/core/link_watch.c:221
  linkwatch_event+0x48/0x50 net/core/link_watch.c:264
  process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
  worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
  kthread+0x26e/0x300 kernel/kthread.c:376
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

to a SOFTIRQ-irq-unsafe lock:
 (fs_reclaim){+.+.}-{0:0}

... which became SOFTIRQ-irq-unsafe at:
...
  lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
  __fs_reclaim_acquire mm/page_alloc.c:4683 [inline]
  fs_reclaim_acquire+0x83/0x120 mm/page_alloc.c:4697
  might_alloc include/linux/sched/mm.h:271 [inline]
  slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710
  slab_alloc_node mm/slub.c:3318 [inline]
  __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
  kmalloc_trace+0x26/0xe0 mm/slab_common.c:1045
  kmalloc include/linux/slab.h:553 [inline]
  kzalloc include/linux/slab.h:689 [inline]
  alloc_workqueue_attrs+0x46/0xc0 kernel/workqueue.c:3394
  wq_numa_init+0x122/0x4b0 kernel/workqueue.c:5959
  workqueue_init+0x22/0x59d kernel/workqueue.c:6086
  kernel_init_freeable+0x40a/0x61f init/main.c:1614
  kernel_init+0x19/0x290 init/main.c:1519
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

other info that might help us debug this:

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               local_irq_disable();
                               lock(noop_qdisc.q.lock);
                               lock(fs_reclaim);
  <Interrupt>
    lock(noop_qdisc.q.lock);

 *** DEADLOCK ***

2 locks held by syz-executor192/3552:
 #0: ffffffff8e0949a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8e0949a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x720/0xf00 net/core/rtnetlink.c:6094
 #1: ffffffff8e0db488 (noop_qdisc.q.lock){+.-.}-{2:2}, at: netem_change+0x17e/0x1ea0 net/sched/sch_netem.c:969

the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (noop_qdisc.q.lock){+.-.}-{2:2} {
   HARDIRQ-ON-W at:
                    lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
                    __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:350 [inline]
                    __dev_xmit_skb net/core/dev.c:3854 [inline]
                    __dev_queue_xmit+0xd50/0x3c90 net/core/dev.c:4227
                    dev_queue_xmit include/linux/netdevice.h:3021 [inline]
                    tx+0x66/0x100 drivers/block/aoe/aoenet.c:63
                    kthread+0x234/0x440 drivers/block/aoe/aoecmd.c:1229
                    kthread+0x26e/0x300 kernel/kthread.c:376
                    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
   IN-SOFTIRQ-W at:
                    lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
                    __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:350 [inline]
                    net_tx_action+0x752/0x970 net/core/dev.c:5077
                    __do_softirq+0x2e9/0xa4c kernel/softirq.c:571
                    do_softirq+0x162/0x240 kernel/softirq.c:472
                    __local_bh_enable_ip+0x1b1/0x1f0 kernel/softirq.c:396
                    netif_tx_unlock_bh include/linux/netdevice.h:4396 [inline]
                    dev_watchdog_down net/sched/sch_generic.c:566 [inline]
                    dev_deactivate_many+0x3b4/0xaf0 net/sched/sch_generic.c:1348
                    dev_deactivate+0x177/0x270 net/sched/sch_generic.c:1382
                    linkwatch_do_dev+0x104/0x160 net/core/link_watch.c:166
                    __linkwatch_run_queue+0x448/0x6b0 net/core/link_watch.c:221
                    linkwatch_event+0x48/0x50 net/core/link_watch.c:264
                    process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
                    worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
                    kthread+0x26e/0x300 kernel/kthread.c:376
                    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
   INITIAL USE at:
                   lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
                   __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:350 [inline]
                   __dev_xmit_skb net/core/dev.c:3854 [inline]
                   __dev_queue_xmit+0xd50/0x3c90 net/core/dev.c:4227
                   dev_queue_xmit include/linux/netdevice.h:3021 [inline]
                   tx+0x66/0x100 drivers/block/aoe/aoenet.c:63
                   kthread+0x234/0x440 drivers/block/aoe/aoecmd.c:1229
                   kthread+0x26e/0x300 kernel/kthread.c:376
                   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 }
 ... key      at: [<ffffffff8e0db488>] noop_qdisc+0x108/0x320

