[syzbot] [hams?] general protection fault in prepare_to_wait (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=152cdb63a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a80fc3a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e03bf2f0ff9c/disk-ace0ab3a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ad6e79c01723/vmlinux-ace0ab3a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/617319e5afb7/bzImage-ace0ab3a.xz

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=157eda9ba80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=177eda9ba80000
console output: https://syzkaller.appspot.com/x/log.txt?x=137eda9ba80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+666c97...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5059 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 11 6e 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 69 48 90 0f 84 96 0d 00
RSP: 0018:ffffc90003d6f9e0 EFLAGS: 00010006
RAX: ffff8880244c8000 RBX: 1ffff920007adf6c RCX: 0000000000000003
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000018
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000018 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f51d519a6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f51d5158d58 CR3: 000000002943f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5761 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
prepare_to_wait+0x47/0x380 kernel/sched/wait.c:269
nr_accept+0x20d/0x650 net/netrom/af_netrom.c:798
do_accept+0x3a6/0x570 net/socket.c:1872
__sys_accept4_file net/socket.c:1913 [inline]
__sys_accept4+0x99/0x120 net/socket.c:1943
__do_sys_accept4 net/socket.c:1954 [inline]
__se_sys_accept4 net/socket.c:1951 [inline]
__x64_sys_accept4+0x96/0x100 net/socket.c:1951
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f51d447cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f51d519a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: ffffffffffffffda RBX: 00007f51d459bf80 RCX: 00007f51d447cae9
RDX: 0000000020000400 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f51d44c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f51d459bf80 R15: 00007ffc25c34e48
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 11 6e 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 69 48 90 0f 84 96 0d 00
RSP: 0018:ffffc90003d6f9e0 EFLAGS: 00010006
RAX: ffff8880244c8000 RBX: 1ffff920007adf6c RCX: 0000000000000003
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000018
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000018 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f51d519a6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f51d5158d58 CR3: 000000002943f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 45 85 c9 test %r9d,%r9d
3: 0f 84 cc 0e 00 00 je 0xed5
9: 44 8b 05 11 6e 23 0b mov 0xb236e11(%rip),%r8d # 0xb236e21
10: 45 85 c0 test %r8d,%r8d
13: 0f 84 be 0d 00 00 je 0xdd7
19: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
20: fc ff df
23: 4c 89 d1 mov %r10,%rcx
26: 48 c1 e9 03 shr $0x3,%rcx
* 2a: 80 3c 11 00 cmpb $0x0,(%rcx,%rdx,1) <-- trapping instruction
2e: 0f 85 e8 40 00 00 jne 0x411c
34: 49 81 3a a0 69 48 90 cmpq $0xffffffff904869a0,(%r10)
3b: 0f .byte 0xf
3c: 84 .byte 0x84
3d: 96 xchg %eax,%esi
3e: 0d .byte 0xd


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Fri, 18 Aug 2023 09:36:53 -0700

> HEAD commit: ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
> git tree: net

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a80fc3a80000

Use sock->wq instead.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git ace0ab3a4b54

--- x/net/netrom/af_netrom.c
+++ y/net/netrom/af_netrom.c
@@ -735,7 +735,7 @@ static int nr_connect(struct socket *soc
DEFINE_WAIT(wait);

for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait,
+ prepare_to_wait(&sock->wq, &wait,
TASK_INTERRUPTIBLE);
if (sk->sk_state != TCP_SYN_SENT)
break;
@@ -748,7 +748,7 @@ static int nr_connect(struct socket *soc
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);
+ finish_wait(&sock->wq, &wait);
if (err)
goto out_release;
}
@@ -795,7 +795,7 @@ static int nr_accept(struct socket *sock
* hooked into the SABM we saved
*/
for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ prepare_to_wait(&sock->wq, &wait, TASK_INTERRUPTIBLE);
skb = skb_dequeue(&sk->sk_receive_queue);
if (skb)
break;
@@ -813,7 +813,7 @@ static int nr_accept(struct socket *sock
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);
+ finish_wait(&sock->wq, &wait);
if (err)
goto out_release;

--

[syzbot]

Hello,

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

net/netrom/af_netrom.c:738:41: error: passing argument 1 of 'prepare_to_wait' from incompatible pointer type [-Werror=incompatible-pointer-types]
net/netrom/af_netrom.c:751:29: error: passing argument 1 of 'finish_wait' from incompatible pointer type [-Werror=incompatible-pointer-types]
net/netrom/af_netrom.c:798:33: error: passing argument 1 of 'prepare_to_wait' from incompatible pointer type [-Werror=incompatible-pointer-types]
net/netrom/af_netrom.c:816:21: error: passing argument 1 of 'finish_wait' from incompatible pointer type [-Werror=incompatible-pointer-types]


