Re: general protection fault in ip6_dst_lookup_tail (2)

[Dmitry Vyukov]

On Mon, Apr 29, 2019 at 8:51 AM syzbot
<syzbot+58d8f704b86e4e3fb4d3@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    fdfdf867 net: phy: marvell: Fix buffer overrun with stats ..
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=12be0d38a00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a42d110b47dd6b36
> dashboard link: https://syzkaller.appspot.com/bug?extid=58d8f704b86e4e3fb4d3
> 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: syzbot+58d8f704b86e4e3fb4d3@xxxxxxxxxxxxxxxxxxxxxxxxx

Eric, can this be fixed by your "ipv6: fix races in ip6_dst_destroy()"?
https://patchwork.ozlabs.org/patch/1092328/


> 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
> CPU: 1 PID: 20190 Comm: syz-executor.0 Not tainted 5.1.0-rc6+ #184
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:ip6_route_get_saddr include/net/ip6_route.h:119 [inline]
> RIP: 0010:ip6_dst_lookup_tail+0xf0e/0x1b30 net/ipv6/ip6_output.c:971
> Code: e6 07 e8 55 57 61 fb 48 85 db 0f 84 83 08 00 00 e8 47 57 61 fb 48 8d
> 7b 7c 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48
> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 07
> RSP: 0018:ffff888063406f40 EFLAGS: 00010207
> RAX: dffffc0000000000 RBX: 00c0200001ffff88 RCX: ffffc90005fe4000
> RDX: 0018040000400000 RSI: ffffffff860f35a9 RDI: 00c0200002000004
> RBP: ffff888063407098 R08: ffff888085a7c000 R09: ffffed1015d25bc8
> R10: ffffed1015d25bc7 R11: ffff8880ae92de3b R12: ffff8880653b3270
> R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880653b3298
> FS:  00007f58b1851700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000001fc96f0 CR3: 000000006d91d000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>   ip6_dst_lookup_flow+0xa8/0x220 net/ipv6/ip6_output.c:1094
>   sctp_v6_get_dst+0x785/0x1d80 net/sctp/ipv6.c:293
>   sctp_transport_route+0x132/0x370 net/sctp/transport.c:312
>   sctp_assoc_add_peer+0x53e/0xfc0 net/sctp/associola.c:678
>   sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline]
>   sctp_process_init+0x249f/0x2b20 net/sctp/sm_make_chunk.c:2361
>   sctp_sf_do_unexpected_init net/sctp/sm_statefuns.c:1556 [inline]
>   sctp_sf_do_unexpected_init.isra.0+0x7cd/0x1350 net/sctp/sm_statefuns.c:1456
>   sctp_sf_do_5_2_1_siminit+0x35/0x40 net/sctp/sm_statefuns.c:1685
>   sctp_do_sm+0x12c/0x5770 net/sctp/sm_sideeffect.c:1188
>   sctp_assoc_bh_rcv+0x343/0x660 net/sctp/associola.c:1074
>   sctp_inq_push+0x1ea/0x290 net/sctp/inqueue.c:95
>   sctp_backlog_rcv+0x196/0xbe0 net/sctp/input.c:354
>   sk_backlog_rcv include/net/sock.h:943 [inline]
>   __release_sock+0x12e/0x3a0 net/core/sock.c:2413
>   release_sock+0x59/0x1c0 net/core/sock.c:2929
>   sctp_wait_for_connect+0x316/0x540 net/sctp/socket.c:9048
>   __sctp_connect+0xac2/0xce0 net/sctp/socket.c:1241
>   sctp_connect net/sctp/socket.c:4858 [inline]
>   sctp_inet_connect+0x2a2/0x340 net/sctp/socket.c:4874
>   __sys_connect+0x266/0x330 net/socket.c:1808
>   __do_sys_connect net/socket.c:1819 [inline]
>   __se_sys_connect net/socket.c:1816 [inline]
>   __x64_sys_connect+0x73/0xb0 net/socket.c:1816
>   do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x458da9
> Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f58b1850c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458da9
> RDX: 000000000000001c RSI: 0000000020000200 RDI: 0000000000000003
> RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f58b18516d4
> R13: 00000000004bf1f1 R14: 00000000004d02c0 R15: 00000000ffffffff
> Modules linked in:
> ---[ end trace 04c26bfcf25dca59 ]---
> RIP: 0010:ip6_route_get_saddr include/net/ip6_route.h:119 [inline]
> RIP: 0010:ip6_dst_lookup_tail+0xf0e/0x1b30 net/ipv6/ip6_output.c:971
> Code: e6 07 e8 55 57 61 fb 48 85 db 0f 84 83 08 00 00 e8 47 57 61 fb 48 8d
> 7b 7c 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48
> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 07
> RSP: 0018:ffff888063406f40 EFLAGS: 00010207
> RAX: dffffc0000000000 RBX: 00c0200001ffff88 RCX: ffffc90005fe4000
> RDX: 0018040000400000 RSI: ffffffff860f35a9 RDI: 00c0200002000004
> RBP: ffff888063407098 R08: ffff888085a7c000 R09: ffffed1015d25bc8
> R10: ffffed1015d25bc7 R11: ffff8880ae92de3b R12: ffff8880653b3270
> R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880653b3298
> FS:  00007f58b1851700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000000070c09b CR3: 000000006d91d000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> This bug is generated by a bot. It may contain errors.
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