the dependencies between the lock to be acquired
 and SOFTIRQ-irq-unsafe lock:
-> (fs_reclaim){+.+.}-{0:0} {
   HARDIRQ-ON-W at:
                    lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
                    __fs_reclaim_acquire mm/page_alloc.c:4683 [inline]
                    fs_reclaim_acquire+0x83/0x120 mm/page_alloc.c:4697
                    might_alloc include/linux/sched/mm.h:271 [inline]
                    slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710
                    slab_alloc_node mm/slub.c:3318 [inline]
                    __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
                    kmalloc_trace+0x26/0xe0 mm/slab_common.c:1045
                    kmalloc include/linux/slab.h:553 [inline]
                    kzalloc include/linux/slab.h:689 [inline]
                    alloc_workqueue_attrs+0x46/0xc0 kernel/workqueue.c:3394
                    wq_numa_init+0x122/0x4b0 kernel/workqueue.c:5959
                    workqueue_init+0x22/0x59d kernel/workqueue.c:6086
                    kernel_init_freeable+0x40a/0x61f init/main.c:1614
                    kernel_init+0x19/0x290 init/main.c:1519
                    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
   SOFTIRQ-ON-W at:
                    lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
                    __fs_reclaim_acquire mm/page_alloc.c:4683 [inline]
                    fs_reclaim_acquire+0x83/0x120 mm/page_alloc.c:4697
                    might_alloc include/linux/sched/mm.h:271 [inline]
                    slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710
                    slab_alloc_node mm/slub.c:3318 [inline]
                    __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
                    kmalloc_trace+0x26/0xe0 mm/slab_common.c:1045
                    kmalloc include/linux/slab.h:553 [inline]
                    kzalloc include/linux/slab.h:689 [inline]
                    alloc_workqueue_attrs+0x46/0xc0 kernel/workqueue.c:3394
                    wq_numa_init+0x122/0x4b0 kernel/workqueue.c:5959
                    workqueue_init+0x22/0x59d kernel/workqueue.c:6086
                    kernel_init_freeable+0x40a/0x61f init/main.c:1614
                    kernel_init+0x19/0x290 init/main.c:1519
                    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
   INITIAL USE at:
                   lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
                   __fs_reclaim_acquire mm/page_alloc.c:4683 [inline]
                   fs_reclaim_acquire+0x83/0x120 mm/page_alloc.c:4697
                   might_alloc include/linux/sched/mm.h:271 [inline]
                   slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710
                   slab_alloc_node mm/slub.c:3318 [inline]
                   __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
                   kmalloc_trace+0x26/0xe0 mm/slab_common.c:1045
                   kmalloc include/linux/slab.h:553 [inline]
                   kzalloc include/linux/slab.h:689 [inline]
                   alloc_workqueue_attrs+0x46/0xc0 kernel/workqueue.c:3394
                   wq_numa_init+0x122/0x4b0 kernel/workqueue.c:5959
                   workqueue_init+0x22/0x59d kernel/workqueue.c:6086
                   kernel_init_freeable+0x40a/0x61f init/main.c:1614
                   kernel_init+0x19/0x290 init/main.c:1519
                   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 }
 ... key      at: [<ffffffff8d0002e0>] __fs_reclaim_map+0x0/0xe0
 ... acquired at:
   lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
   __fs_reclaim_acquire mm/page_alloc.c:4683 [inline]
   fs_reclaim_acquire+0x83/0x120 mm/page_alloc.c:4697
   might_alloc include/linux/sched/mm.h:271 [inline]
   slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710
   slab_alloc_node mm/slub.c:3318 [inline]
   __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
   __do_kmalloc_node mm/slab_common.c:954 [inline]
   __kmalloc_node+0xa2/0x230 mm/slab_common.c:962
   kmalloc_node include/linux/slab.h:579 [inline]
   kvmalloc_node+0x6e/0x180 mm/util.c:581
   kvmalloc include/linux/slab.h:706 [inline]
   get_dist_table+0x91/0x380 net/sched/sch_netem.c:788
   netem_change+0x947/0x1ea0 net/sched/sch_netem.c:985
   netem_init+0x58/0xb0 net/sched/sch_netem.c:1072
   qdisc_create+0x8a1/0x1220 net/sched/sch_api.c:1314
   tc_modify_qdisc+0x9e0/0x1da0 net/sched/sch_api.c:1723
   rtnetlink_rcv_msg+0x776/0xf00 net/core/rtnetlink.c:6097
   netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2524
   netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
   netlink_unicast+0x7bf/0x990 net/netlink/af_netlink.c:1354
   netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1902
   sock_sendmsg_nosec net/socket.c:716 [inline]
   sock_sendmsg net/socket.c:736 [inline]
   ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
   ___sys_sendmsg net/socket.c:2536 [inline]
   __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x63/0xcd