Tested on:

commit: ace0ab3a Revert "vlan: Fix VLAN 0 memory leak"
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git

kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=138bc6e3a80000

[Hillf Danton]

On Fri, 18 Aug 2023 09:36:53 -0700

> HEAD commit: ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
> git tree: net

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a80fc3a80000

Use sock->wq.wait instead.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git ace0ab3a4b54

--- x/net/netrom/af_netrom.c
+++ y/net/netrom/af_netrom.c
@@ -735,7 +735,7 @@ static int nr_connect(struct socket *soc
DEFINE_WAIT(wait);

for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait,

+ prepare_to_wait(&sock->wq.wait, &wait,

TASK_INTERRUPTIBLE);
if (sk->sk_state != TCP_SYN_SENT)
break;
@@ -748,7 +748,7 @@ static int nr_connect(struct socket *soc
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);

+ finish_wait(&sock->wq.wait, &wait);

if (err)
goto out_release;
}
@@ -795,7 +795,7 @@ static int nr_accept(struct socket *sock
* hooked into the SABM we saved
*/
for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

+ prepare_to_wait(&sock->wq.wait, &wait, TASK_INTERRUPTIBLE);

skb = skb_dequeue(&sk->sk_receive_queue);
if (skb)
break;
@@ -813,7 +813,7 @@ static int nr_accept(struct socket *sock
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);

+ finish_wait(&sock->wq.wait, &wait);

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+666c97...@syzkaller.appspotmail.com

Tested on:

commit: ace0ab3a Revert "vlan: Fix VLAN 0 memory leak"
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16463d37a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=14730040680000

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

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

On Mon, Fri, 18 Aug 2023 09:36:53 -0700

> HEAD commit: ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
> git tree: net
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=152cdb63a80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
> dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a80fc3a80000

syzbot report:

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5059 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 11 6e 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 69 48 90 0f 84 96 0d 00

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git ace0ab3a4b54

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 111607d91489..124b4b7b793f 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -5009,6 +5009,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (unlikely(!debug_locks))
return 0;

+ if (unlikely(!lock))
+ return 0;
+
if (!prove_locking || lock->key == &__lockdep_no_validate__)
check = 0;

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in prepare_to_wait

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]

CPU: 0 PID: 5439 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

RIP: 0010:__lock_acquire+0x105/0x5db0 kernel/locking/lockdep.c:5015
Code: 4d 85 ed 0f 84 cc 0d 00 00 44 8b 35 15 6e 23 0b 45 85 f6 0f 84 45 0e 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 bb 40 00 00 49 81 7d 00 a0 69 48 90 0f 84 1c 0e
RSP: 0018:ffffc90002d7f9e8 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 1ffff920005aff6d RCX: 0000000000000000
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000018

RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001

R10: ffffffff8eab9f57 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000018 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f01e25b86c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007ffc9dd91e58 CR3: 000000002a9f8000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>

lock_acquire kernel/locking/lockdep.c:5764 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5729

__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
prepare_to_wait+0x47/0x380 kernel/sched/wait.c:269
nr_accept+0x20d/0x650 net/netrom/af_netrom.c:798
do_accept+0x3a6/0x570 net/socket.c:1872
__sys_accept4_file net/socket.c:1913 [inline]
__sys_accept4+0x99/0x120 net/socket.c:1943

__do_sys_accept net/socket.c:1960 [inline]
__se_sys_accept net/socket.c:1957 [inline]
__x64_sys_accept+0x74/0xb0 net/socket.c:1957

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f01e187cae9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f01e25b80c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 00007f01e199bf80 RCX: 00007f01e187cae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f01e18c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f01e199bf80 R15: 00007ffdf7ebfdc8

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---

RIP: 0010:__lock_acquire+0x105/0x5db0 kernel/locking/lockdep.c:5015
Code: 4d 85 ed 0f 84 cc 0d 00 00 44 8b 35 15 6e 23 0b 45 85 f6 0f 84 45 0e 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 bb 40 00 00 49 81 7d 00 a0 69 48 90 0f 84 1c 0e
RSP: 0018:ffffc90002d7f9e8 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 1ffff920005aff6d RCX: 0000000000000000
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000018

RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001

R10: ffffffff8eab9f57 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000018 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f01e25b86c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007ffc9dd91e58 CR3: 000000002a9f8000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):

0: 4d 85 ed test %r13,%r13
3: 0f 84 cc 0d 00 00 je 0xdd5
9: 44 8b 35 15 6e 23 0b mov 0xb236e15(%rip),%r14d # 0xb236e25
10: 45 85 f6 test %r14d,%r14d
13: 0f 84 45 0e 00 00 je 0xe5e
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 4c 89 ea mov %r13,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 bb 40 00 00 jne 0x40ef
34: 49 81 7d 00 a0 69 48 cmpq $0xffffffff904869a0,0x0(%r13)
3b: 90
3c: 0f .byte 0xf
3d: 84 1c 0e test %bl,(%rsi,%rcx,1)


