Re: general protection fault in unlink_file_vma

[linmiaohe]

>
>Hello,
>
>syzbot has tested the proposed patch but the reproducer is still triggering an issue:
>kernel BUG at arch/x86/mm/physaddr.c:LINE!
>
>------------[ cut here ]------------
>kernel BUG at arch/x86/mm/physaddr.c:28!
>invalid opcode: 0000 [#1] PREEMPT SMP KASAN
>CPU: 0 PID: 6975 Comm: syz-executor.2 Not tainted 5.9.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>RIP: 0010:__phys_addr+0xa7/0x110 arch/x86/mm/physaddr.c:28
>Code: 92 7d 09 4c 89 e3 31 ff 48 d3 eb 48 89 de e8 10 8e 3f 00 48 85 db 75 0d e8 66 91 3f 00 4c 89 e0 5b 5d 41 5c c3 e8 59 91 3f 00 <0f> 0b e8 52 91 3f 00 48 c7 c0 10 50 a9 89 48 ba 00 00 00 00 00 fc
>RSP: 0018:ffffc900055e7a18 EFLAGS: 00010293
>RAX: 0000000000000000 RBX: 0000007700000000 RCX: ffffffff8134b948
>RDX: ffff8880a83c8280 RSI: ffffffff8134b9a7 RDI: 0000000000000006
>RBP: 0000007780000000 R08: 0000000000000001 R09: ffffffff8c5f4a57
>R10: 0000007780000000 R11: 0000000000000000 R12: 000077f700000000
>R13: ffffc900055e7a80 R14: 0000000000000200 R15: dffffc0000000000
>FS:  000000000221c940(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
>CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>CR2: 0000000000749198 CR3: 00000000a7df1000 CR4: 00000000001506f0
>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace:
> virt_to_head_page include/linux/mm.h:848 [inline]  qlink_to_cache mm/kasan/quarantine.c:128 [inline]
> qlist_free_all+0xd9/0x170 mm/kasan/quarantine.c:165
> quarantine_reduce+0x17e/0x200 mm/kasan/quarantine.c:261
> __kasan_kmalloc.constprop.0+0x9e/0xd0 mm/kasan/common.c:442  slab_post_alloc_hook mm/slab.h:518 [inline]  slab_alloc_node mm/slab.c:3254 [inline]
> kmem_cache_alloc_node_trace+0x144/0x3f0 mm/slab.c:3592  kmalloc_node include/linux/slab.h:572 [inline]  kzalloc_node include/linux/slab.h:677 [inline]
> __get_vm_area_node+0x126/0x3b0 mm/vmalloc.c:2075  __vmalloc_node_range mm/vmalloc.c:2506 [inline]  __vmalloc_node mm/vmalloc.c:2554 [inline]
> vzalloc+0xf2/0x1a0 mm/vmalloc.c:2607
> do_ipt_get_ctl+0x613/0x9d0 net/ipv4/netfilter/ip_tables.c:800
> nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:116  ip_getsockopt net/ipv4/ip_sockglue.c:1778 [inline]
> ip_getsockopt+0x164/0x1c0 net/ipv4/ip_sockglue.c:1757
> tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:3876
> __sys_getsockopt+0x219/0x4c0 net/socket.c:2173  __do_sys_getsockopt net/socket.c:2188 [inline]  __se_sys_getsockopt net/socket.c:2185 [inline]
> __x64_sys_getsockopt+0xba/0x150 net/socket.c:2185
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>RIP: 0033:0x4600ca
>Code: b8 34 01 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 3d 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 1a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
>RSP: 002b:00007fff61ca7778 EFLAGS: 00000216 ORIG_RAX: 0000000000000037
>RAX: ffffffffffffffda RBX: 00007fff61ca77a0 RCX: 00000000004600ca
>RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003
>RBP: 0000000000749e60 R08: 00007fff61ca779c R09: 0000000000004000
>R10: 00007fff61ca7800 R11: 0000000000000216 R12: 00007fff61ca7800
>R13: 0000000000000003 R14: 00000000007497a0 R15: 0000000000000000 Modules linked in:
>---[ end trace 58c08b00b19487d8 ]---
>RIP: 0010:__phys_addr+0xa7/0x110 arch/x86/mm/physaddr.c:28
>Code: 92 7d 09 4c 89 e3 31 ff 48 d3 eb 48 89 de e8 10 8e 3f 00 48 85 db 75 0d e8 66 91 3f 00 4c 89 e0 5b 5d 41 5c c3 e8 59 91 3f 00 <0f> 0b e8 52 91 3f 00 48 c7 c0 10 50 a9 89 48 ba 00 00 00 00 00 fc
>RSP: 0018:ffffc900055e7a18 EFLAGS: 00010293
>RAX: 0000000000000000 RBX: 0000007700000000 RCX: ffffffff8134b948
>RDX: ffff8880a83c8280 RSI: ffffffff8134b9a7 RDI: 0000000000000006
>RBP: 0000007780000000 R08: 0000000000000001 R09: ffffffff8c5f4a57
>R10: 0000007780000000 R11: 0000000000000000 R12: 000077f700000000
>R13: ffffc900055e7a80 R14: 0000000000000200 R15: dffffc0000000000
>FS:  000000000221c940(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
>CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>CR2: 0000000000749198 CR3: 00000000a7df1000 CR4: 00000000001506f0
>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
>Tested on:
>
>commit:         152d246f mmap: revert mm-mmap-merge-vma-after-call_mmap-if..
>git tree:       https://github.com/Linmiaohe/linux vma_merge_fix
>console output: https://syzkaller.appspot.com/x/log.txt?x=162e6cc5900000
>kernel config:  https://syzkaller.appspot.com/x/.config?x=3c5f6ce8d5b68299
>dashboard link: https://syzkaller.appspot.com/bug?extid=c5d5a51dcbb558ca0cb5
>compiler:       gcc (GCC) 10.1.0-syz 20200507
>

I revert my previous commit altogether, d70cec8983241a ("mm: mmap: merge vma after call_mmap() if possible "), but there is still irrelevant issue.
And with my previous commit and proposed patch, the origin general protection fault in unlink_file_vma disappeared.
So I think this is another issue and the origin issue is fixed with my patch.
Thanks.