[syzbot] possible deadlock in l2tp_tunnel_register

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 064bc7312bd0 netdevsim: Fix memory leak of nsim_dev->fa_co..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=16948779880000
kernel config: https://syzkaller.appspot.com/x/.config?x=a33ac7bbc22a8c35
dashboard link: https://syzkaller.appspot.com/bug?extid=de987172bb74a381879b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0634e1c0e4cb/disk-064bc731.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe1039d2de22/vmlinux-064bc731.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a0d673875fa/bzImage-064bc731.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+de9871...@syzkaller.appspotmail.com

========================================================
WARNING: possible irq lock inversion dependency detected
6.1.0-rc4-syzkaller-00212-g064bc7312bd0 #0 Not tainted
--------------------------------------------------------
syz-executor.0/4763 just changed the state of lock:
ffff8880785323b8 (clock-AF_INET6){+++.}-{2:2}, at: l2tp_tunnel_register+0x126/0x1210 net/l2tp/l2tp_core.c:1477
but this lock was taken by another, SOFTIRQ-safe lock in the past:
(&tcp_hashinfo.bhash[i].lock){+.-.}-{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(clock-AF_INET6);
local_irq_disable();
lock(&tcp_hashinfo.bhash[i].lock);
lock(clock-AF_INET6);
<Interrupt>
lock(&tcp_hashinfo.bhash[i].lock);

*** DEADLOCK ***

1 lock held by syz-executor.0/4763:
#0: ffff88807d11e130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1721 [inline]
#0: ffff88807d11e130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0xadc/0x1a10 net/l2tp/l2tp_ppp.c:675

