general protection fault in llc_ui_bind

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: af1af6ebca0e Linux 4.14.274
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1373f367700000
kernel config: https://syzkaller.appspot.com/x/.config?x=425e8e4e86f35eba
dashboard link: https://syzkaller.appspot.com/bug?extid=d71f70b2ad08d37dee4c
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d71f70...@syzkaller.appspotmail.com

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 9539 Comm: syz-executor.3 Not tainted 4.14.274-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a21940c0 task.stack: ffff888094188000
RIP: 0010:dev_put include/linux/netdevice.h:3381 [inline]
RIP: 0010:llc_ui_bind+0x5ba/0xa40 net/llc/af_llc.c:427
RSP: 0018:ffff88809418fd40 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90007ff0000
RDX: 00000000000000a8 RSI: ffffffff85d0b322 RDI: 0000000000000540
RBP: ffff88809418fe30 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ac0d6b40
R13: 1ffff11012831fab R14: ffff8880af0c1340 R15: 0000000000000000
FS: 00007f6ff6133700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffda556ac10 CR3: 000000009bd0b000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
SYSC_bind net/socket.c:1489 [inline]
SyS_bind+0x174/0x1f0 net/socket.c:1475
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f6ff77be049
RSP: 002b:00007f6ff6133168 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00007f6ff78d0f60 RCX: 00007f6ff77be049
RDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 00007f6ff781808d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffefcf5f80f R14: 00007f6ff6133300 R15: 0000000000022000
Code: 4e 04 0f 88 8f 29 51 01 0f 84 b3 01 00 00 e8 1e 8f 84 fb 48 8d bb 40 05 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 0a 04 00 00 4c 89 e7 48 8b 83 40 05 00 00 65
RIP: dev_put include/linux/netdevice.h:3381 [inline] RSP: ffff88809418fd40
RIP: llc_ui_bind+0x5ba/0xa40 net/llc/af_llc.c:427 RSP: ffff88809418fd40
---[ end trace 4e25bcbbdab12cb4 ]---
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 0f 88 8f 29 51 01 js 0x1512995
6: 0f 84 b3 01 00 00 je 0x1bf
c: e8 1e 8f 84 fb callq 0xfb848f2f
11: 48 8d bb 40 05 00 00 lea 0x540(%rbx),%rdi
18: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1f: fc ff df
22: 48 89 fa mov %rdi,%rdx
25: 48 c1 ea 03 shr $0x3,%rdx
* 29: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2d: 0f 85 0a 04 00 00 jne 0x43d
33: 4c 89 e7 mov %r12,%rdi
36: 48 8b 83 40 05 00 00 mov 0x540(%rbx),%rax
3d: 65 gs


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: af1af6ebca0e Linux 4.14.274
git tree: linux-4.14.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1560f557700000

kernel config: https://syzkaller.appspot.com/x/.config?x=425e8e4e86f35eba
dashboard link: https://syzkaller.appspot.com/bug?extid=d71f70b2ad08d37dee4c
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=167556c7700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=157abcc3700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d71f70...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:

CPU: 0 PID: 7951 Comm: syz-executor102 Not tainted 4.14.274-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

task: ffff888097ecc4c0 task.stack: ffff8880b3ae8000

RIP: 0010:dev_put include/linux/netdevice.h:3381 [inline]
RIP: 0010:llc_ui_bind+0x5ba/0xa40 net/llc/af_llc.c:427

RSP: 0018:ffff8880b3aefd40 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffffffff127a4bc
RDX: 00000000000000a8 RSI: ffff888097eccd48 RDI: 0000000000000540
RBP: ffff8880b3aefe30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000001 R12: ffff8880947f0ac0
R13: 1ffff1101675dfab R14: 0000000000000000 R15: 00000000ffffffea
FS: 00005555563a6300(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000

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

CR2: 00007f843e849018 CR3: 00000000ab60c000 CR4: 00000000003406f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
SYSC_bind net/socket.c:1489 [inline]
SyS_bind+0x174/0x1f0 net/socket.c:1475
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb

RIP: 0033:0x7f3de773cfa9
RSP: 002b:00007fff38e8a1a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3de773cfa9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f3de7700f90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3de7701020
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Code: 4e 04 0f 88 8f 29 51 01 0f 84 b3 01 00 00 e8 1e 8f 84 fb 48 8d bb 40 05 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 0a 04 00 00 4c 89 e7 48 8b 83 40 05 00 00 65

RIP: dev_put include/linux/netdevice.h:3381 [inline] RSP: ffff8880b3aefd40
RIP: llc_ui_bind+0x5ba/0xa40 net/llc/af_llc.c:427 RSP: ffff8880b3aefd40
---[ end trace 50fe0e8df312a5ed ]---