* [syzbot] usb-testing boot error: BUG: unable to handle kernel paging request in follow_page_mask
@ 2022-09-06 14:44 syzbot
2022-09-07 0:22 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2022-09-06 14:44 UTC (permalink / raw)
To: akpm, linux-kernel, linux-mm, linux-usb, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 4e55e22d3d9a USB: hcd-pci: Drop the unused id parameter fr..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=16b2d4d7080000
kernel config: https://syzkaller.appspot.com/x/.config?x=3cb39b084894e9a5
dashboard link: https://syzkaller.appspot.com/bug?extid=6b3a1fd733d73b7a14d7
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/05f931abacee/disk-4e55e22d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9b749a498398/vmlinux-4e55e22d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com
BUG: unable to handle page fault for address: ffffeefda00001ff
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 687 Comm: kworker/u4:0 Not tainted 6.0.0-rc1-syzkaller-00049-g4e55e22d3d9a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__get_user_pages+0x3f2/0x1020 mm/gup.c:1193
__get_user_pages_locked mm/gup.c:1399 [inline]
__get_user_pages_remote+0x18f/0x830 mm/gup.c:2109
get_user_pages_remote+0x84/0xc0 mm/gup.c:2182
get_arg_page+0xe4/0x2a0 fs/exec.c:222
copy_string_kernel+0x169/0x460 fs/exec.c:639
copy_strings_kernel+0xb3/0x190 fs/exec.c:655
kernel_execve+0x377/0x500 fs/exec.c:2001
call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Modules linked in:
CR2: ffffeefda00001ff
---[ end trace 0000000000000000 ]---
RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 80 88 ff ff 4c add %al,0x4cffff88(%rax)
6: 01 e8 add %ebp,%eax
8: 4d 89 e5 mov %r12,%r13
b: 49 c1 ed 1b shr $0x1b,%r13
f: 41 81 e5 f8 0f 00 00 and $0xff8,%r13d
16: 49 01 c5 add %rax,%r13
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 4c 89 ea mov %r13,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 d4 18 00 00 jne 0x1908
34: 4d 8b 75 00 mov 0x0(%r13),%r14
38: 31 ff xor %edi,%edi
3a: 49 83 e6 9f and $0xffffffffffffff9f,%r14
3e: 4c rex.WR
3f: 89 .byte 0x89
---
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@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] usb-testing boot error: BUG: unable to handle kernel paging request in follow_page_mask
2022-09-06 14:44 [syzbot] usb-testing boot error: BUG: unable to handle kernel paging request in follow_page_mask syzbot
@ 2022-09-07 0:22 ` Andrew Morton
2022-09-08 1:03 ` John Hubbard
0 siblings, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2022-09-07 0:22 UTC (permalink / raw)
To: syzbot
Cc: linux-kernel, linux-mm, linux-usb, syzkaller-bugs,
Jason Gunthorpe, John Hubbard, Alistair Popple, Ralph Campbell,
Alex Sierra, Dan Williams
(cc some of the gup.c developers)
On Tue, 06 Sep 2022 07:44:25 -0700 syzbot <syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 4e55e22d3d9a USB: hcd-pci: Drop the unused id parameter fr..
> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> console output: https://syzkaller.appspot.com/x/log.txt?x=16b2d4d7080000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3cb39b084894e9a5
> dashboard link: https://syzkaller.appspot.com/bug?extid=6b3a1fd733d73b7a14d7
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/05f931abacee/disk-4e55e22d.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/9b749a498398/vmlinux-4e55e22d.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com
>
> BUG: unable to handle page fault for address: ffffeefda00001ff
Thanks. A bit strange that it came from the USB tree, but I assume this
bug originates from Linus's current.
