Re: general protection fault in io_disable_sqo_submit

[Pavel Begunkov <asml.silence@gmail.com>]

On 14/01/2021 07:40, Hillf Danton wrote:
> Wed, 13 Jan 2021 02:37:15 -0800
>> syzbot found the following issue on:
>>
>> HEAD commit:    7c53f6b6 Linux 5.11-rc3
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1606a757500000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=c60c9ff9cc916cbc
>> dashboard link: https://syzkaller.appspot.com/bug?extid=ab412638aeb652ded540
>> compiler:       gcc (GCC) 10.1.0-syz 20200507
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13adb0d0d00000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1527be48d00000
>>
>> The issue was bisected to:
>>
>> commit d9d05217cb6990b9a56e13b56e7a1b71e2551f6c
>> Author: Pavel Begunkov <asml.silence@gmail.com>
>> Date:   Fri Jan 8 20:57:25 2021 +0000
>>
>>     io_uring: stop SQPOLL submit on creator's death
>>
>> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17b3b248d00000
>> final oops:     https://syzkaller.appspot.com/x/report.txt?x=1473b248d00000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1073b248d00000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+ab412638aeb652ded540@syzkaller.appspotmail.com
>> Fixes: d9d05217cb69 ("io_uring: stop SQPOLL submit on creator's death")
>>
>> RDX: 0000000000000001 RSI: 0000000020000300 RDI: 00000000000000ff
>> RBP: 0000000000011fc2 R08: 0000000000000001 R09: 00000000004002c8
>> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004021d0
>> R13: 0000000000402260 R14: 0000000000000000 R15: 0000000000000000
>> general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] PREEMPT SMP KASAN
>> KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117]
>> CPU: 1 PID: 8473 Comm: syz-executor814 Not tainted 5.11.0-rc3-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>> RIP: 0010:io_ring_set_wakeup_flag fs/io_uring.c:6929 [inline]
>> RIP: 0010:io_disable_sqo_submit+0xdb/0x130 fs/io_uring.c:8891
>> Code: fa 48 c1 ea 03 80 3c 02 00 75 62 48 8b 9b c0 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 14 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1d 83
>> RSP: 0018:ffffc9000154fd78 EFLAGS: 00010007
>> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff815976e0
>> RDX: 0000000000000022 RSI: 0000000000000004 RDI: 0000000000000114
>> RBP: ffff8880149ee480 R08: 0000000000000001 R09: 0000000000000003
>> R10: fffff520002a9fa1 R11: 1ffffffff1d308df R12: fffffffffffffff4
>> R13: 0000000000000001 R14: ffff8880149ee054 R15: ffff8880149ee000
>> FS:  0000000000be4880(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000020000304 CR3: 0000000014b50000 CR4: 00000000001506e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>>  io_uring_create fs/io_uring.c:9711 [inline]
>>  io_uring_setup+0x12b1/0x38e0 fs/io_uring.c:9739
>>  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> RIP: 0033:0x441309
>> Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 3b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
>> RSP: 002b:00007ffea5e64578 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441309
>> RDX: 0000000000000001 RSI: 0000000020000300 RDI: 00000000000000ff
>> RBP: 0000000000011fc2 R08: 0000000000000001 R09: 00000000004002c8
>> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004021d0
>> R13: 0000000000402260 R14: 0000000000000000 R15: 0000000000000000
>> Modules linked in:
>> ---[ end trace 0941172fec2041bb ]---
>> RIP: 0010:io_ring_set_wakeup_flag fs/io_uring.c:6929 [inline]
>> RIP: 0010:io_disable_sqo_submit+0xdb/0x130 fs/io_uring.c:8891
>> Code: fa 48 c1 ea 03 80 3c 02 00 75 62 48 8b 9b c0 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 14 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1d 83
>> RSP: 0018:ffffc9000154fd78 EFLAGS: 00010007
>> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff815976e0
>> RDX: 0000000000000022 RSI: 0000000000000004 RDI: 0000000000000114
>> RBP: ffff8880149ee480 R08: 0000000000000001 R09: 0000000000000003
>> R10: fffff520002a9fa1 R11: 1ffffffff1d308df R12: fffffffffffffff4
>> R13: 0000000000000001 R14: ffff8880149ee054 R15: ffff8880149ee000
>> FS:  0000000000be4880(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000020000304 CR3: 0000000014b50000 CR4: 00000000001506e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> 
> Fix d9d05217cb69 ("io_uring: stop SQPOLL submit on creator's death")
> by setting ctx->sqo_dead as part of cleanup in case of failing to
> create io uring context, to quiesce the warning added in the commit.

Thanks, but it was fixed the day before

-- 
Pavel Begunkov