Re: general protection fault in list_lru_count_one

[Kirill Tkhai <ktkhai@virtuozzo.com>]

On 17.07.2018 16:15, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:A A A  483d835c8189 Add linux-next specific files for 20180713

483d835c8189 contains register_shrinker() in sget_fc(). It's fixed by 72589a599d79
and 2c028928aa4c, which came in next-20180716.

> git tree:A A A A A A  linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=169b4770400000
> kernel config:A  https://syzkaller.appspot.com/x/.config?x=60e5ac2478928314
> dashboard link: https://syzkaller.appspot.com/bug?extid=50d322b3e0b15a4a8d55
> compiler:A A A A A A  gcc (GCC) 8.0.1 20180413 (experimental)
> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=10faa9a4400000
> C reproducer:A A  https://syzkaller.appspot.com/x/repro.c?x=17f57794400000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+50d322b3e0b15a4a8d55@syzkaller.appspotmail.com
> 
> random: sshd: uninitialized urandom read (32 bytes read)
> random: sshd: uninitialized urandom read (32 bytes read)
> IPVS: ftp: loaded support on port[0] = 21
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> CPU: 0 PID: 4462 Comm: syz-executor763 Not tainted 4.18.0-rc4-next-20180713+ #7
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline]
> RIP: 0010:list_lru_from_memcg_idx mm/list_lru.c:56 [inline]
> RIP: 0010:list_lru_count_one+0x156/0x460 mm/list_lru.c:201
> Code: 08 3c 03 0f 8e b5 02 00 00 4d 63 bd d8 0a 00 00 e8 7f 35 d2 ff 48 8d 7b 50 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 d8 02 00 00 49 8d 46 c0 4c 8b 6b 50 48 ba 00 00
> RSP: 0018:ffff8801ac967198 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81aa3a64
> RDX: 000000000000000a RSI: ffffffff81aa3ad1 RDI: 0000000000000050
> RBP: ffff8801ac967228 R08: ffff8801af1c6300 R09: 0000000000000000
> R10: ffffed00359e0088 R11: ffff8801acf00447 R12: 1ffff1003592ce34
> R13: ffff8801ad6aa080 R14: ffff8801ac967200 R15: 0000000000000000
> FS:A  000000000206b880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
> CS:A  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000006ce080 CR3: 00000001ae3c1000 CR4: 00000000001406f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> A list_lru_shrink_count include/linux/list_lru.h:122 [inline]
> A super_cache_count+0x153/0x2e0 fs/super.c:146
> A do_shrink_slab+0x148/0xc50 mm/vmscan.c:458
> A shrink_slab_memcg mm/vmscan.c:598 [inline]
> A shrink_slab+0x861/0xa60 mm/vmscan.c:671
> A shrink_node+0x429/0x16a0 mm/vmscan.c:2735
> A shrink_zones mm/vmscan.c:2964 [inline]
> A do_try_to_free_pages+0x3e7/0x1290 mm/vmscan.c:3026
> A try_to_free_mem_cgroup_pages+0x49d/0xc90 mm/vmscan.c:3324
> A reclaim_high.constprop.73+0x137/0x1e0 mm/memcontrol.c:2060
> A mem_cgroup_handle_over_high+0x8d/0x130 mm/memcontrol.c:2085
> A tracehook_notify_resume include/linux/tracehook.h:195 [inline]
> A exit_to_usermode_loop+0x287/0x380 arch/x86/entry/common.c:166
> A prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
> A syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
> A do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
> A entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x440ec7
> Code: 1f 40 00 b8 5a 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 6d 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 4d 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007ffe197f4e98 EFLAGS: 00000202 ORIG_RAX: 0000000000000053
> RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000440ec7
> RDX: 00007ffe197f4eb3 RSI: 00000000000001ff RDI: 00007ffe197f4eb0
> RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000003
> R10: 0000000000000064 R11: 0000000000000202 R12: 0000000000000001
> R13: 0000000000008fab R14: 0000000000000000 R15: 0000000000000000
> Modules linked in:
> Dumping ftrace buffer:
> A A  (ftrace buffer empty)
> ---[ end trace 82052695a1b5b84c ]---
> RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline]
> RIP: 0010:list_lru_from_memcg_idx mm/list_lru.c:56 [inline]
> RIP: 0010:list_lru_count_one+0x156/0x460 mm/list_lru.c:201
> Code: 08 3c 03 0f 8e b5 02 00 00 4d 63 bd d8 0a 00 00 e8 7f 35 d2 ff 48 8d 7b 50 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 d8 02 00 00 49 8d 46 c0 4c 8b 6b 50 48 ba 00 00
> RSP: 0018:ffff8801ac967198 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81aa3a64
> RDX: 000000000000000a RSI: ffffffff81aa3ad1 RDI: 0000000000000050
> RBP: ffff8801ac967228 R08: ffff8801af1c6300 R09: 0000000000000000
> R10: ffffed00359e0088 R11: ffff8801acf00447 R12: 1ffff1003592ce34
> R13: ffff8801ad6aa080 R14: ffff8801ac967200 R15: 0000000000000000
> FS:A  000000000206b880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
> CS:A  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000006ce080 CR3: 00000001ae3c1000 CR4: 00000000001406f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> 
> 
> ---
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