Date:   Tue, 8 Dec 2020 08:25:30 +0100
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     syzbot <syzbot+ec2234240c96fdd26b93@...kaller.appspotmail.com>,
        guro@...com, Eric Dumazet <edumazet@...gle.com>
Cc:     andrii@...nel.org, Andrii Nakryiko <andriin@...com>,
        Alexei Starovoitov <ast@...nel.org>, bpf <bpf@...r.kernel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        David Miller <davem@...emloft.net>,
        Johannes Berg <johannes@...solutions.net>,
        John Fastabend <john.fastabend@...il.com>,
        Martin KaFai Lau <kafai@...com>,
        KP Singh <kpsingh@...omium.org>,
        Jakub Kicinski <kuba@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        netdev <netdev@...r.kernel.org>,
        Song Liu <songliubraving@...com>,
        syzkaller-bugs <syzkaller-bugs@...glegroups.com>,
        Yonghong Song <yhs@...com>
Subject: Re: BUG: unable to handle kernel paging request in bpf_lru_populate

On Mon, Dec 7, 2020 at 12:43 PM syzbot
<syzbot+ec2234240c96fdd26b93@...kaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    bcd684aa net/nfc/nci: Support NCI 2.x initial sequence
> git tree:       net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=12001bd3500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3cb098ab0334059f
> dashboard link: https://syzkaller.appspot.com/bug?extid=ec2234240c96fdd26b93
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11f7f2ef500000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=103833f7500000
>
> The issue was bisected to:
>
> commit b93ef089d35c3386dd197e85afb6399bbd54cfb3
> Author: Martin KaFai Lau <kafai@...com>
> Date:   Mon Nov 16 20:01:13 2020 +0000
>
>     bpf: Fix the irq and nmi check in bpf_sk_storage for tracing usage
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1103b837500000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=1303b837500000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1503b837500000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ec2234240c96fdd26b93@...kaller.appspotmail.com
> Fixes: b93ef089d35c ("bpf: Fix the irq and nmi check in bpf_sk_storage for tracing usage")

I assume this is also

#syz fix: bpf: Avoid overflows involving hash elem_size


> BUG: unable to handle page fault for address: fffff5200471266c
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 23fff2067 P4D 23fff2067 PUD 101a4067 PMD 32e3a067 PTE 0
> Oops: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 8503 Comm: syz-executor608 Not tainted 5.10.0-rc6-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:bpf_common_lru_populate kernel/bpf/bpf_lru_list.c:569 [inline]
> RIP: 0010:bpf_lru_populate+0xd8/0x5e0 kernel/bpf/bpf_lru_list.c:614
> Code: 03 4d 01 e7 48 01 d8 48 89 4c 24 10 4d 89 fe 48 89 44 24 08 e8 99 23 eb ff 49 8d 7e 12 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <0f> b6 04 18 38 d0 7f 08 84 c0 0f 85 80 04 00 00 49 8d 7e 13 41 c6
> RSP: 0018:ffffc9000126fc20 EFLAGS: 00010202
> RAX: 1ffff9200471266c RBX: dffffc0000000000 RCX: ffffffff8184e3e2
> RDX: 0000000000000002 RSI: ffffffff8184e2e7 RDI: ffffc90023893362
> RBP: 00000000000000bc R08: 000000000000107c R09: 0000000000000000
> R10: 000000000000107c R11: 0000000000000000 R12: 0000000000000001
> R13: 000000000000107c R14: ffffc90023893350 R15: ffffc900234832f0
> FS:  0000000000fe0880(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffff5200471266c CR3: 000000001ba62000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  prealloc_init kernel/bpf/hashtab.c:319 [inline]
>  htab_map_alloc+0xf6e/0x1230 kernel/bpf/hashtab.c:507
>  find_and_alloc_map kernel/bpf/syscall.c:123 [inline]
>  map_create kernel/bpf/syscall.c:829 [inline]
>  __do_sys_bpf+0xa81/0x5170 kernel/bpf/syscall.c:4374
>  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x4402e9
> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 0f 83 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007ffe77af23b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004402e9
> RDX: 0000000000000040 RSI: 0000000020000000 RDI: 0d00000000000000
> RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
> R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000401af0
> R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000
> Modules linked in:
> CR2: fffff5200471266c
> ---[ end trace 4f3928bacde7b3ed ]---
> RIP: 0010:bpf_common_lru_populate kernel/bpf/bpf_lru_list.c:569 [inline]
> RIP: 0010:bpf_lru_populate+0xd8/0x5e0 kernel/bpf/bpf_lru_list.c:614
> Code: 03 4d 01 e7 48 01 d8 48 89 4c 24 10 4d 89 fe 48 89 44 24 08 e8 99 23 eb ff 49 8d 7e 12 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <0f> b6 04 18 38 d0 7f 08 84 c0 0f 85 80 04 00 00 49 8d 7e 13 41 c6
> RSP: 0018:ffffc9000126fc20 EFLAGS: 00010202
> RAX: 1ffff9200471266c RBX: dffffc0000000000 RCX: ffffffff8184e3e2
> RDX: 0000000000000002 RSI: ffffffff8184e2e7 RDI: ffffc90023893362
> RBP: 00000000000000bc R08: 000000000000107c R09: 0000000000000000
> R10: 000000000000107c R11: 0000000000000000 R12: 0000000000000001
> R13: 000000000000107c R14: ffffc90023893350 R15: ffffc900234832f0
> FS:  0000000000fe0880(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffff5200471266c CR3: 000000001ba62000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> 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 syzkaller@...glegroups.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
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
>
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