Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com
Tested-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com

Tested on:

commit:         2f27fce6 Merge tag 'sound-6.12-rc1' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a844a9980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c7e7e5a089fe8488
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1532469f980000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 752e2217d789be2c6a6ac66554b981cd71cd9f31
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date:   Mon Apr 7 17:03:17 2025 +0000

    smc: Fix lockdep false-positive for IPPROTO_SMC.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17cd6bf4580000
start commit:   88d324e69ea9 Merge tag 'spi-fix-v6.14-rc7' of git://git.ke..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=27515cfdbafbb90d
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12b13e98580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=131d9c4c580000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: smc: Fix lockdep false-positive for IPPROTO_SMC.

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file net/ipv4/ip_sockglue.c
patch: **** unexpected end of file in patch



Tested on:

commit:         2f27fce6 Merge tag 'sound-6.12-rc1' of git://git.kerne..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=4fc2afd52fd008bb
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=152784a9980000

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[Ananta Srikar Puranam]

#syz test 
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
2f27fce67173bbb05d5a0ee03dae5c021202c912

Fixed the circular lock dependency reported by syzkaller.

Signed-off-by: Ananta Srikar <srikarananta01@gmail.com>
Reported-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
Fixes: d2bafcf224f3 ("Merge tag 'cgroup-for-6.11-rc4-fixes' of 
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup")
---
  net/ipv4/ip_sockglue.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index cf377377b52d..a8f46d1ba62b 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1073,9 +1073,11 @@ int do_ip_setsockopt(struct sock *sk, int level, 
int optname,
      }

      err = 0;
+
+    sockopt_lock_sock(sk);
+
      if (needs_rtnl)
          rtnl_lock();
-    sockopt_lock_sock(sk);

      switch (optname) {
      case IP_OPTIONS:
-- 
2.43.0

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[Ananta Srikar Puranam]

Fixed the circular lock dependency reported by syzkaller.

Signed-off-by: Ananta Srikar <srikarananta01@gmail.com>
Reported-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
Fixes: d2bafcf224f3 ("Merge tag 'cgroup-for-6.11-rc4-fixes' of 
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup")
---
  net/ipv4/ip_sockglue.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index cf377377b52d..a8f46d1ba62b 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1073,9 +1073,11 @@ int do_ip_setsockopt(struct sock *sk, int level, 
int optname,
  	}

  	err = 0;
+
+	sockopt_lock_sock(sk);
+
  	if (needs_rtnl)
  		rtnl_lock();
-	sockopt_lock_sock(sk);

  	switch (optname) {
  	case IP_OPTIONS:
-- 
2.43.0

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in do_ip_setsockopt

======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-04557-g2f27fce67173-dirty #0 Not tainted
------------------------------------------------------
syz.0.15/6023 is trying to acquire lock:
ffff888025c40918 (sk_lock-AF_INET){+.+.}-{0:0}, at: do_ip_setsockopt+0x1a2d/0x3cd0 net/ipv4/ip_sockglue.c:1078

but task is already holding lock:
ffffffff8faa9708 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (rtnl_mutex){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       smc_vlan_by_tcpsk+0x399/0x4e0 net/smc/smc_core.c:1898
       __smc_connect+0x292/0x1850 net/smc/af_smc.c:1518
       smc_connect+0x868/0xde0 net/smc/af_smc.c:1694
       __sys_connect_file net/socket.c:2067 [inline]
       __sys_connect+0x2d1/0x300 net/socket.c:2084
       __do_sys_connect net/socket.c:2094 [inline]
       __se_sys_connect net/socket.c:2091 [inline]
       __x64_sys_connect+0x7a/0x90 net/socket.c:2091
       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 (sk_lock-AF_INET){+.+.}-{0:0}:
       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+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       lock_sock_nested+0x48/0x100 net/core/sock.c:3611
       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:2330
       __sys_setsockopt+0x1a8/0x250 net/socket.c:2353
       __do_sys_setsockopt net/socket.c:2362 [inline]
       __se_sys_setsockopt net/socket.c:2359 [inline]
       __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2359
       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(rtnl_mutex);
                               lock(sk_lock-AF_INET);
                               lock(rtnl_mutex);
  lock(sk_lock-AF_INET);

 *** DEADLOCK ***

1 lock held by syz.0.15/6023:
 #0: ffffffff8faa9708 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077

stack backtrace:
CPU: 0 UID: 0 PID: 6023 Comm: syz.0.15 Not tainted 6.11.0-syzkaller-04557-g2f27fce67173-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 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+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 lock_sock_nested+0x48/0x100 net/core/sock.c:3611
 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:2330
 __sys_setsockopt+0x1a8/0x250 net/socket.c:2353
 __do_sys_setsockopt net/socket.c:2362 [inline]
 __se_sys_setsockopt net/socket.c:2359 [inline]
 __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2359
 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: 0033:0x7f34b9b79e79
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:00007f34b95ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f34b9d15f80 RCX: 00007f34b9b79e79
RDX: 0000000000000023 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f34b9be793e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f34b9d15f80 R15: 00007ffd22175db8
 </TASK>