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 0 P4D 0
> Oops: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 687 Comm: kworker/u4:0 Not tainted 6.0.0-rc1-syzkaller-00049-g4e55e22d3d9a #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
> RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
> RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
> RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
> RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
> RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
> Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
> RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
> RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
> RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
> RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
> R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
> FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __get_user_pages+0x3f2/0x1020 mm/gup.c:1193
> __get_user_pages_locked mm/gup.c:1399 [inline]
> __get_user_pages_remote+0x18f/0x830 mm/gup.c:2109
> get_user_pages_remote+0x84/0xc0 mm/gup.c:2182
> get_arg_page+0xe4/0x2a0 fs/exec.c:222
> copy_string_kernel+0x169/0x460 fs/exec.c:639
> copy_strings_kernel+0xb3/0x190 fs/exec.c:655
> kernel_execve+0x377/0x500 fs/exec.c:2001
> call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
> </TASK>
> Modules linked in:
> CR2: ffffeefda00001ff
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
> RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
> RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
> RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
> RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
> Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
> RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
> RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
> RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
> RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
> R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
> FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
> 0: 00 80 88 ff ff 4c add %al,0x4cffff88(%rax)
> 6: 01 e8 add %ebp,%eax
> 8: 4d 89 e5 mov %r12,%r13
> b: 49 c1 ed 1b shr $0x1b,%r13
> f: 41 81 e5 f8 0f 00 00 and $0xff8,%r13d
> 16: 49 01 c5 add %rax,%r13
> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
> 20: fc ff df
> 23: 4c 89 ea mov %r13,%rdx
> 26: 48 c1 ea 03 shr $0x3,%rdx
> * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
> 2e: 0f 85 d4 18 00 00 jne 0x1908
> 34: 4d 8b 75 00 mov 0x0(%r13),%r14
> 38: 31 ff xor %edi,%edi
> 3a: 49 83 e6 9f and $0xffffffffffffff9f,%r14
> 3e: 4c rex.WR
> 3f: 89 .byte 0x89
>
>
> ---
> 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@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] usb-testing boot error: BUG: unable to handle kernel paging request in follow_page_mask
2022-09-07 0:22 ` Andrew Morton
@ 2022-09-08 1:03 ` John Hubbard
2022-09-08 13:36 ` Dmitry Vyukov
0 siblings, 1 reply; 4+ messages in thread
From: John Hubbard @ 2022-09-08 1:03 UTC (permalink / raw)
To: Andrew Morton, syzbot
Cc: linux-kernel, linux-mm, linux-usb, syzkaller-bugs,
Jason Gunthorpe, Alistair Popple, Ralph Campbell, Alex Sierra,
Dan Williams
On 9/6/22 17:22, Andrew Morton wrote:
>
> (cc some of the gup.c developers)
I wrote down some of the more obvious analysis results below, but I
don't have any insight into how this happened.
>
> On Tue, 06 Sep 2022 07:44:25 -0700 syzbot <syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com> wrote:
>
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: 4e55e22d3d9a USB: hcd-pci: Drop the unused id parameter fr..
>> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
>> console output: https://syzkaller.appspot.com/x/log.txt?x=16b2d4d7080000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=3cb39b084894e9a5
>> dashboard link: https://syzkaller.appspot.com/bug?extid=6b3a1fd733d73b7a14d7
>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/05f931abacee/disk-4e55e22d.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/9b749a498398/vmlinux-4e55e22d.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com
>>
>> BUG: unable to handle page fault for address: ffffeefda00001ff
>
> Thanks. A bit strange that it came from the USB tree, but I assume this
> bug originates from Linus's current.
>
>> #PF: supervisor read access in kernel mode
>> #PF: error_code(0x0000) - not-present page
>> PGD 0 P4D 0
>> Oops: 0000 [#1] PREEMPT SMP KASAN
>> CPU: 1 PID: 687 Comm: kworker/u4:0 Not tainted 6.0.0-rc1-syzkaller-00049-g4e55e22d3d9a #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
>> RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
>> RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
>> RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
Verified in the source code: this is crashing due to a bad address
in the pud pointer:
follow_pud_mask():
pud = pud_offset(p4dp, address);
if (pud_none(*pud)) // <-- crashes here
>> RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
>> RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
>> Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
>> RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
>> RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
>> RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
>> RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
>> R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
>> FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> __get_user_pages+0x3f2/0x1020 mm/gup.c:1193
>> __get_user_pages_locked mm/gup.c:1399 [inline]
>> __get_user_pages_remote+0x18f/0x830 mm/gup.c:2109
>> get_user_pages_remote+0x84/0xc0 mm/gup.c:2182
>> get_arg_page+0xe4/0x2a0 fs/exec.c:222
>> copy_string_kernel+0x169/0x460 fs/exec.c:639
>> copy_strings_kernel+0xb3/0x190 fs/exec.c:655
>> kernel_execve+0x377/0x500 fs/exec.c:2001
>> call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
>> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
>> </TASK>
>> Modules linked in:
>> CR2: ffffeefda00001ff
>> ---[ end trace 0000000000000000 ]---
>> RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
>> RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
>> RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
>> RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
>> RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
>> Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
>> RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
>> RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
>> RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
>> RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
>> R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
>> FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> ----------------
>> Code disassembly (best guess):
>> 0: 00 80 88 ff ff 4c add %al,0x4cffff88(%rax)
>> 6: 01 e8 add %ebp,%eax
>> 8: 4d 89 e5 mov %r12,%r13
>> b: 49 c1 ed 1b shr $0x1b,%r13
>> f: 41 81 e5 f8 0f 00 00 and $0xff8,%r13d
>> 16: 49 01 c5 add %rax,%r13
>> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
>> 20: fc ff df
>> 23: 4c 89 ea mov %r13,%rdx
>> 26: 48 c1 ea 03 shr $0x3,%rdx
>> * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
The fault address captured in CR2 (ffffeefda00001ff) matches what
is calculated in the above line:
%rdx + (%rax * 1):
1ffff2fda00001ff + dffffc0000000000 == ffffeefda00001ff
Note that this is an odd (as opposed to even) address, in fact it
ends with 511. This is never a valid pointer, but it does look like
a calculation gone wrong.