Tested on:

commit: ace0ab3a Revert "vlan: Fix VLAN 0 memory leak"
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1737025ba80000

kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1409120fa80000

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

On Mon, Fri, 18 Aug 2023 09:36:53 -0700

> HEAD commit: ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
> git tree: net
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=152cdb63a80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
> dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a80fc3a80000

syzbot report:

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5059 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 11 6e 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 69 48 90 0f 84 96 0d 00

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git ace0ab3a4b54

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 111607d91489..124b4b7b793f 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -5009,6 +5009,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (unlikely(!debug_locks))
return 0;

+ if (unlikely(!lock))
+ return 0;
+
if (!prove_locking || lock->key == &__lockdep_no_validate__)
check = 0;

diff --git a/include/net/sock.h b/include/net/sock.h
index c4b91fc19b9c..4edc64674eb0 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2014,8 +2014,12 @@ static inline void sk_set_socket(struct sock *sk, struct socket *sock)

static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
+ wait_queue_head_t *wq = NULL;
BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
- return &rcu_dereference_raw(sk->sk_wq)->wait;
+ wq = &rcu_dereference_raw(sk->sk_wq)->wait;
+ if (!wq)
+ wq = &sk->sk_socket->wq.wait;
+ return wq;
}
/* Detach socket from process context.
* Announce socket dead, detach it from wait queue and inode.
@@ -2029,7 +2033,7 @@ static inline void sock_orphan(struct sock *sk)
write_lock_bh(&sk->sk_callback_lock);
sock_set_flag(sk, SOCK_DEAD);
sk_set_socket(sk, NULL);
- sk->sk_wq = NULL;
+ rcu_assign_pointer(sk->sk_wq, NULL);
write_unlock_bh(&sk->sk_callback_lock);
}

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in prepare_to_wait

general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 1 PID: 5437 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

RIP: 0010:__lock_acquire+0x105/0x5db0 kernel/locking/lockdep.c:5015

Code: 4d 85 ed 0f 84 cc 0d 00 00 44 8b 35 15 6e 23 0b 45 85 f6 0f 84 45 0e 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 bb 40 00 00 49 81 7d 00 a0 69 48 90 0f 84 1c 0e
RSP: 0018:ffffc90005abf9e0 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 1ffff92000b57f6c RCX: 0000000000000000
RDX: 000000000000000b RSI: 0000000000000000 RDI: 0000000000000058

RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8eab9f57 R11: 0000000000000000 R12: 0000000000000000

R13: 0000000000000058 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f53c5c566c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f9252e4d3f1 CR3: 0000000067e5e000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5764 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5729
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
prepare_to_wait+0x47/0x380 kernel/sched/wait.c:269

nr_accept+0x21e/0x6f0 net/netrom/af_netrom.c:798

do_accept+0x3a6/0x570 net/socket.c:1872
__sys_accept4_file net/socket.c:1913 [inline]
__sys_accept4+0x99/0x120 net/socket.c:1943
__do_sys_accept net/socket.c:1960 [inline]
__se_sys_accept net/socket.c:1957 [inline]
__x64_sys_accept+0x74/0xb0 net/socket.c:1957
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f53c4e7cae9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f53c5c560c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 00007f53c4f9bf80 RCX: 00007f53c4e7cae9

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004

RBP: 00007f53c4ec847a R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 000000000000000b R14: 00007f53c4f9bf80 R15: 00007ffc263ffbc8

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__lock_acquire+0x105/0x5db0 kernel/locking/lockdep.c:5015

Code: 4d 85 ed 0f 84 cc 0d 00 00 44 8b 35 15 6e 23 0b 45 85 f6 0f 84 45 0e 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 bb 40 00 00 49 81 7d 00 a0 69 48 90 0f 84 1c 0e
RSP: 0018:ffffc90005abf9e0 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 1ffff92000b57f6c RCX: 0000000000000000
RDX: 000000000000000b RSI: 0000000000000000 RDI: 0000000000000058

RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8eab9f57 R11: 0000000000000000 R12: 0000000000000000

R13: 0000000000000058 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f53c5c566c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f9252e4d3f1 CR3: 0000000067e5e000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 4d 85 ed test %r13,%r13
3: 0f 84 cc 0d 00 00 je 0xdd5
9: 44 8b 35 15 6e 23 0b mov 0xb236e15(%rip),%r14d # 0xb236e25
10: 45 85 f6 test %r14d,%r14d
13: 0f 84 45 0e 00 00 je 0xe5e
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 4c 89 ea mov %r13,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 bb 40 00 00 jne 0x40ef
34: 49 81 7d 00 a0 69 48 cmpq $0xffffffff904869a0,0x0(%r13)
3b: 90
3c: 0f .byte 0xf
3d: 84 1c 0e test %bl,(%rsi,%rcx,1)