Tested on:

commit:         2f27fce6 Merge tag 'sound-6.12-rc1' of git://git.kerne..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=104cb500580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c7e7e5a089fe8488
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[Ananta Srikar Puranam]

#syz test: 
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
2f27fce67173bbb05d5a0ee03dae5c021202c912

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

syzbot has bisected this issue to:

commit d25a92ccae6bed02327b63d138e12e7806830f78
Author: D. Wythe <alibuda@linux.alibaba.com>
Date:   Thu Jun 13 18:00:30 2024 +0000

    net/smc: Introduce IPPROTO_SMC

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15e95825980000
start commit:   d2bafcf224f3 Merge tag 'cgroup-for-6.11-rc4-fixes' of git:..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=17e95825980000
console output: https://syzkaller.appspot.com/x/log.txt?x=13e95825980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4fc2afd52fd008bb
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10e70233980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10a44815980000

Reported-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com
Fixes: d25a92ccae6b ("net/smc: Introduce IPPROTO_SMC")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d2bafcf224f3 Merge tag 'cgroup-for-6.11-rc4-fixes' of git:..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1214fd05980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4fc2afd52fd008bb
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10e70233980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10a44815980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8864ed10d80d/disk-d2bafcf2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6165bc385834/vmlinux-d2bafcf2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/83bf9db2da50/bzImage-d2bafcf2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc4-syzkaller-00255-gd2bafcf224f3 #0 Not tainted
------------------------------------------------------
syz-executor266/5220 is trying to acquire lock:
ffff888017752958 (sk_lock-AF_INET){+.+.}-{0:0}, at: do_ip_setsockopt+0x1a2d/0x3cd0 net/ipv4/ip_sockglue.c:1078

but task is already holding lock:
ffffffff8fa72248 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (rtnl_mutex){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       smc_vlan_by_tcpsk+0x399/0x4e0 net/smc/smc_core.c:1853
       __smc_connect+0x2a4/0x1890 net/smc/af_smc.c:1522
       smc_connect+0x868/0xde0 net/smc/af_smc.c:1702
       __sys_connect_file net/socket.c:2061 [inline]
       __sys_connect+0x2df/0x310 net/socket.c:2078
       __do_sys_connect net/socket.c:2088 [inline]
       __se_sys_connect net/socket.c:2085 [inline]
       __x64_sys_connect+0x7a/0x90 net/socket.c:2085
       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 (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+0x18e0/0x5900 kernel/locking/lockdep.c:3868
       __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       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

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz-executor266/5220:
 #0: ffffffff8fa72248 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077

stack backtrace:
CPU: 1 UID: 0 PID: 5220 Comm: syz-executor266 Not tainted 6.11.0-rc4-syzkaller-00255-gd2bafcf224f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 check_noncircular+0x36a/0x4a0 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+0x18e0/0x5900 kernel/locking/lockdep.c:3868
 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
 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
RIP: 0033:0x7f9dbe0ada79
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcf0f564e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9dbe0ada79
RDX: 0000000000000023 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f9dbe1205f0 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot] [net?] possible deadlock in do_ip_setsockopt (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    73cfd947dbdb net: ethernet: mtk_eth_soc: ppe: prevent ppe ..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=139ee301980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e78fc116033e0ab7
dashboard link: https://syzkaller.appspot.com/bug?extid=e4c27043b9315839452d
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/f7f95ead320b/disk-73cfd947.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2bb36264003f/vmlinux-73cfd947.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d854697a8694/bzImage-73cfd947.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e4c27043b9315839452d@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc4-syzkaller-00909-g73cfd947dbdb #0 Not tainted
------------------------------------------------------
syz.2.3207/15261 is trying to acquire lock:
ffffffff8f5e7288 (rtnl_mutex){+.+.}-{3:3}, at: do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077

but task is already holding lock:
ffff88804708c150 (&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_INET){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       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: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
       do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077
       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_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.2.3207/15261:
 #0: ffff88804708c150 (&smc->clcsock_release_lock){+.+.}-{3:3}, at: smc_setsockopt+0x1c3/0xe50 net/smc/af_smc.c:3064

stack backtrace:
CPU: 0 PID: 15261 Comm: syz.2.3207 Not tainted 6.10.0-rc4-syzkaller-00909-g73cfd947dbdb #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
 do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077
 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: 0033:0x7fec50775ae9
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:00007fec514fe048 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fec50903fa0 RCX: 00007fec50775ae9
RDX: 0000000000000023 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fec507f6746 R08: 000000000000000c R09: 0000000000000000
R10: 000000002000e040 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fec50903fa0 R15: 00007fff4616c208
 </TASK>


---
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