netlink: 8 bytes leftover after parsing attributes in process `syz.2.2489'.
FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.1.129-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.2489/16355 is trying to acquire lock:
ffffffff8d20a538 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:139

but task is already holding lock:
ffff8880b8f3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
       raw_spin_rq_lock kernel/sched/sched.h:1355 [inline]
       rq_lock kernel/sched/sched.h:1645 [inline]
       task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11886
       sched_cgroup_fork+0x374/0x400 kernel/sched/core.c:4684
       copy_process+0x2482/0x40a0 kernel/fork.c:2383
       kernel_clone+0x222/0x920 kernel/fork.c:2681
       user_mode_thread+0x140/0x1b0 kernel/fork.c:2757
       rest_init+0x23/0x300 init/main.c:698
       start_kernel+0x0/0x53f init/main.c:893
       start_kernel+0x496/0x53f init/main.c:1140
       secondary_startup_64_no_verify+0xcf/0xdb

-> #1 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       try_to_wake_up+0xad/0x1250 kernel/sched/core.c:4110
       up+0x6e/0x90 kernel/locking/semaphore.c:191
       __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:260
       __console_unlock kernel/printk/printk.c:2697 [inline]
       console_unlock+0x591/0x7c0 kernel/printk/printk.c:2908
       vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303
       _printk+0xd1/0x111 kernel/printk/printk.c:2328
       zstd_uncompress+0x7d1/0x7e0 fs/squashfs/zstd_wrapper.c:132
       squashfs_decompress+0xdf/0x170 fs/squashfs/decompressor_single.c:70
       squashfs_read_data+0x593/0xaf0 fs/squashfs/block.c:219
       squashfs_cache_get+0x7df/0xf70 fs/squashfs/cache.c:110
       squashfs_read_metadata+0x106/0x7d0 fs/squashfs/cache.c:344
       squashfs_read_inode+0x1f3/0x2aa0 fs/squashfs/inode.c:115
       squashfs_fill_super+0x1642/0x1d80 fs/squashfs/super.c:361
       get_tree_bdev+0x3fe/0x620 fs/super.c:1366
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3056
       do_mount fs/namespace.c:3399 [inline]
       __do_sys_mount fs/namespace.c:3607 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 ((console_sem).lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:139
       __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:243
       console_trylock kernel/printk/printk.c:2650 [inline]
       console_trylock_spinning kernel/printk/printk.c:1896 [inline]
       vprintk_emit+0x1ee/0x740 kernel/printk/printk.c:2302
       _printk+0xd1/0x111 kernel/printk/printk.c:2328
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147
       strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
       ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline]
       bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
       bpf_prog_bc7c5c6b9645592f+0x35/0x37
       bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline]
       __bpf_prog_run include/linux/filter.h:603 [inline]
       bpf_prog_run include/linux/filter.h:610 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
       bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
       __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x2128/0x4570 kernel/sched/core.c:6557
       preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6729
       preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6753
       preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
       vprintk_emit+0x683/0x740 kernel/printk/printk.c:2304
       _printk+0xd1/0x111 kernel/printk/printk.c:2328
       __nla_validate_parse+0x2307/0x2c30 lib/nlattr.c:619
       __nla_parse+0x3c/0x50 lib/nlattr.c:704
       __nlmsg_parse include/net/netlink.h:748 [inline]
       genl_family_rcv_msg_attrs_parse+0x1d1/0x290 net/netlink/genetlink.c:565
       genl_family_rcv_msg_doit net/netlink/genetlink.c:734 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
       genl_rcv_msg+0x829/0xf50 net/netlink/genetlink.c:850
       netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2493
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
       netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
       netlink_unicast+0x7e2/0x970 net/netlink/af_netlink.c:1337
       netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1859
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x5d3/0x9a0 net/socket.c:2519
       ___sys_sendmsg net/socket.c:2573 [inline]
       __sys_sendmsg+0x2a9/0x390 net/socket.c:2602
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  (console_sem).lock --> &p->pi_lock --> &rq->__lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rq->__lock);
                               lock(&p->pi_lock);
                               lock(&rq->__lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

4 locks held by syz.2.2489/16355:
 #0: ffffffff8e5b09f0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:860
 #1: ffffffff8e5b08a8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8e5b08a8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x125/0xf50 net/netlink/genetlink.c:848
 #2: ffff8880b8f3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #3: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #3: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #3: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
 #3: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2325

stack backtrace:
CPU: 1 PID: 16355 Comm: syz.2.2489 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
 down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:139
 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:243
 console_trylock kernel/printk/printk.c:2650 [inline]
 console_trylock_spinning kernel/printk/printk.c:1896 [inline]
 vprintk_emit+0x1ee/0x740 kernel/printk/printk.c:2302
 _printk+0xd1/0x111 kernel/printk/printk.c:2328
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147
 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
 ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline]
 bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
 bpf_prog_bc7c5c6b9645592f+0x35/0x37
 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x2128/0x4570 kernel/sched/core.c:6557
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6729
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6753
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 vprintk_emit+0x683/0x740 kernel/printk/printk.c:2304
 _printk+0xd1/0x111 kernel/printk/printk.c:2328
 __nla_validate_parse+0x2307/0x2c30 lib/nlattr.c:619
 __nla_parse+0x3c/0x50 lib/nlattr.c:704
 __nlmsg_parse include/net/netlink.h:748 [inline]
 genl_family_rcv_msg_attrs_parse+0x1d1/0x290 net/netlink/genetlink.c:565
 genl_family_rcv_msg_doit net/netlink/genetlink.c:734 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
 genl_rcv_msg+0x829/0xf50 net/netlink/genetlink.c:850
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2493
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x7e2/0x970 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1859
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5d3/0x9a0 net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2602
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efd67f8d169
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efd68e8f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007efd681a5fa0 RCX: 00007efd67f8d169
RDX: 0000000000004000 RSI: 0000400000000100 RDI: 0000000000000003
RBP: 00007efd68e8f090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007efd681a5fa0 R15: 00007ffcbef16588
 </TASK>
CPU: 1 PID: 16355 Comm: syz.2.2489 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail_ex+0x3a6/0x4d0 lib/fault-inject.c:147
 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
 ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline]
 bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
 bpf_prog_bc7c5c6b9645592f+0x35/0x37
 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x2128/0x4570 kernel/sched/core.c:6557
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6729
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6753
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 vprintk_emit+0x683/0x740 kernel/printk/printk.c:2304
 _printk+0xd1/0x111 kernel/printk/printk.c:2328
 __nla_validate_parse+0x2307/0x2c30 lib/nlattr.c:619
 __nla_parse+0x3c/0x50 lib/nlattr.c:704
 __nlmsg_parse include/net/netlink.h:748 [inline]
 genl_family_rcv_msg_attrs_parse+0x1d1/0x290 net/netlink/genetlink.c:565
 genl_family_rcv_msg_doit net/netlink/genetlink.c:734 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
 genl_rcv_msg+0x829/0xf50 net/netlink/genetlink.c:850
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2493
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x7e2/0x970 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1859
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5d3/0x9a0 net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2602
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efd67f8d169
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efd68e8f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007efd681a5fa0 RCX: 00007efd67f8d169
RDX: 0000000000004000 RSI: 0000400000000100 RDI: 0000000000000003
RBP: 00007efd68e8f090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007efd681a5fa0 R15: 00007ffcbef16588
 </TASK>