[syzbot] [net?] possible deadlock in ip_mroute_setsockopt

From: syzbot
Date: Wed Jul 10 2024 - 11:21:37 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 40ab9e0dc865 netxen_nic: Use {low,upp}er_32_bits() helpers
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14ce4831980000
kernel config: https://syzkaller.appspot.com/x/.config?x=db697e01efa9d1d7
dashboard link: https://syzkaller.appspot.com/bug?extid=e227429f6fa77945d7e4
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/82323446a05a/disk-40ab9e0d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9ef73ffa3427/vmlinux-40ab9e0d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/38572b425814/bzImage-40ab9e0d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e227429f6fa77945d7e4@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc6-syzkaller-01403-g40ab9e0dc865 #0 Not tainted
------------------------------------------------------
syz.1.1201/8409 is trying to acquire lock:
ffffffff8f5e9108 (rtnl_mutex){+.+.}-{3:3}, at: ip_mroute_setsockopt+0x15b/0x1190 net/ipv4/ipmr.c:1369

but task is already holding lock:
ffff88805f784c50 (&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_INET6){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
lock_sock_nested+0x48/0x100 net/core/sock.c:3543
do_ipv6_setsockopt+0xbf3/0x3630 net/ipv6/ipv6_sockglue.c:567
ipv6_setsockopt+0x5c/0x1a0 net/ipv6/ipv6_sockglue.c:993
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
ip_mroute_setsockopt+0x15b/0x1190 net/ipv4/ipmr.c:1369
do_ip_setsockopt+0x129f/0x3cd0 net/ipv4/ip_sockglue.c:948
ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417
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_INET6 --> &smc->clcsock_release_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&smc->clcsock_release_lock);
lock(sk_lock-AF_INET6);
lock(&smc->clcsock_release_lock);
lock(rtnl_mutex);

*** DEADLOCK ***

1 lock held by syz.1.1201/8409:
#0: ffff88805f784c50 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_setsockopt+0x1c3/0xe50 net/smc/af_smc.c:3064

stack backtrace:
CPU: 0 PID: 8409 Comm: syz.1.1201 Not tainted 6.10.0-rc6-syzkaller-01403-g40ab9e0dc865 #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
ip_mroute_setsockopt+0x15b/0x1190 net/ipv4/ipmr.c:1369
do_ip_setsockopt+0x129f/0x3cd0 net/ipv4/ip_sockglue.c:948
ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417
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: 0033:0x7f5dfd375bd9
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:00007f5dfe06b048 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f5dfd503f60 RCX: 00007f5dfd375bd9
RDX: 00000000000000ca RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f5dfd3e4e60 R08: 0000000000000010 R09: 0000000000000000
R10: 0000000020000100 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f5dfd503f60 R15: 00007fff4a8a5b18
</TASK>

---
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Next message: Roger Quadros: "Re: [PATCH v2] phy: cadence-torrent: add support for three or more links using 2 protocols"
Previous message: Marc Zyngier: "Re: [PATCH v9 13/39] KVM: arm64: Manage GCS registers for guests"
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