I'm short of ideas as to how this happened, though.
>> 2e: 0f 85 d4 18 00 00 jne 0x1908
>> 34: 4d 8b 75 00 mov 0x0(%r13),%r14
>> 38: 31 ff xor %edi,%edi
>> 3a: 49 83 e6 9f and $0xffffffffffffff9f,%r14
>> 3e: 4c rex.WR
>> 3f: 89 .byte 0x89
>>
>>
>> ---
>> 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@googlegroups.com.
>>
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
thanks,
--
John Hubbard
NVIDIA
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] usb-testing boot error: BUG: unable to handle kernel paging request in follow_page_mask
2022-09-08 1:03 ` John Hubbard
@ 2022-09-08 13:36 ` Dmitry Vyukov
0 siblings, 0 replies; 4+ messages in thread
From: Dmitry Vyukov @ 2022-09-08 13:36 UTC (permalink / raw)
To: John Hubbard
Cc: Andrew Morton, syzbot, linux-kernel, linux-mm, linux-usb,
syzkaller-bugs, Jason Gunthorpe, Alistair Popple, Ralph Campbell,
Alex Sierra, Dan Williams
On Thu, 8 Sept 2022 at 03:01, 'John Hubbard' via syzkaller-bugs
<syzkaller-bugs@googlegroups.com> wrote:
>
> On 9/6/22 17:22, Andrew Morton wrote:
> >
> > (cc some of the gup.c developers)
>
> I wrote down some of the more obvious analysis results below, but I
> don't have any insight into how this happened.
>
> >
> > On Tue, 06 Sep 2022 07:44:25 -0700 syzbot <syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com> wrote:
> >
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit: 4e55e22d3d9a USB: hcd-pci: Drop the unused id parameter fr..
> >> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=16b2d4d7080000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=3cb39b084894e9a5
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=6b3a1fd733d73b7a14d7
> >> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> >>
> >> Downloadable assets:
> >> disk image: https://storage.googleapis.com/syzbot-assets/05f931abacee/disk-4e55e22d.raw.xz
> >> vmlinux: https://storage.googleapis.com/syzbot-assets/9b749a498398/vmlinux-4e55e22d.xz
> >>
> >> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> Reported-by: syzbot+6b3a1fd733d73b7a14d7@syzkaller.appspotmail.com
> >>
> >> BUG: unable to handle page fault for address: ffffeefda00001ff
> >
> > Thanks. A bit strange that it came from the USB tree, but I assume this
> > bug originates from Linus's current.
> >
> >> #PF: supervisor read access in kernel mode
> >> #PF: error_code(0x0000) - not-present page
> >> PGD 0 P4D 0
> >> Oops: 0000 [#1] PREEMPT SMP KASAN
> >> CPU: 1 PID: 687 Comm: kworker/u4:0 Not tainted 6.0.0-rc1-syzkaller-00049-g4e55e22d3d9a #0
> >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
> >> RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
> >> RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
> >> RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
>
> Verified in the source code: this is crashing due to a bad address
> in the pud pointer:
>
> follow_pud_mask():
> pud = pud_offset(p4dp, address);
> if (pud_none(*pud)) // <-- crashes here
USB tree still misses "virtio: Revert "virtio: find_vqs() add arg
sizes"" commit.
W/o that revert there are assorted memory corruptions all over the kernel.
