Subject: general protection fault in gc_worker

From: syzbot <[email-masked]>
Date: Sun, 01 Mar 2020 03:21:12 -0800

Hello,

syzbot found the following crash on:

HEAD commit:    f8788d86 Linux 5.6-rc3
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=104263a1e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9833e26bab355358
dashboard link: https://syzkaller.appspot.com/bug?extid=2a2fe383b2ce0e44b6ea
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 PID: 22524 Comm: kworker/0:10 Not tainted 5.6.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
RIP: 0010:nf_ct_tuplehash_to_ctrack include/net/netfilter/nf_conntrack.h:113 [inline]
RIP: 0010:gc_worker+0x3b1/0xdd0 net/netfilter/nf_conntrack_core.c:1390
Code: e8 03 4c 01 f8 85 db 48 89 85 70 ff ff ff 0f 85 53 03 00 00 e8 10 9d 01 fb 49 8d 7e 37 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <42> 0f b6 04 38 38 d0 7f 08 84 c0 0f 85 c4 08 00 00 41 0f b6 46 37
RSP: 0018:ffffc9000604fc40 EFLAGS: 00010202
RAX: 0000000000000006 RBX: 0000000000000000 RCX: ffffffff8673ed86
RDX: 0000000000000007 RSI: ffffffff8673ea40 RDI: 0000000000000037
RBP: ffffc9000604fd20 R08: ffff8880a25f23c0 R09: ffffed1000025fb8
R10: ffffed1000025fb7 R11: ffff88800012fdbb R12: ffff88800012fdb8
R13: 0000000000010000 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005014d000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace 3051a0fdf6c90610 ]---
RIP: 0010:nf_ct_tuplehash_to_ctrack include/net/netfilter/nf_conntrack.h:113 [inline]
RIP: 0010:gc_worker+0x3b1/0xdd0 net/netfilter/nf_conntrack_core.c:1390
Code: e8 03 4c 01 f8 85 db 48 89 85 70 ff ff ff 0f 85 53 03 00 00 e8 10 9d 01 fb 49 8d 7e 37 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <42> 0f b6 04 38 38 d0 7f 08 84 c0 0f 85 c4 08 00 00 41 0f b6 46 37
RSP: 0018:ffffc9000604fc40 EFLAGS: 00010202
RAX: 0000000000000006 RBX: 0000000000000000 RCX: ffffffff8673ed86
RDX: 0000000000000007 RSI: ffffffff8673ea40 RDI: 0000000000000037
RBP: ffffc9000604fd20 R08: ffff8880a25f23c0 R09: ffffed1000025fb8
R10: ffffed1000025fb7 R11: ffff88800012fdbb R12: ffff88800012fdb8
R13: 0000000000010000 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000928000 CR3: 0000000217f1b000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
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