[syzbot] [net?] possible deadlock in rtnl_lock (8)

[syzbot <syzbot+51cf7cc5f9ffc1006ef2@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    1fb918967b56 Merge tag 'for-6.11-rc3-tag' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=129dd7d9980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=804764788c03071f
dashboard link: https://syzkaller.appspot.com/bug?extid=51cf7cc5f9ffc1006ef2
compiler:       aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-1fb91896.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7b8fac7b5b8b/vmlinux-1fb91896.xz
kernel image: https://storage.googleapis.com/syzbot-assets/676950a147e6/Image-1fb91896.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+51cf7cc5f9ffc1006ef2@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc3-syzkaller-00066-g1fb918967b56 #0 Not tainted
------------------------------------------------------
syz.0.5481/17612 is trying to acquire lock:
ffff8000880033a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x1c/0x28 net/core/rtnetlink.c:79

but task is already holding lock:
ffff000010332b50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_setsockopt+0xd8/0xcec net/smc/af_smc.c:3064

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&smc->clcsock_release_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x134/0x840 kernel/locking/mutex.c:752
       mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:804
       smc_switch_to_fallback+0x34/0x80c net/smc/af_smc.c:902
       smc_sendmsg+0xe4/0x8f8 net/smc/af_smc.c:2779
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg+0xc8/0x168 net/socket.c:745
       __sys_sendto+0x1a8/0x254 net/socket.c:2204
       __do_sys_sendto net/socket.c:2216 [inline]
       __se_sys_sendto net/socket.c:2212 [inline]
       __arm64_sys_sendto+0xc0/0x134 net/socket.c:2212
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
       el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x50/0x180 arch/arm64/kernel/entry-common.c:712
       el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
       el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

-> #1 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_sock_nested+0x38/0xe8 net/core/sock.c:3543
       lock_sock include/net/sock.h:1607 [inline]
       sockopt_lock_sock net/core/sock.c:1061 [inline]
       sockopt_lock_sock+0x58/0x74 net/core/sock.c:1052
       do_ip_setsockopt+0xe0/0x2358 net/ipv4/ip_sockglue.c:1078
       ip_setsockopt+0x34/0x9c net/ipv4/ip_sockglue.c:1417
       raw_setsockopt+0x7c/0x2e0 net/ipv4/raw.c:845
       sock_common_setsockopt+0x70/0xe0 net/core/sock.c:3735
       do_sock_setsockopt+0x17c/0x354 net/socket.c:2324
       __sys_setsockopt+0xdc/0x178 net/socket.c:2347
       __do_sys_setsockopt net/socket.c:2356 [inline]
       __se_sys_setsockopt net/socket.c:2353 [inline]
       __arm64_sys_setsockopt+0xa4/0x100 net/socket.c:2353
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
       el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x50/0x180 arch/arm64/kernel/entry-common.c:712
       el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
       el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

-> #0 (rtnl_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3133 [inline]
       check_prevs_add kernel/locking/lockdep.c:3252 [inline]
       validate_chain kernel/locking/lockdep.c:3868 [inline]
       __lock_acquire+0x2aa4/0x6340 kernel/locking/lockdep.c:5142
       lock_acquire kernel/locking/lockdep.c:5759 [inline]
       lock_acquire+0x48c/0x7a4 kernel/locking/lockdep.c:5724
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x134/0x840 kernel/locking/mutex.c:752
       mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:804
       rtnl_lock+0x1c/0x28 net/core/rtnetlink.c:79
       do_ipv6_setsockopt+0x1a04/0x3814 net/ipv6/ipv6_sockglue.c:566
       ipv6_setsockopt+0xc8/0x140 net/ipv6/ipv6_sockglue.c:993
       tcp_setsockopt+0x90/0xcc net/ipv4/tcp.c:3768
       sock_common_setsockopt+0x70/0xe0 net/core/sock.c:3735
       smc_setsockopt+0x150/0xcec net/smc/af_smc.c:3072
       do_sock_setsockopt+0x17c/0x354 net/socket.c:2324
       __sys_setsockopt+0xdc/0x178 net/socket.c:2347
       __do_sys_setsockopt net/socket.c:2356 [inline]
       __se_sys_setsockopt net/socket.c:2353 [inline]
       __arm64_sys_setsockopt+0xa4/0x100 net/socket.c:2353
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
       el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x50/0x180 arch/arm64/kernel/entry-common.c:712
       el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
       el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz.0.5481/17612:
 #0: ffff000010332b50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_setsockopt+0xd8/0xcec net/smc/af_smc.c:3064

stack backtrace:
CPU: 1 UID: 0 PID: 17612 Comm: syz.0.5481 Not tainted 6.11.0-rc3-syzkaller-00066-g1fb918967b56 #0
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x9c/0x11c arch/arm64/kernel/stacktrace.c:317
 show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:324
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0xa4/0xf4 lib/dump_stack.c:119
 dump_stack+0x1c/0x28 lib/dump_stack.c:128
 print_circular_bug+0x420/0x6f8 kernel/locking/lockdep.c:2059
 check_noncircular+0x2dc/0x364 kernel/locking/lockdep.c:2186
 check_prev_add kernel/locking/lockdep.c:3133 [inline]
 check_prevs_add kernel/locking/lockdep.c:3252 [inline]
 validate_chain kernel/locking/lockdep.c:3868 [inline]
 __lock_acquire+0x2aa4/0x6340 kernel/locking/lockdep.c:5142
 lock_acquire kernel/locking/lockdep.c:5759 [inline]
 lock_acquire+0x48c/0x7a4 kernel/locking/lockdep.c:5724
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x134/0x840 kernel/locking/mutex.c:752
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:804
 rtnl_lock+0x1c/0x28 net/core/rtnetlink.c:79
 do_ipv6_setsockopt+0x1a04/0x3814 net/ipv6/ipv6_sockglue.c:566
 ipv6_setsockopt+0xc8/0x140 net/ipv6/ipv6_sockglue.c:993
 tcp_setsockopt+0x90/0xcc net/ipv4/tcp.c:3768
 sock_common_setsockopt+0x70/0xe0 net/core/sock.c:3735
 smc_setsockopt+0x150/0xcec net/smc/af_smc.c:3072
 do_sock_setsockopt+0x17c/0x354 net/socket.c:2324
 __sys_setsockopt+0xdc/0x178 net/socket.c:2347
 __do_sys_setsockopt net/socket.c:2356 [inline]
 __se_sys_setsockopt net/socket.c:2353 [inline]
 __arm64_sys_setsockopt+0xa4/0x100 net/socket.c:2353
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x50/0x180 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598


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