Message-ID: <000000000000a7fb55061ce6cc5a@google.com>
Date: Wed, 10 Jul 2024 09:04:21 -0700
From: syzbot <syzbot+3433b5cb8b2b70933f8d@...kaller.appspotmail.com>
To: davem@...emloft.net, dsahern@...nel.org, edumazet@...gle.com, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] possible deadlock in do_ipv6_setsockopt (4)

Hello,

syzbot found the following issue on:

HEAD commit:    2f5e6395714d Merge branch 'net-pse-pd-add-new-pse-c33-feat..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16f7e781980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=db697e01efa9d1d7
dashboard link: https://syzkaller.appspot.com/bug?extid=3433b5cb8b2b70933f8d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/44296878e8d6/disk-2f5e6395.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a3f8523e4843/vmlinux-2f5e6395.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c40a60a2869f/bzImage-2f5e6395.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3433b5cb8b2b70933f8d@...kaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc6-syzkaller-01258-g2f5e6395714d #0 Not tainted
------------------------------------------------------
syz.4.1060/8537 is trying to acquire lock:
ffffffff8f5e7f48 (rtnl_mutex){+.+.}-{3:3}, at: do_ipv6_setsockopt+0x9e4/0x3630 net/ipv6/ipv6_sockglue.c:566

but task is already holding lock:
ffff88807b8c0a50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_setsockopt+0x1c3/0xe50 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}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       smc_switch_to_fallback+0x35/0xd00 net/smc/af_smc.c:902
       smc_sendmsg+0x11f/0x530 net/smc/af_smc.c:2779
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg+0x221/0x270 net/socket.c:745
       __sys_sendto+0x3a4/0x4f0 net/socket.c:2192
       __do_sys_sendto net/socket.c:2204 [inline]
       __se_sys_sendto net/socket.c:2200 [inline]
       __x64_sys_sendto+0xde/0x100 net/socket.c:2200
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       lock_sock_nested+0x48/0x100 net/core/sock.c:3543
       do_ip_setsockopt+0x1a2d/0x3cd0 net/ipv4/ip_sockglue.c:1078
       ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417
       do_sock_setsockopt+0x3af/0x720 net/socket.c:2312
       __sys_setsockopt+0x1ae/0x250 net/socket.c:2335
       __do_sys_setsockopt net/socket.c:2344 [inline]
       __se_sys_setsockopt net/socket.c:2341 [inline]
       __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2341
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (rtnl_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       do_ipv6_setsockopt+0x9e4/0x3630 net/ipv6/ipv6_sockglue.c:566
       ipv6_setsockopt+0x5c/0x1a0 net/ipv6/ipv6_sockglue.c:993
       smc_setsockopt+0x275/0xe50 net/smc/af_smc.c:3072
       do_sock_setsockopt+0x3af/0x720 net/socket.c:2312
       __sys_setsockopt+0x1ae/0x250 net/socket.c:2335
       __do_sys_setsockopt net/socket.c:2344 [inline]
       __se_sys_setsockopt net/socket.c:2341 [inline]
       __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2341
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 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_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.4.1060/8537:
 #0: ffff88807b8c0a50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_setsockopt+0x1c3/0xe50 net/smc/af_smc.c:3064

stack backtrace:
CPU: 1 PID: 8537 Comm: syz.4.1060 Not tainted 6.10.0-rc6-syzkaller-01258-g2f5e6395714d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 do_ipv6_setsockopt+0x9e4/0x3630 net/ipv6/ipv6_sockglue.c:566
 ipv6_setsockopt+0x5c/0x1a0 net/ipv6/ipv6_sockglue.c:993
 smc_setsockopt+0x275/0xe50 net/smc/af_smc.c:3072
 do_sock_setsockopt+0x3af/0x720 net/socket.c:2312
 __sys_setsockopt+0x1ae/0x250 net/socket.c:2335
 __do_sys_setsockopt net/socket.c:2344 [inline]
 __se_sys_setsockopt net/socket.c:2341 [inline]
 __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2341
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0383b75bd9
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:00007f0384934048 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f0383d03f60 RCX: 00007f0383b75bd9
RDX: 0000000000000001 RSI: 0000000000000029 RDI: 0000000000000007
RBP: 00007f0383be4aa1 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000020000080 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f0383d03f60 R15: 00007ffd8c5ba008
 </TASK>


---
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