the shortest dependencies between 2nd lock and 1st lock:
-> (&tcp_hashinfo.bhash[i].lock){+.-.}-{2:2} {
HARDIRQ-ON-W at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
inet_csk_get_port+0x66a/0x2640 net/ipv4/inet_connection_sock.c:496
__inet6_bind+0x625/0x1b20 net/ipv6/af_inet6.c:412
inet6_bind+0x177/0x220 net/ipv6/af_inet6.c:471
rds_tcp_listen_init+0x2a9/0x4e0 net/rds/tcp_listen.c:307
rds_tcp_init_net+0x21d/0x4f0 net/rds/tcp.c:573
ops_init+0xb9/0x680 net/core/net_namespace.c:135
__register_pernet_operations net/core/net_namespace.c:1153 [inline]
register_pernet_operations+0x35a/0x850 net/core/net_namespace.c:1222
register_pernet_device+0x2a/0x80 net/core/net_namespace.c:1309
rds_tcp_init+0x65/0xd3 net/rds/tcp.c:731
do_one_initcall+0x141/0x780 init/main.c:1303
do_initcall_level init/main.c:1376 [inline]
do_initcalls init/main.c:1392 [inline]
do_basic_setup init/main.c:1411 [inline]
kernel_init_freeable+0x6ff/0x788 init/main.c:1631
kernel_init+0x1e/0x1d0 init/main.c:1519
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
IN-SOFTIRQ-W at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:350 [inline]
__inet_inherit_port+0x297/0x14e0 net/ipv4/inet_hashtables.c:229
tcp_v4_syn_recv_sock+0xb5b/0x14c0 net/ipv4/tcp_ipv4.c:1588
tcp_check_req+0x632/0x1aa0 net/ipv4/tcp_minisocks.c:786
tcp_v4_rcv+0x24b4/0x3980 net/ipv4/tcp_ipv4.c:2030
ip_protocol_deliver_rcu+0x9f/0x7c0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x2ec/0x4c0 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:302 [inline]
NF_HOOK include/linux/netfilter.h:296 [inline]
ip_local_deliver+0x1ae/0x200 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:455 [inline]
ip_sublist_rcv_finish+0x9a/0x2c0 net/ipv4/ip_input.c:575
ip_list_rcv_finish net/ipv4/ip_input.c:625 [inline]
ip_sublist_rcv+0x533/0x980 net/ipv4/ip_input.c:633
ip_list_rcv+0x31e/0x470 net/ipv4/ip_input.c:668
__netif_receive_skb_list_ptype net/core/dev.c:5532 [inline]
__netif_receive_skb_list_core+0x548/0x8f0 net/core/dev.c:5580
__netif_receive_skb_list net/core/dev.c:5632 [inline]
netif_receive_skb_list_internal+0x75f/0xd90 net/core/dev.c:5723
gro_normal_list include/net/gro.h:433 [inline]
gro_normal_list include/net/gro.h:429 [inline]
napi_complete_done+0x1f5/0x890 net/core/dev.c:6064
virtqueue_napi_complete drivers/net/virtio_net.c:401 [inline]
virtnet_poll+0xd08/0x1300 drivers/net/virtio_net.c:1678
__napi_poll+0xb8/0x770 net/core/dev.c:6498
napi_poll net/core/dev.c:6565 [inline]
net_rx_action+0xa00/0xde0 net/core/dev.c:6676
__do_softirq+0x1fb/0xadc kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
common_interrupt+0xad/0xd0 arch/x86/kernel/irq.c:240
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:640
native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
acpi_idle_do_entry+0x1fd/0x2a0 drivers/acpi/processor_idle.c:572
acpi_idle_enter+0x368/0x510 drivers/acpi/processor_idle.c:709
cpuidle_enter_state+0x1af/0xd40 drivers/cpuidle/cpuidle.c:239
cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:356
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:236 [inline]
do_idle+0x3f7/0x590 kernel/sched/idle.c:303
cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:400
start_secondary+0x256/0x300 arch/x86/kernel/smpboot.c:262
secondary_startup_64_no_verify+0xce/0xdb
INITIAL USE at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
inet_csk_get_port+0x66a/0x2640 net/ipv4/inet_connection_sock.c:496
__inet6_bind+0x625/0x1b20 net/ipv6/af_inet6.c:412
inet6_bind+0x177/0x220 net/ipv6/af_inet6.c:471
rds_tcp_listen_init+0x2a9/0x4e0 net/rds/tcp_listen.c:307
rds_tcp_init_net+0x21d/0x4f0 net/rds/tcp.c:573
ops_init+0xb9/0x680 net/core/net_namespace.c:135
__register_pernet_operations net/core/net_namespace.c:1153 [inline]
register_pernet_operations+0x35a/0x850 net/core/net_namespace.c:1222
register_pernet_device+0x2a/0x80 net/core/net_namespace.c:1309
rds_tcp_init+0x65/0xd3 net/rds/tcp.c:731
do_one_initcall+0x141/0x780 init/main.c:1303
do_initcall_level init/main.c:1376 [inline]
do_initcalls init/main.c:1392 [inline]
do_basic_setup init/main.c:1411 [inline]
kernel_init_freeable+0x6ff/0x788 init/main.c:1631
kernel_init+0x1e/0x1d0 init/main.c:1519
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
}
... key at: [<ffffffff91d7c600>] __key.1+0x0/0x40
... acquired at:
__raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline]
_raw_read_lock_bh+0x3f/0x70 kernel/locking/spinlock.c:252
sock_i_uid+0x1f/0xb0 net/core/sock.c:2542
sk_reuseport_match net/ipv4/inet_connection_sock.c:383 [inline]
inet_csk_get_port+0x869/0x2640 net/ipv4/inet_connection_sock.c:514
__inet6_bind+0x625/0x1b20 net/ipv6/af_inet6.c:412
inet6_bind+0x177/0x220 net/ipv6/af_inet6.c:471
__sys_bind+0x1ed/0x260 net/socket.c:1776
__do_sys_bind net/socket.c:1787 [inline]
__se_sys_bind net/socket.c:1785 [inline]
__x64_sys_bind+0x73/0xb0 net/socket.c:1785
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> (clock-AF_INET6){+++.}-{2:2} {
HARDIRQ-ON-W at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline]
_raw_write_lock_bh+0x33/0x40 kernel/locking/spinlock.c:334
sock_orphan include/net/sock.h:2090 [inline]
sk_common_release+0xc6/0x390 net/core/sock.c:3672
inet_release+0x132/0x270 net/ipv4/af_inet.c:428
inet6_release+0x50/0x70 net/ipv6/af_inet6.c:488
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x1c/0x20 net/socket.c:1365
__fput+0x27c/0xa90 fs/file_table.c:320
task_work_run+0x16f/0x270 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
HARDIRQ-ON-R at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline]
_raw_read_lock_bh+0x3f/0x70 kernel/locking/spinlock.c:252
sock_i_uid+0x1f/0xb0 net/core/sock.c:2542
udp_lib_lport_inuse+0x32/0x490 net/ipv4/udp.c:140
udp_lib_get_port+0x835/0x18c0 net/ipv4/udp.c:306
__inet6_bind+0x625/0x1b20 net/ipv6/af_inet6.c:412
inet6_bind+0x177/0x220 net/ipv6/af_inet6.c:471
__sys_bind+0x1ed/0x260 net/socket.c:1776
__do_sys_bind net/socket.c:1787 [inline]
__se_sys_bind net/socket.c:1785 [inline]
__x64_sys_bind+0x73/0xb0 net/socket.c:1785
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
SOFTIRQ-ON-W at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
_raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300
l2tp_tunnel_register+0x126/0x1210 net/l2tp/l2tp_core.c:1477
pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
__sys_connect_file+0x153/0x1a0 net/socket.c:1976
__sys_connect+0x165/0x1a0 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x73/0xb0 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
INITIAL USE at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline]
_raw_write_lock_bh+0x33/0x40 kernel/locking/spinlock.c:334
sock_orphan include/net/sock.h:2090 [inline]
sk_common_release+0xc6/0x390 net/core/sock.c:3672
inet_release+0x132/0x270 net/ipv4/af_inet.c:428
inet6_release+0x50/0x70 net/ipv6/af_inet6.c:488
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x1c/0x20 net/socket.c:1365
__fput+0x27c/0xa90 fs/file_table.c:320
task_work_run+0x16f/0x270 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
INITIAL READ USE at:
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline]
_raw_read_lock_bh+0x3f/0x70 kernel/locking/spinlock.c:252
sock_i_uid+0x1f/0xb0 net/core/sock.c:2542
udp_lib_lport_inuse+0x32/0x490 net/ipv4/udp.c:140
udp_lib_get_port+0x835/0x18c0 net/ipv4/udp.c:306
__inet6_bind+0x625/0x1b20 net/ipv6/af_inet6.c:412
inet6_bind+0x177/0x220 net/ipv6/af_inet6.c:471
__sys_bind+0x1ed/0x260 net/socket.c:1776
__do_sys_bind net/socket.c:1787 [inline]
__se_sys_bind net/socket.c:1785 [inline]
__x64_sys_bind+0x73/0xb0 net/socket.c:1785
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
}
... key at: [<ffffffff91d5caa0>] af_callback_keys+0xa0/0x300
... acquired at:
mark_lock kernel/locking/lockdep.c:4598 [inline]
mark_usage kernel/locking/lockdep.c:4547 [inline]
__lock_acquire+0x893/0x56d0 kernel/locking/lockdep.c:5009
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
_raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300
l2tp_tunnel_register+0x126/0x1210 net/l2tp/l2tp_core.c:1477
pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
__sys_connect_file+0x153/0x1a0 net/socket.c:1976
__sys_connect+0x165/0x1a0 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x73/0xb0 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd


