syzbot

======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0 Not tainted
------------------------------------------------------
syz.4.4210/25484 is trying to acquire lock:
ffffffff8fabfb08 (
rtnl_mutex){+.+.}-{4:4}
, at: do_ipv6_setsockopt+0x1f4d/0x4660 net/ipv6/ipv6_sockglue.c:566

but task is already holding lock:
ffff8880287016a8 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x101/0xc00 net/smc/af_smc.c:3070

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&smc->clcsock_release_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       smc_switch_to_fallback+0x2d/0xa00 net/smc/af_smc.c:903
       smc_sendmsg+0x13d/0x520 net/smc/af_smc.c:2778
       sock_sendmsg_nosec net/socket.c:711 [inline]
       __sock_sendmsg net/socket.c:726 [inline]
       ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2583
       ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637
       __sys_sendmmsg+0x201/0x420 net/socket.c:2726
       __do_sys_sendmmsg net/socket.c:2753 [inline]
       __se_sys_sendmmsg net/socket.c:2750 [inline]
       __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2750
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3622
       lock_sock include/net/sock.h:1617 [inline]
       sockopt_lock_sock net/core/sock.c:1126 [inline]
       sockopt_lock_sock+0x54/0x70 net/core/sock.c:1117
       do_ipv6_setsockopt+0x1f55/0x4660 net/ipv6/ipv6_sockglue.c:567
       ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
       tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:4030
       do_sock_setsockopt+0x222/0x480 net/socket.c:2313
       __sys_setsockopt+0x1a0/0x230 net/socket.c:2338
       __do_sys_setsockopt net/socket.c:2344 [inline]
       __se_sys_setsockopt net/socket.c:2341 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2341
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (rtnl_mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain kernel/locking/lockdep.c:3904 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       do_ipv6_setsockopt+0x1f4d/0x4660 net/ipv6/ipv6_sockglue.c:566
       ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
       tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:4030
       smc_setsockopt+0x1b4/0xc00 net/smc/af_smc.c:3078
       do_sock_setsockopt+0x222/0x480 net/socket.c:2313
       __sys_setsockopt+0x1a0/0x230 net/socket.c:2338
       __do_sys_setsockopt net/socket.c:2344 [inline]
       __se_sys_setsockopt net/socket.c:2341 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2341
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  rtnl_mutex --> sk_lock-AF_INET6 --> &smc->clcsock_release_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&smc->clcsock_release_lock);
                               lock(sk_lock-AF_INET6);
                               lock(&smc->clcsock_release_lock);
  lock(rtnl_mutex);

 *** DEADLOCK ***

1 lock held by syz.4.4210/25484:
 #0: ffff8880287016a8 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x101/0xc00 net/smc/af_smc.c:3070

stack backtrace:
CPU: 0 UID: 0 PID: 25484 Comm: syz.4.4210 Not tainted 6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain kernel/locking/lockdep.c:3904 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
 do_ipv6_setsockopt+0x1f4d/0x4660 net/ipv6/ipv6_sockglue.c:566
 ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
 tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:4030
 smc_setsockopt+0x1b4/0xc00 net/smc/af_smc.c:3078
 do_sock_setsockopt+0x222/0x480 net/socket.c:2313
 __sys_setsockopt+0x1a0/0x230 net/socket.c:2338
 __do_sys_setsockopt net/socket.c:2344 [inline]
 __se_sys_setsockopt net/socket.c:2341 [inline]
 __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2341
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa7d4d85d29
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:00007fa7d5b78038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fa7d4f75fa0 RCX: 00007fa7d4d85d29
RDX: 000000000000001b RSI: 0000000000000029 RDI: 0400000000000003
RBP: 00007fa7d4e01aa8 R08: 000000000000056b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa7d4f75fa0 R15: 00007ffe5c426658
 </TASK>