Message-ID: <000000000000d1e06d061fb617c3@google.com>
Date: Thu, 15 Aug 2024 03:13:24 -0700
From: syzbot <syzbot+819a360379cf16b5f0d3@...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 sockopt_lock_sock

Hello,

syzbot found the following issue on:

HEAD commit:    cb2e5ee8e7a0 Merge tag 'usb-6.11-rc3' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=117b42f5980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=505ed4a1dd93463a
dashboard link: https://syzkaller.appspot.com/bug?extid=819a360379cf16b5f0d3
compiler:       gcc (Debian 12.2.0-14) 12.2.0, 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/b9161dd413ff/disk-cb2e5ee8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a97ba0acb899/vmlinux-cb2e5ee8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e959393b6d23/bzImage-cb2e5ee8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+819a360379cf16b5f0d3@...kaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc2-syzkaller-00302-gcb2e5ee8e7a0 #0 Not tainted
------------------------------------------------------
syz.0.601/6825 is trying to acquire lock:
ffff888016f53518 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1607 [inline]
ffff888016f53518 (sk_lock-AF_INET){+.+.}-{0:0}, at: sockopt_lock_sock net/core/sock.c:1061 [inline]
ffff888016f53518 (sk_lock-AF_INET){+.+.}-{0:0}, at: sockopt_lock_sock+0x54/0x70 net/core/sock.c:1052

but task is already holding lock:
ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0xf9/0x38b0 net/ipv4/ip_sockglue.c:1077

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (rtnl_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       ip_mroute_setsockopt+0x121/0x1440 net/ipv4/ipmr.c:1369
       do_ip_setsockopt+0x2e8/0x38b0 net/ipv4/ip_sockglue.c:948
       ip_setsockopt+0x59/0xf0 net/ipv4/ip_sockglue.c:1417
       udp_setsockopt+0x7d/0xd0 net/ipv4/udp.c:2806
       ipv6_setsockopt+0x175/0x1a0 net/ipv6/ipv6_sockglue.c:988
       tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:3768
       smc_setsockopt+0x1b4/0xa00 net/smc/af_smc.c:3072
       do_sock_setsockopt+0x222/0x480 net/socket.c:2324
       __sys_setsockopt+0x1a4/0x270 net/socket.c:2347
       __do_sys_setsockopt net/socket.c:2356 [inline]
       __se_sys_setsockopt net/socket.c:2353 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2353
       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 (&smc->clcsock_release_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       smc_switch_to_fallback+0x2d/0xa00 net/smc/af_smc.c:902
       smc_sendmsg+0x13d/0x520 net/smc/af_smc.c:2779
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg net/socket.c:745 [inline]
       __sys_sendto+0x47f/0x4e0 net/socket.c:2204
       __do_sys_sendto net/socket.c:2216 [inline]
       __se_sys_sendto net/socket.c:2212 [inline]
       __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2212
       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 (sk_lock-AF_INET){+.+.}-{0:0}:
       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+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
       lock_acquire kernel/locking/lockdep.c:5759 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
       lock_sock_nested+0x3a/0xf0 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+0x54/0x70 net/core/sock.c:1052
       do_ip_setsockopt+0x101/0x38b0 net/ipv4/ip_sockglue.c:1078
       ip_setsockopt+0x59/0xf0 net/ipv4/ip_sockglue.c:1417
       udp_setsockopt+0x7d/0xd0 net/ipv4/udp.c:2806
       do_sock_setsockopt+0x222/0x480 net/socket.c:2324
       __sys_setsockopt+0x1a4/0x270 net/socket.c:2347
       __do_sys_setsockopt net/socket.c:2356 [inline]
       __se_sys_setsockopt net/socket.c:2353 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2353
       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:
  sk_lock-AF_INET --> &smc->clcsock_release_lock --> rtnl_mutex

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz.0.601/6825:
 #0: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0xf9/0x38b0 net/ipv4/ip_sockglue.c:1077

stack backtrace:
CPU: 1 UID: 0 PID: 6825 Comm: syz.0.601 Not tainted 6.11.0-rc2-syzkaller-00302-gcb2e5ee8e7a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 check_noncircular+0x31a/0x400 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+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
 lock_acquire kernel/locking/lockdep.c:5759 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
 lock_sock_nested+0x3a/0xf0 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+0x54/0x70 net/core/sock.c:1052
 do_ip_setsockopt+0x101/0x38b0 net/ipv4/ip_sockglue.c:1078
 ip_setsockopt+0x59/0xf0 net/ipv4/ip_sockglue.c:1417
 udp_setsockopt+0x7d/0xd0 net/ipv4/udp.c:2806
 do_sock_setsockopt+0x222/0x480 net/socket.c:2324
 __sys_setsockopt+0x1a4/0x270 net/socket.c:2347
 __do_sys_setsockopt net/socket.c:2356 [inline]
 __se_sys_setsockopt net/socket.c:2353 [inline]
 __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2353
 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: 0033:0x7feebe5779f9
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:00007feebf2de038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007feebe706058 RCX: 00007feebe5779f9
RDX: 0000000000000030 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007feebe5e58ee R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007feebe706058 R15: 00007ffefa35bcf8
 </TASK>


---
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