syzbot


possible deadlock in do_ip_getsockopt (3)

Status: upstream: reported on 2024/07/10 21:17
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+aa5e39930997b0fe3dba@syzkaller.appspotmail.com
First crash: 7d02h, last: 7d02h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] possible deadlock in do_ip_getsockopt (3) 0 (1) 2024/07/10 21:17
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in do_ip_getsockopt netfilter 22 2353d 2358d 4/27 fixed on 2018/02/04 23:45
android-49 possible deadlock in do_ip_getsockopt 4 2200d 2236d 0/3 auto-closed as invalid on 2019/02/22 14:29
upstream possible deadlock in do_ip_getsockopt (2) netfilter 206 2331d 2346d 4/27 fixed on 2018/02/26 20:04

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc6-next-20240703-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.2164/18168 is trying to acquire lock:
ffffffff8f5ff788 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_getsockopt+0x10f5/0x2940 net/ipv4/ip_sockglue.c:1702

but task is already holding lock:
ffff88807ce84c50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_getsockopt+0x144/0x3e0 net/smc/af_smc.c:3144

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:5816
       __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:2204
       __do_sys_sendto net/socket.c:2216 [inline]
       __se_sys_sendto net/socket.c:2212 [inline]
       __x64_sys_sendto+0xde/0x100 net/socket.c:2212
       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:5816
       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:2324
       __sys_setsockopt+0x1ae/0x250 net/socket.c:2347
       __do_sys_setsockopt net/socket.c:2356 [inline]
       __se_sys_setsockopt net/socket.c:2353 [inline]
       __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2353
       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:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1359/0x2000 kernel/locking/lockdep.c:5193
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5816
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       do_ip_getsockopt+0x10f5/0x2940 net/ipv4/ip_sockglue.c:1702
       ip_getsockopt+0xed/0x2e0 net/ipv4/ip_sockglue.c:1765
       tcp_getsockopt+0x163/0x1c0 net/ipv4/tcp.c:4409
       smc_getsockopt+0x1d9/0x3e0 net/smc/af_smc.c:3154
       do_sock_getsockopt+0x373/0x850 net/socket.c:2386
       __sys_getsockopt+0x271/0x330 net/socket.c:2415
       __do_sys_getsockopt net/socket.c:2425 [inline]
       __se_sys_getsockopt net/socket.c:2422 [inline]
       __x64_sys_getsockopt+0xb5/0xd0 net/socket.c:2422
       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.4.2164/18168:
 #0: ffff88807ce84c50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_getsockopt+0x144/0x3e0 net/smc/af_smc.c:3144

stack backtrace:
CPU: 0 UID: 0 PID: 18168 Comm: syz.4.2164 Not tainted 6.10.0-rc6-next-20240703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1359/0x2000 kernel/locking/lockdep.c:5193
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5816
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 do_ip_getsockopt+0x10f5/0x2940 net/ipv4/ip_sockglue.c:1702
 ip_getsockopt+0xed/0x2e0 net/ipv4/ip_sockglue.c:1765
 tcp_getsockopt+0x163/0x1c0 net/ipv4/tcp.c:4409
 smc_getsockopt+0x1d9/0x3e0 net/smc/af_smc.c:3154
 do_sock_getsockopt+0x373/0x850 net/socket.c:2386
 __sys_getsockopt+0x271/0x330 net/socket.c:2415
 __do_sys_getsockopt net/socket.c:2425 [inline]
 __se_sys_getsockopt net/socket.c:2422 [inline]
 __x64_sys_getsockopt+0xb5/0xd0 net/socket.c:2422
 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: 0033:0x7fa7f3175bd9
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:00007fa7f2bff048 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007fa7f3303f60 RCX: 00007fa7f3175bd9
RDX: 0000000000000029 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007fa7f31e4aa1 R08: 00000000200000c0 R09: 0000000000000000
R10: 0000000020000080 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa7f3303f60 R15: 00007fffb5a9a058
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/07/06 21:07 linux-next 0b58e108042b bc4ebbb5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in do_ip_getsockopt
* Struck through repros no longer work on HEAD.