syzbot


possible deadlock in smc_pnet_find_ism_resource

Status: upstream: reported C repro on 2025/01/19 00:44
Subsystems: s390 net
[Documentation on labels]
Reported-by: syzbot+f160105b2817964a0886@syzkaller.appspotmail.com
First crash: 5d22h, last: 5d19h
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [s390?] [net?] possible deadlock in smc_pnet_find_ism_resource 0 (1) 2025/01/19 00:44

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc6-syzkaller-00147-g665bcfc982de #0 Not tainted
------------------------------------------------------
syz-executor304/5836 is trying to acquire lock:
ffffffff8fcb2dc8 (rtnl_mutex){+.+.}-{4:4}, at: pnet_find_base_ndev net/smc/smc_pnet.c:945 [inline]
ffffffff8fcb2dc8 (rtnl_mutex){+.+.}-{4:4}, at: smc_pnet_find_ism_by_pnetid net/smc/smc_pnet.c:1101 [inline]
ffffffff8fcb2dc8 (rtnl_mutex){+.+.}-{4:4}, at: smc_pnet_find_ism_resource+0xe1/0x510 net/smc/smc_pnet.c:1152

but task is already holding lock:
ffff888077140258 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1623 [inline]
ffff888077140258 (sk_lock-AF_INET){+.+.}-{0:0}, at: smc_connect+0xb7/0xde0 net/smc/af_smc.c:1641

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       lock_sock_nested+0x48/0x100 net/core/sock.c:3625
       do_ip_setsockopt+0x1a2d/0x3cd0 net/ipv4/ip_sockglue.c:1078
       ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417
       dccp_setsockopt+0x17c/0x12c0 net/dccp/proto.c:579
       do_sock_setsockopt+0x3af/0x720 net/socket.c:2313
       __sys_setsockopt net/socket.c:2338 [inline]
       __do_sys_setsockopt net/socket.c:2344 [inline]
       __se_sys_setsockopt net/socket.c:2341 [inline]
       __x64_sys_setsockopt+0x1ee/0x280 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){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       pnet_find_base_ndev net/smc/smc_pnet.c:945 [inline]
       smc_pnet_find_ism_by_pnetid net/smc/smc_pnet.c:1101 [inline]
       smc_pnet_find_ism_resource+0xe1/0x510 net/smc/smc_pnet.c:1152
       smc_find_ism_device net/smc/af_smc.c:1011 [inline]
       smc_find_proposal_devices net/smc/af_smc.c:1096 [inline]
       __smc_connect+0x390/0x1850 net/smc/af_smc.c:1523
       smc_connect+0x868/0xde0 net/smc/af_smc.c:1693
       __sys_connect_file net/socket.c:2055 [inline]
       __sys_connect+0x288/0x2d0 net/socket.c:2074
       __do_sys_connect net/socket.c:2080 [inline]
       __se_sys_connect net/socket.c:2077 [inline]
       __x64_sys_connect+0x7a/0x90 net/socket.c:2077
       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:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sk_lock-AF_INET);
                               lock(rtnl_mutex);
                               lock(sk_lock-AF_INET);
  lock(rtnl_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor304/5836:
 #0: ffff888077140258 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1623 [inline]
 #0: ffff888077140258 (sk_lock-AF_INET){+.+.}-{0:0}, at: smc_connect+0xb7/0xde0 net/smc/af_smc.c:1641

stack backtrace:
CPU: 1 UID: 0 PID: 5836 Comm: syz-executor304 Not tainted 6.13.0-rc6-syzkaller-00147-g665bcfc982de #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+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:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
 pnet_find_base_ndev net/smc/smc_pnet.c:945 [inline]
 smc_pnet_find_ism_by_pnetid net/smc/smc_pnet.c:1101 [inline]
 smc_pnet_find_ism_resource+0xe1/0x510 net/smc/smc_pnet.c:1152
 smc_find_ism_device net/smc/af_smc.c:1011 [inline]
 smc_find_proposal_devices net/smc/af_smc.c:1096 [inline]
 __smc_connect+0x390/0x1850 net/smc/af_smc.c:1523
 smc_connect+0x868/0xde0 net/smc/af_smc.c:1693
 __sys_connect_file net/socket.c:2055 [inline]
 __sys_connect+0x288/0x2d0 net/socket.c:2074
 __do_sys_connect net/socket.c:2080 [inline]
 __se_sys_connect net/socket.c:2077 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2077
 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: 0033:0x7f00e4558799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff72e40d38 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f00e45a5490 RCX: 00007f00e4558799
RDX: 0000000000000010 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00007f00e45a5460 R08: 0000555500000000 R09: 0000555500000000
R10: 0000000000000010 R11: 0000000000000246 R12: 00007f00e45a53e5
R13: 0000000000000001 R14: 00007fff72e40d80 R15: 0000000000000003
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/15 03:26 net 665bcfc982de 7315a7cf .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in smc_pnet_find_ism_resource
2025/01/15 01:48 net 665bcfc982de 7315a7cf .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in smc_pnet_find_ism_resource
2025/01/15 00:40 net 665bcfc982de 7315a7cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in smc_pnet_find_ism_resource
* Struck through repros no longer work on HEAD.