BUG: sleeping function called from invalid context at include/linux/sched/mm.h:209 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 3963, name: syz-executor929 2 locks held by syz-executor929/3963: #0: ffff8000169e74a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffff8000169e74a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0xa2c/0xdac net/core/rtnetlink.c:5600 #1: ffff0000d8631108 (&sch->q.lock){+...}-{2:2}, at: netem_change+0x22c/0x1a90 net/sched/sch_netem.c:972 Preemption disabled at: [] netem_change+0x22c/0x1a90 net/sched/sch_netem.c:972 CPU: 1 PID: 3963 Comm: syz-executor929 Not tainted 5.15.126-syzkaller-00092-g24c4de4069cb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 ___might_sleep+0x380/0x4dc kernel/sched/core.c:9625 __might_sleep+0x98/0xf0 kernel/sched/core.c:9579 might_alloc include/linux/sched/mm.h:209 [inline] slab_pre_alloc_hook+0x58/0xe8 mm/slab.h:492 slab_alloc_node mm/slub.c:3134 [inline] __kmalloc_node+0xbc/0x5b8 mm/slub.c:4451 kmalloc_node include/linux/slab.h:614 [inline] kvmalloc_node+0x88/0x204 mm/util.c:619 kvmalloc include/linux/mm.h:805 [inline] get_dist_table+0x9c/0x2a4 net/sched/sch_netem.c:788 netem_change+0x7cc/0x1a90 net/sched/sch_netem.c:988 netem_init+0x54/0xb8 net/sched/sch_netem.c:1075 qdisc_create+0x6fc/0xf44 net/sched/sch_api.c:1264 tc_modify_qdisc+0x8dc/0x1344 rtnetlink_rcv_msg+0xa74/0xdac net/core/rtnetlink.c:5603 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2505 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5621 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1924 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x584/0x870 net/socket.c:2412 ___sys_sendmsg+0x214/0x294 net/socket.c:2466 __sys_sendmsg net/socket.c:2495 [inline] __do_sys_sendmsg net/socket.c:2504 [inline] __se_sys_sendmsg net/socket.c:2502 [inline] __arm64_sys_sendmsg+0x1ac/0x25c net/socket.c:2502 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 ============================================ WARNING: possible recursive locking detected 5.15.126-syzkaller-00092-g24c4de4069cb #0 Tainted: G W -------------------------------------------- syz-executor929/3963 is trying to acquire lock: ffff0000d8631108 (&sch->q.lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline] ffff0000d8631108 (&sch->q.lock){+...}-{2:2}, at: get_dist_table+0x1f0/0x2a4 net/sched/sch_netem.c:798 but task is already holding lock: ffff0000d8631108 (&sch->q.lock){+...}-{2:2}, at: netem_change+0x22c/0x1a90 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-executor929/3963: #0: ffff8000169e74a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffff8000169e74a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0xa2c/0xdac net/core/rtnetlink.c:5600 #1: ffff0000d8631108 (&sch->q.lock){+...}-{2:2}, at: netem_change+0x22c/0x1a90 net/sched/sch_netem.c:972 stack backtrace: CPU: 1 PID: 3963 Comm: syz-executor929 Tainted: G W 5.15.126-syzkaller-00092-g24c4de4069cb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 __lock_acquire+0x62b4/0x7620 kernel/locking/lockdep.c:5011 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x124/0x1c4 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:368 [inline] get_dist_table+0x1f0/0x2a4 net/sched/sch_netem.c:798 netem_change+0x7cc/0x1a90 net/sched/sch_netem.c:988 netem_init+0x54/0xb8 net/sched/sch_netem.c:1075 qdisc_create+0x6fc/0xf44 net/sched/sch_api.c:1264 tc_modify_qdisc+0x8dc/0x1344 rtnetlink_rcv_msg+0xa74/0xdac net/core/rtnetlink.c:5603 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2505 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5621 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1924 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x584/0x870 net/socket.c:2412 ___sys_sendmsg+0x214/0x294 net/socket.c:2466 __sys_sendmsg net/socket.c:2495 [inline] __do_sys_sendmsg net/socket.c:2504 [inline] __se_sys_sendmsg net/socket.c:2502 [inline] __arm64_sys_sendmsg+0x1ac/0x25c net/socket.c:2502 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584