kernel BUG at mm/slab.c:LINE! (3)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 3e536cff3424 net: phy: check if advertising is zero using ..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16f95b83400000
kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a89f12ca9b0f5
dashboard link: https://syzkaller.appspot.com/bug?extid=2182db487a523d86bf34
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148d46d5400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c6a225400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2182db...@syzkaller.appspotmail.com

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)
------------[ cut here ]------------
kernel BUG at mm/slab.c:4425!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: -642842048 Comm: ksoftirqd/0 Not tainted 4.20.0-rc2+ #294
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__check_heap_object+0xa7/0xb5 mm/slab.c:4450
Code: 48 c7 c7 15 73 12 89 e8 97 e3 0a 00 5d c3 41 8b 91 04 01 00 00 48 29
c7 48 39 d7 77 be 48 01 d0 48 29 c8 48 39 f0 72 b3 5d c3 <0f> 0b 48 c7 c7
15 73 12 89 e8 fd eb 0a 00 44 89 e9 48 c7 c7 d0 73
RSP: 0018:ffff8881d9af0030 EFLAGS: 00010093
RAX: 00000000000a57eb RBX: 1ffff1103b35e00d RCX: 000000000000000c
RDX: ffff8881d9af0240 RSI: 0000000000000002 RDI: ffff8881d9af01d8
RBP: ffff8881d9af0030 R08: ffff8881d9af0240 R09: ffff8881da970180
R10: 000000004afd69e7 R11: 0000000000000000 R12: ffff8881d9af01d8
R13: 0000000000000002 R14: ffffea000766bc00 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000068 CR3: 00000001bb987000 CR4: 00000000001406f0
Call Trace:
Modules linked in:
---[ end trace 1c9eb38e9e38ee03 ]---
RIP: 0010:__check_heap_object+0xa7/0xb5 mm/slab.c:4450
Code: 48 c7 c7 15 73 12 89 e8 97 e3 0a 00 5d c3 41 8b 91 04 01 00 00 48 29
c7 48 39 d7 77 be 48 01 d0 48 29 c8 48 39 f0 72 b3 5d c3 <0f> 0b 48 c7 c7
15 73 12 89 e8 fd eb 0a 00 44 89 e9 48 c7 c7 d0 73
RSP: 0018:ffff8881d9af0030 EFLAGS: 00010093
RAX: 00000000000a57eb RBX: 1ffff1103b35e00d RCX: 000000000000000c
RDX: ffff8881d9af0240 RSI: 0000000000000002 RDI: ffff8881d9af01d8
RBP: ffff8881d9af0030 R08: ffff8881d9af0240 R09: ffff8881da970180
R10: 000000004afd69e7 R11: 0000000000000000 R12: ffff8881d9af01d8
R13: 0000000000000002 R14: ffffea000766bc00 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000068 CR3: 00000001bb987000 CR4: 00000000001406f0


---
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[Dmitry Vyukov]

On Tue, Nov 13, 2018 at 11:18 PM, syzbot
<syzbot+2182db...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 3e536cff3424 net: phy: check if advertising is zero using ..
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=16f95b83400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a89f12ca9b0f5
> dashboard link: https://syzkaller.appspot.com/bug?extid=2182db487a523d86bf34
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148d46d5400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c6a225400000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+2182db...@syzkaller.appspotmail.com

All reproducers just do something simple with inet6 sockets and all
crashes are on net-next, so +netdev

r0 = socket$inet6(0xa, 0x2, 0x0)
connect$inet6(r0, &(0x7f0000000080)={0xa, 0x4e24, 0x0, @ipv4={[], [],
@loopback}}, 0x1c)
sendmmsg(r0, &(0x7f00000092c0), 0x3ffffffffff0c00, 0x0)

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[syzbot]

syzbot has bisected this bug to:

commit b8a51b38e4d4dec3e379d52c0fe1a66827f7cf1e
Author: Stefano Brivio <sbr...@redhat.com>
Date: Thu Nov 8 11:19:23 2018 +0000

fou, fou6: ICMP error handlers for FoU and GUE

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=161b63cf200000
start commit: b8a51b38 fou, fou6: ICMP error handlers for FoU and GUE
git tree: net-next
final crash: https://syzkaller.appspot.com/x/report.txt?x=151b63cf200000
console output: https://syzkaller.appspot.com/x/log.txt?x=111b63cf200000

kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a89f12ca9b0f5
dashboard link: https://syzkaller.appspot.com/bug?extid=2182db487a523d86bf34

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148d46d5400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c6a225400000

Reported-by: syzbot+2182db...@syzkaller.appspotmail.com
Fixes: b8a51b38 ("fou, fou6: ICMP error handlers for FoU and GUE")

[Dmitry Vyukov]

That commit caused lots of crashes that look completely differently.
Now all that is fixed. The last crash for this bugs happened 2+ months
ago. So let's just do:

#syz fix:
fou: Prevent unbounded recursion in GUE error handler also with UDP-Lite