stack backtrace:
CPU: 0 PID: 3552 Comm: syz-executor192 Not tainted 6.1.37-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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:2612 [inline]
 check_irq_usage kernel/locking/lockdep.c:2851 [inline]
 check_prev_add kernel/locking/lockdep.c:3102 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain+0x4d2e/0x58e0 kernel/locking/lockdep.c:3832
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
 __fs_reclaim_acquire mm/page_alloc.c:4683 [inline]
 fs_reclaim_acquire+0x83/0x120 mm/page_alloc.c:4697
 might_alloc include/linux/sched/mm.h:271 [inline]
 slab_pre_alloc_hook+0x2a/0x2a0 mm/slab.h:710
 slab_alloc_node mm/slub.c:3318 [inline]
 __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:954 [inline]
 __kmalloc_node+0xa2/0x230 mm/slab_common.c:962
 kmalloc_node include/linux/slab.h:579 [inline]
 kvmalloc_node+0x6e/0x180 mm/util.c:581
 kvmalloc include/linux/slab.h:706 [inline]
 get_dist_table+0x91/0x380 net/sched/sch_netem.c:788
 netem_change+0x947/0x1ea0 net/sched/sch_netem.c:985
 netem_init+0x58/0xb0 net/sched/sch_netem.c:1072
 qdisc_create+0x8a1/0x1220 net/sched/sch_api.c:1314
 tc_modify_qdisc+0x9e0/0x1da0 net/sched/sch_api.c:1723
 rtnetlink_rcv_msg+0x776/0xf00 net/core/rtnetlink.c:6097
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2524
 netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
 netlink_unicast+0x7bf/0x990 net/netlink/af_netlink.c:1354
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1902
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc6e33c21f9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcd4edfc98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc6e33c21f9
RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000003
RBP: 00007fc6e33861e0 R08: 00000000ffffffff R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fc6e3386270
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 3552, name: syz-executor192
preempt_count: 201, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 PID: 3552 Comm: syz-executor192 Not tainted 6.1.37-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 __might_resched+0x5cb/0x780 kernel/sched/core.c:9941
 might_alloc include/linux/sched/mm.h:274 [inline]
 slab_pre_alloc_hook+0x4a/0x2a0 mm/slab.h:710
 slab_alloc_node mm/slub.c:3318 [inline]
 __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:954 [inline]
 __kmalloc_node+0xa2/0x230 mm/slab_common.c:962
 kmalloc_node include/linux/slab.h:579 [inline]
 kvmalloc_node+0x6e/0x180 mm/util.c:581
 kvmalloc include/linux/slab.h:706 [inline]
 get_dist_table+0x91/0x380 net/sched/sch_netem.c:788
 netem_change+0x947/0x1ea0 net/sched/sch_netem.c:985
 netem_init+0x58/0xb0 net/sched/sch_netem.c:1072
 qdisc_create+0x8a1/0x1220 net/sched/sch_api.c:1314
 tc_modify_qdisc+0x9e0/0x1da0 net/sched/sch_api.c:1723
 rtnetlink_rcv_msg+0x776/0xf00 net/core/rtnetlink.c:6097
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2524
 netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
 netlink_unicast+0x7bf/0x990 net/netlink/af_netlink.c:1354
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1902
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc6e33c21f9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcd4edfc98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc6e33c21f9
RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000003
RBP: 00007fc6e33861e0 R08: 00000000ffffffff R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fc6e3386270
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>