Tested on:

commit: ace0ab3a Revert "vlan: Fix VLAN 0 memory leak"
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=11a276cfa80000

kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=164dca40680000

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

On Mon, Fri, 18 Aug 2023 09:36:53 -0700

> HEAD commit: ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
> git tree: net
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=152cdb63a80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
> dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a80fc3a80000

syzbot report:

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5059 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 11 6e 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 69 48 90 0f 84 96 0d 00

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git ace0ab3a4b54

diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index eb8ccbd58d..c84a4c65b3 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -732,23 +732,18 @@ static int nr_connect(struct socket *sock, struct sockaddr *uaddr,
* closed.
*/
if (sk->sk_state == TCP_SYN_SENT) {
- DEFINE_WAIT(wait);
-

for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait,

- TASK_INTERRUPTIBLE);

if (sk->sk_state != TCP_SYN_SENT)
break;

if (!signal_pending(current)) {
release_sock(sk);
- schedule();
+ schedule_timeout_interruptible(HZ/10);
lock_sock(sk);
continue;

}
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);

if (err)
goto out_release;
}
@@ -772,7 +767,6 @@ static int nr_accept(struct socket *sock, struct socket *newsock, int flags,
{
struct sk_buff *skb;
struct sock *newsk;
- DEFINE_WAIT(wait);
struct sock *sk;
int err = 0;

@@ -795,7 +789,6 @@ static int nr_accept(struct socket *sock, struct socket *newsock, int flags,

* hooked into the SABM we saved
*/
for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

skb = skb_dequeue(&sk->sk_receive_queue);
if (skb)
break;

@@ -806,14 +799,13 @@ static int nr_accept(struct socket *sock, struct socket *newsock, int flags,
}
if (!signal_pending(current)) {
release_sock(sk);
- schedule();
+ schedule_timeout_uninterruptible(HZ/10);
lock_sock(sk);
continue;

}
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);

if (err)
goto out_release;

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+666c97...@syzkaller.appspotmail.com

Tested on:

commit: ace0ab3a Revert "vlan: Fix VLAN 0 memory leak"
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git

console output: https://syzkaller.appspot.com/x/log.txt?x=133c0a60680000

kernel config: https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=16c04bf3a80000

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

The parameter sk_sleep(sk) passed in when calling prepare_to_wait may
return an invalid pointer due to nr-release reclaiming the sock.
Here, schedule_timeout_interruptible is used to replace the combination
of 'prepare_to_wait, schedule, finish_wait' to solve the problem.

Reported-and-tested-by: syzbot+666c97...@syzkaller.appspotmail.com
Signed-off-by: Edward AD <ead...@sina.com>
---
net/netrom/af_netrom.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index eb8ccbd58d..c84a4c65b3 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -732,23 +732,18 @@ static int nr_connect(struct socket *sock, struct sockaddr *uaddr,
* closed.
*/
if (sk->sk_state == TCP_SYN_SENT) {
- DEFINE_WAIT(wait);
-
for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait,
- TASK_INTERRUPTIBLE);
if (sk->sk_state != TCP_SYN_SENT)
break;
if (!signal_pending(current)) {
release_sock(sk);
- schedule();

+ schedule_timeout_interruptible(HZ);

+ schedule_timeout_uninterruptible(HZ);

lock_sock(sk);
continue;
}
err = -ERESTARTSYS;
break;
}
- finish_wait(sk_sleep(sk), &wait);
if (err)
goto out_release;

--
2.25.1

[Paolo Abeni]

On Tue, 2023-08-22 at 20:44 +0800, ead...@sina.com wrote:
> From: Edward AD <ead...@sina.com>
>
> The parameter sk_sleep(sk) passed in when calling prepare_to_wait may
> return an invalid pointer due to nr-release reclaiming the sock.
> Here, schedule_timeout_interruptible is used to replace the combination
> of 'prepare_to_wait, schedule, finish_wait' to solve the problem.
>
> Reported-and-tested-by: syzbot+666c97...@syzkaller.appspotmail.com
> Signed-off-by: Edward AD <ead...@sina.com>

This looks wrong. No syscall should race with sock_release(). It looks
like you are papering over the real issue.

As the reproducer shows a disconnect on an connected socket, I'm wild
guessing something alike 4faeee0cf8a5d88d63cdbc3bab124fb0e6aed08c
should be more appropriate.

Cheers,

Paolo

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

There is insufficient evidence to prove where the current report provided by
syz caused 'sk_sleep()' to return an invalid pointer.
So, the above statement is my guess.