BUG: sleeping function called from invalid context at include/linux/sched/mm.h:209 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 20275, name: syz-executor.1 2 locks held by syz-executor.1/20275: #0: ffffffff8d9e0748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d9e0748 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5596 #1: ffff888021616108 (&sch->q.lock){+...}-{2:2}, at: netem_change+0x257/0x20c0 net/sched/sch_netem.c:972 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 1 PID: 20275 Comm: syz-executor.1 Not tainted 5.15.124-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 ___might_sleep+0x547/0x6a0 kernel/sched/core.c:9625 might_alloc include/linux/sched/mm.h:209 [inline] slab_pre_alloc_hook+0x44/0xc0 mm/slab.h:492 slab_alloc_node mm/slub.c:3134 [inline] __kmalloc_node+0x71/0x390 mm/slub.c:4451 kmalloc_node include/linux/slab.h:614 [inline] kvmalloc_node+0x80/0x140 mm/util.c:619 kvmalloc include/linux/mm.h:805 [inline] get_dist_table+0x83/0x2c0 net/sched/sch_netem.c:788 netem_change+0xa05/0x20c0 net/sched/sch_netem.c:988 netem_init+0x58/0xb0 net/sched/sch_netem.c:1075 qdisc_create+0x8ae/0x1390 net/sched/sch_api.c:1264 tc_modify_qdisc+0xac5/0x1710 rtnetlink_rcv_msg+0x993/0xee0 net/core/rtnetlink.c:5599 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2505 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1356 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1924 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2412 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2466 __sys_sendmsg net/socket.c:2495 [inline] __do_sys_sendmsg net/socket.c:2504 [inline] __se_sys_sendmsg+0x19a/0x260 net/socket.c:2502 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+0x61/0xcb RIP: 0033:0x7f878acabae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f878920c0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f878adcb050 RCX: 00007f878acabae9 RDX: 0000000000000000 RSI: 0000000020000440 RDI: 0000000000000003 RBP: 00007f878acf747a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f878adcb050 R15: 00007ffcc67189d8 ============================================ WARNING: possible recursive locking detected 5.15.124-syzkaller #0 Tainted: G W -------------------------------------------- syz-executor.1/20275 is trying to acquire lock: ffff888021616108 (&sch->q.lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] ffff888021616108 (&sch->q.lock){+...}-{2:2}, at: get_dist_table+0x1fa/0x2c0 net/sched/sch_netem.c:798 but task is already holding lock: ffff888021616108 (&sch->q.lock){+...}-{2:2}, at: netem_change+0x257/0x20c0 net/sched/sch_netem.c:972 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sch->q.lock); lock(&sch->q.lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor.1/20275: #0: ffffffff8d9e0748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d9e0748 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5596 #1: ffff888021616108 (&sch->q.lock){+...}-{2:2}, at: netem_change+0x257/0x20c0 net/sched/sch_netem.c:972 stack backtrace: CPU: 1 PID: 20275 Comm: syz-executor.1 Tainted: G W 5.15.124-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2946 [inline] check_deadlock kernel/locking/lockdep.c:2989 [inline] validate_chain+0x46cf/0x58b0 kernel/locking/lockdep.c:3774 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622 __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] get_dist_table+0x1fa/0x2c0 net/sched/sch_netem.c:798 netem_change+0xa05/0x20c0 net/sched/sch_netem.c:988 netem_init+0x58/0xb0 net/sched/sch_netem.c:1075 qdisc_create+0x8ae/0x1390 net/sched/sch_api.c:1264 tc_modify_qdisc+0xac5/0x1710 rtnetlink_rcv_msg+0x993/0xee0 net/core/rtnetlink.c:5599 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2505 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1356 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1924 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2412 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2466 __sys_sendmsg net/socket.c:2495 [inline] __do_sys_sendmsg net/socket.c:2504 [inline] __se_sys_sendmsg+0x19a/0x260 net/socket.c:2502 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+0x61/0xcb RIP: 0033:0x7f878acabae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f878920c0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f878adcb050 RCX: 00007f878acabae9 RDX: 0000000000000000 RSI: 0000000020000440 RDI: 0000000000000003 RBP: 00007f878acf747a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f878adcb050 R15: 00007ffcc67189d8