stack backtrace:
CPU: 1 PID: 4763 Comm: syz-executor.0 Not tainted 6.1.0-rc4-syzkaller-00212-g064bc7312bd0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
print_irq_inversion_bug kernel/locking/lockdep.c:222 [inline]
check_usage_backwards kernel/locking/lockdep.c:4105 [inline]
mark_lock_irq kernel/locking/lockdep.c:4198 [inline]
mark_lock.part.0.cold+0x61/0xd8 kernel/locking/lockdep.c:4634
mark_lock kernel/locking/lockdep.c:4598 [inline]
mark_usage kernel/locking/lockdep.c:4547 [inline]
__lock_acquire+0x893/0x56d0 kernel/locking/lockdep.c:5009
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
_raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300
l2tp_tunnel_register+0x126/0x1210 net/l2tp/l2tp_core.c:1477
pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
__sys_connect_file+0x153/0x1a0 net/socket.c:1976
__sys_connect+0x165/0x1a0 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x73/0xb0 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6ed8e8b639
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6ed9c29168 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f6ed8fabf80 RCX: 00007f6ed8e8b639
RDX: 000000000000002e RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007f6ed8ee6ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc86db2b3f R14: 00007f6ed9c29300 R15: 0000000000022000
</TASK>
BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:49
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4763, name: syz-executor.0
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 PID: 4763 Comm: syz-executor.0 Not tainted 6.1.0-rc4-syzkaller-00212-g064bc7312bd0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
__might_resched.cold+0x222/0x26b kernel/sched/core.c:9890
percpu_down_read include/linux/percpu-rwsem.h:49 [inline]
cpus_read_lock+0x1b/0x140 kernel/cpu.c:310
static_key_slow_inc+0x12/0x20 kernel/jump_label.c:158
udp_tunnel_encap_enable include/net/udp_tunnel.h:187 [inline]
setup_udp_tunnel_sock+0x43d/0x550 net/ipv4/udp_tunnel_core.c:81
l2tp_tunnel_register+0xc51/0x1210 net/l2tp/l2tp_core.c:1509
pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
__sys_connect_file+0x153/0x1a0 net/socket.c:1976
__sys_connect+0x165/0x1a0 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x73/0xb0 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6ed8e8b639
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6ed9c29168 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f6ed8fabf80 RCX: 00007f6ed8e8b639
RDX: 000000000000002e RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007f6ed8ee6ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc86db2b3f R14: 00007f6ed9c29300 R15: 0000000000022000
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 064bc7312bd0 netdevsim: Fix memory leak of nsim_dev->fa_co..
git tree: net

