syzbot


possible deadlock in sockopt_lock_sock

Status: upstream: reported C repro on 2024/08/15 10:13
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+819a360379cf16b5f0d3@syzkaller.appspotmail.com
First crash: 228d, last: 4h31m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] possible deadlock in sockopt_lock_sock 0 (2) 2024/10/09 12:50

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc2-syzkaller-00058-g75b607fab38d #0 Not tainted
------------------------------------------------------
syz-executor308/20073 is trying to acquire lock:
ffff88807c488a98 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline]
ffff88807c488a98 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sockopt_lock_sock net/core/sock.c:1125 [inline]
ffff88807c488a98 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sockopt_lock_sock+0x54/0x70 net/core/sock.c:1116

but task is already holding lock:
ffffffff8fac31e8 (rtnl_mutex){+.+.}-{3:3}, at: do_ipv6_setsockopt+0x1f4d/0x4800 net/ipv6/ipv6_sockglue.c:566

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
       do_ipv6_setsockopt+0x1f4d/0x4800 net/ipv6/ipv6_sockglue.c:566
       ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
       tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:4029
       smc_setsockopt+0x1b4/0xc00 net/smc/af_smc.c:3064
       do_sock_setsockopt+0x222/0x480 net/socket.c:2329
       __sys_setsockopt+0x1a4/0x270 net/socket.c:2352
       __do_sys_setsockopt net/socket.c:2361 [inline]
       __se_sys_setsockopt net/socket.c:2358 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2358
       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_setsockopt+0xa7b/0xc00 net/smc/af_smc.c:3087
       do_sock_setsockopt+0x222/0x480 net/socket.c:2329
       __sys_setsockopt+0x1a4/0x270 net/socket.c:2352
       __do_sys_setsockopt net/socket.c:2361 [inline]
       __se_sys_setsockopt net/socket.c:2358 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2358
       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_INET6){+.+.}-{0:0}:
       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+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3611
       lock_sock include/net/sock.h:1609 [inline]
       sockopt_lock_sock net/core/sock.c:1125 [inline]
       sockopt_lock_sock+0x54/0x70 net/core/sock.c:1116
       do_ipv6_setsockopt+0x1f55/0x4800 net/ipv6/ipv6_sockglue.c:567
       ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
       udpv6_setsockopt+0x7d/0xd0 net/ipv6/udp.c:1702
       do_sock_setsockopt+0x222/0x480 net/socket.c:2329
       __sys_setsockopt+0x1a4/0x270 net/socket.c:2352
       __do_sys_setsockopt net/socket.c:2361 [inline]
       __se_sys_setsockopt net/socket.c:2358 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2358
       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_INET6 --> &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_INET6);

 *** DEADLOCK ***

1 lock held by syz-executor308/20073:
 #0: ffffffff8fac31e8 (rtnl_mutex){+.+.}-{3:3}, at: do_ipv6_setsockopt+0x1f4d/0x4800 net/ipv6/ipv6_sockglue.c:566

stack backtrace:
CPU: 1 UID: 0 PID: 20073 Comm: syz-executor308 Not tainted 6.12.0-rc2-syzkaller-00058-g75b607fab38d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x419/0x5d0 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+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3611
 lock_sock include/net/sock.h:1609 [inline]
 sockopt_lock_sock net/core/sock.c:1125 [inline]
 sockopt_lock_sock+0x54/0x70 net/core/sock.c:1116
 do_ipv6_setsockopt+0x1f55/0x4800 net/ipv6/ipv6_sockglue.c:567
 ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
 udpv6_setsockopt+0x7d/0xd0 net/ipv6/udp.c:1702
 do_sock_setsockopt+0x222/0x480 net/socket.c:2329
 __sys_setsockopt+0x1a4/0x270 net/socket.c:2352
 __do_sys_setsockopt net/socket.c:2361 [inline]
 __se_sys_setsockopt net/socket.c:2358 [inline]
 __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2358
 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: 0033:0x7f3b71d4e8a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3b71ce7198 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f3b71dd93d8 RCX: 00007f3b71d4e8a9
RDX: 000000000000001b RSI: 0000000000000029 RDI: 0000000000000003
RBP: 00007f3b71dd93d0 R08: 000000000000056b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b71da6410
R13: 00007f3b71ce71a0 R14: 80000000000000df R15: 00007f3b71da601d
 </TASK>

Crashes (3226):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/09 12:49 upstream 75b607fab38d 56fb2cb7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/28 01:57 upstream 4fa118e5b79f 6c09fb82 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/27 11:46 upstream 1e1ba8d23dae 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/27 10:11 upstream 1e1ba8d23dae 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/27 08:27 upstream 1e1ba8d23dae 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/27 07:06 upstream 1e1ba8d23dae 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/27 05:52 upstream 1e1ba8d23dae 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/26 15:02 upstream 2df0c02dab82 19e40f48 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/26 07:08 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/26 06:07 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/26 03:52 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 23:47 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 19:21 upstream 2df0c02dab82 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 16:59 upstream 3ba7dfb8da62 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 15:18 upstream 3ba7dfb8da62 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 13:51 upstream 3ba7dfb8da62 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 11:57 upstream 3ba7dfb8da62 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 06:10 upstream 3ba7dfb8da62 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 04:03 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/25 02:01 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 22:47 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 21:19 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 18:41 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 14:35 upstream 586de92313fc 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 11:48 upstream 586de92313fc 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 08:53 upstream 586de92313fc 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 03:45 upstream 586de92313fc 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/24 01:17 upstream 586de92313fc 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/23 13:49 upstream 183601b78a9b 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/23 04:23 upstream 183601b78a9b 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/23 00:07 upstream 183601b78a9b c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/22 21:21 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/22 19:52 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/22 17:45 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/22 09:40 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/22 08:13 upstream d07de43e3f05 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/22 02:59 upstream d07de43e3f05 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 20:42 upstream d07de43e3f05 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 20:07 upstream d07de43e3f05 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 18:32 upstream b3ee1e460951 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 12:12 upstream b3ee1e460951 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 08:47 upstream b3ee1e460951 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 06:22 upstream 5fc319360819 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/21 05:09 upstream 5fc319360819 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in sockopt_lock_sock
2025/03/04 05:59 upstream 99fa936e8e4f c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root possible deadlock in sockopt_lock_sock
2025/03/02 02:08 upstream 03d38806a902 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in sockopt_lock_sock
2024/08/12 00:54 upstream cb2e5ee8e7a0 6f4edef4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root possible deadlock in sockopt_lock_sock
2025/03/09 20:19 upstream 1110ce6a1e34 163f510d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in sockopt_lock_sock
2025/03/23 06:49 upstream 183601b78a9b 4e8d3850 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in sockopt_lock_sock
2025/01/16 13:14 upstream 619f0b6fad52 968edaf4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 possible deadlock in sockopt_lock_sock
2024/08/11 10:09 upstream 5189dafa4cf9 6f4edef4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in sockopt_lock_sock
2025/01/11 11:23 git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes 6f6ecce59d99 6dbc6a9b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-riscv64 possible deadlock in sockopt_lock_sock
* Struck through repros no longer work on HEAD.