If you don't see anything obvious, I think we can safely say:
#syz fix: virtio: Revert "virtio: find_vqs() add arg sizes"
> >> RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
> >> RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
> >> Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
> >> RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
> >> RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
> >> RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
> >> RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
> >> R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
> >> R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
> >> FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
> >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >> Call Trace:
> >> <TASK>
> >> __get_user_pages+0x3f2/0x1020 mm/gup.c:1193
> >> __get_user_pages_locked mm/gup.c:1399 [inline]
> >> __get_user_pages_remote+0x18f/0x830 mm/gup.c:2109
> >> get_user_pages_remote+0x84/0xc0 mm/gup.c:2182
> >> get_arg_page+0xe4/0x2a0 fs/exec.c:222
> >> copy_string_kernel+0x169/0x460 fs/exec.c:639
> >> copy_strings_kernel+0xb3/0x190 fs/exec.c:655
> >> kernel_execve+0x377/0x500 fs/exec.c:2001
> >> call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
> >> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
> >> </TASK>
> >> Modules linked in:
> >> CR2: ffffeefda00001ff
> >> ---[ end trace 0000000000000000 ]---
> >> RIP: 0010:native_pud_val arch/x86/include/asm/pgtable_types.h:347 [inline]
> >> RIP: 0010:pud_none arch/x86/include/asm/pgtable.h:829 [inline]
> >> RIP: 0010:follow_pud_mask mm/gup.c:730 [inline]
> >> RIP: 0010:follow_p4d_mask mm/gup.c:782 [inline]
> >> RIP: 0010:follow_page_mask+0x1a9/0x1c90 mm/gup.c:846
> >> Code: 00 80 88 ff ff 4c 01 e8 4d 89 e5 49 c1 ed 1b 41 81 e5 f8 0f 00 00 49 01 c5 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 d4 18 00 00 4d 8b 75 00 31 ff 49 83 e6 9f 4c 89
> >> RSP: 0000:ffffc90001e7fb10 EFLAGS: 00010a06
> >> RAX: dffffc0000000000 RBX: ffff88810e732500 RCX: 0000000000000000
> >> RDX: 1ffff2fda00001ff RSI: ffffffff8167fdbd RDI: 0000000000000007
> >> RBP: ffffc90001e7fc48 R08: 0000000000000007 R09: 0000000000000000
> >> R10: 0000000000000000 R11: 0000000000000000 R12: 00007fffffffefc0
> >> R13: ffff97ed00000ff8 R14: 0000000000000000 R15: 0000000000002017
> >> FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
> >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: ffffeefda00001ff CR3: 0000000007825000 CR4: 00000000003506e0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >> ----------------
> >> Code disassembly (best guess):
> >> 0: 00 80 88 ff ff 4c add %al,0x4cffff88(%rax)
> >> 6: 01 e8 add %ebp,%eax
> >> 8: 4d 89 e5 mov %r12,%r13
> >> b: 49 c1 ed 1b shr $0x1b,%r13
> >> f: 41 81 e5 f8 0f 00 00 and $0xff8,%r13d
> >> 16: 49 01 c5 add %rax,%r13
> >> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
> >> 20: fc ff df
> >> 23: 4c 89 ea mov %r13,%rdx
> >> 26: 48 c1 ea 03 shr $0x3,%rdx
> >> * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
>
>
> The fault address captured in CR2 (ffffeefda00001ff) matches what
> is calculated in the above line:
>
> %rdx + (%rax * 1):
> 1ffff2fda00001ff + dffffc0000000000 == ffffeefda00001ff
>
> Note that this is an odd (as opposed to even) address, in fact it
> ends with 511. This is never a valid pointer, but it does look like
> a calculation gone wrong.
>
> I'm short of ideas as to how this happened, though.
>
> >> 2e: 0f 85 d4 18 00 00 jne 0x1908
> >> 34: 4d 8b 75 00 mov 0x0(%r13),%r14
> >> 38: 31 ff xor %edi,%edi
> >> 3a: 49 83 e6 9f and $0xffffffffffffff9f,%r14
> >> 3e: 4c rex.WR
> >> 3f: 89 .byte 0x89
> >>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-09-08 13:37 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-06 14:44 [syzbot] usb-testing boot error: BUG: unable to handle kernel paging request in follow_page_mask syzbot
2022-09-07 0:22 ` Andrew Morton
2022-09-08 1:03 ` John Hubbard
2022-09-08 13:36 ` Dmitry Vyukov
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