console+strace: https://syzkaller.appspot.com/x/log.txt?x=10c43901880000

kernel config: https://syzkaller.appspot.com/x/.config?x=a33ac7bbc22a8c35
dashboard link: https://syzkaller.appspot.com/bug?extid=de987172bb74a381879b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c1efc1880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=128d2759880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0634e1c0e4cb/disk-064bc731.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe1039d2de22/vmlinux-064bc731.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a0d673875fa/bzImage-064bc731.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+de9871...@syzkaller.appspotmail.com

========================================================
WARNING: possible irq lock inversion dependency detected
6.1.0-rc4-syzkaller-00212-g064bc7312bd0 #0 Not tainted
--------------------------------------------------------

syz-executor187/3642 just changed the state of lock:
ffff88814c00c3b8 (clock-AF_INET6){+++.}-{2:2}, at: l2tp_tunnel_register+0x126/0x1210 net/l2tp/l2tp_core.c:1477

but this lock was taken by another, SOFTIRQ-safe lock in the past:
(&tcp_hashinfo.bhash[i].lock){+.-.}-{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(clock-AF_INET6);
local_irq_disable();
lock(&tcp_hashinfo.bhash[i].lock);
lock(clock-AF_INET6);
<Interrupt>
lock(&tcp_hashinfo.bhash[i].lock);

*** DEADLOCK ***

1 lock held by syz-executor187/3642:
#0: ffff8881479e1130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1721 [inline]
#0: ffff8881479e1130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0xadc/0x1a10 net/l2tp/l2tp_ppp.c:675

rest_init+0x16d/0x270 init/main.c:729
arch_call_rest_init+0x13/0x1c init/main.c:890
start_kernel+0x477/0x498 init/main.c:1145

CPU: 1 PID: 3642 Comm: syz-executor187 Not tainted 6.1.0-rc4-syzkaller-00212-g064bc7312bd0 #0

RIP: 0033:0x7f871cf84b99
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:00007fff53ae7948 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f871cf84b99

RDX: 000000000000002e RSI: 0000000020000000 RDI: 0000000000000003

RBP: 00007f871cf48d40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f871cf48dd0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

</TASK>
BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:49

in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 3642, name: syz-executor187

preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0

CPU: 1 PID: 3642 Comm: syz-executor187 Not tainted 6.1.0-rc4-syzkaller-00212-g064bc7312bd0 #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
__might_resched.cold+0x222/0x26b kernel/sched/core.c:9890
percpu_down_read include/linux/percpu-rwsem.h:49 [inline]
cpus_read_lock+0x1b/0x140 kernel/cpu.c:310
static_key_slow_inc+0x12/0x20 kernel/jump_label.c:158
udp_tunnel_encap_enable include/net/udp_tunnel.h:187 [inline]
setup_udp_tunnel_sock+0x43d/0x550 net/ipv4/udp_tunnel_core.c:81
l2tp_tunnel_register+0xc51/0x1210 net/l2tp/l2tp_core.c:1509
pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
__sys_connect_file+0x153/0x1a0 net/socket.c:1976
__sys_connect+0x165/0x1a0 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x73/0xb0 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f871cf84b99
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