2023-11-02 15:27:06

by syzbot

[permalink] [raw]
Subject: [syzbot] [mm?] general protection fault in hugetlb_vma_lock_read

Hello,

syzbot found the following issue on:

HEAD commit: babe393974de Merge tag 'docs-6.7' of git://git.lwn.net/linux
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=176e7813680000
kernel config: https://syzkaller.appspot.com/x/.config?x=34994593e74fdcfe
dashboard link: https://syzkaller.appspot.com/bug?extid=93e7c679006f0d4e6105
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/81ff19e40c77/disk-babe3939.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a92e6d2d9507/vmlinux-babe3939.xz
kernel image: https://storage.googleapis.com/syzbot-assets/afd2bad18cfc/bzImage-babe3939.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'.
general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
CPU: 1 PID: 15736 Comm: syz-executor.1 Not tainted 6.6.0-syzkaller-10265-gbabe393974de #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5004
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 21 dc 81 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a e0 09 b3 90 0f 84 96 0d 00
RSP: 0018:ffffc90003387378 EFLAGS: 00010006
RAX: ffff88801d5e9dc0 RBX: 1ffff92000670e9f RCX: 000000000000001d
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 00000000000000e8
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 00000000000000e8 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS: 00007f07477fc6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000b80 CR3: 000000006a8b7000 CR4: 00000000003506f0
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5753 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
down_read+0x9c/0x470 kernel/locking/rwsem.c:1526
hugetlb_vma_lock_read mm/hugetlb.c:274 [inline]
hugetlb_vma_lock_read+0xae/0x100 mm/hugetlb.c:265
hugetlb_follow_page_mask+0x156/0xf20 mm/hugetlb.c:6500
follow_page_mask+0x49e/0xda0 mm/gup.c:824
__get_user_pages+0x366/0x1480 mm/gup.c:1237
__get_user_pages_locked mm/gup.c:1504 [inline]
__gup_longterm_locked+0x755/0x2570 mm/gup.c:2198
pin_user_pages_remote+0xee/0x140 mm/gup.c:3346
process_vm_rw_single_vec mm/process_vm_access.c:105 [inline]
process_vm_rw_core.constprop.0+0x43d/0xa10 mm/process_vm_access.c:215
process_vm_rw+0x2ff/0x360 mm/process_vm_access.c:283
__do_sys_process_vm_writev mm/process_vm_access.c:303 [inline]
__se_sys_process_vm_writev mm/process_vm_access.c:298 [inline]
__x64_sys_process_vm_writev+0xe2/0x1b0 mm/process_vm_access.c:298
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f0746a7cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f07477fc0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000137
RAX: ffffffffffffffda RBX: 00007f0746b9bf80 RCX: 00007f0746a7cae9
RDX: 0000000000000001 RSI: 0000000020000b80 RDI: 0000000000001d1b
RBP: 00007f0746ac847a R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020000f80 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f0746b9bf80 R15: 00007f0746cbfa48
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5004
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 21 dc 81 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a e0 09 b3 90 0f 84 96 0d 00
RSP: 0018:ffffc90003387378 EFLAGS: 00010006
RAX: ffff88801d5e9dc0 RBX: 1ffff92000670e9f RCX: 000000000000001d
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 00000000000000e8
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 00000000000000e8 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS: 00007f07477fc6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000b80 CR3: 000000006a8b7000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: 45 85 c9 test %r9d,%r9d
3: 0f 84 cc 0e 00 00 je 0xed5
9: 44 8b 05 21 dc 81 0b mov 0xb81dc21(%rip),%r8d # 0xb81dc31
10: 45 85 c0 test %r8d,%r8d
13: 0f 84 be 0d 00 00 je 0xdd7
19: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
20: fc ff df
23: 4c 89 d1 mov %r10,%rcx
26: 48 c1 e9 03 shr $0x3,%rcx
* 2a: 80 3c 11 00 cmpb $0x0,(%rcx,%rdx,1) <-- trapping instruction
2e: 0f 85 e8 40 00 00 jne 0x411c
34: 49 81 3a e0 09 b3 90 cmpq $0xffffffff90b309e0,(%r10)
3b: 0f .byte 0xf
3c: 84 .byte 0x84
3d: 96 xchg %eax,%esi
3e: 0d .byte 0xd


---
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2023-11-16 17:32:57

by Mike Kravetz

[permalink] [raw]
Subject: Re: [syzbot] [mm?] general protection fault in hugetlb_vma_lock_read

On 11/16/23 15:53, xingwei lee wrote:
> Hello, since I found there is no reproduce from then to now. I try to
> reproduce this bug to generate repro.c.
> Maybe this bug is the same bug as [syzbot] [mm?] general protection fault
> in hugetlb_vma_lock_write I guess...
> But no matter what, with the reproduce.c, we can quickly fix this bug or
> check the correctness of our fix.

I am not sure what fix you suggested for this issue. The following was
sent upstream and is now included in Andrew's tree and linux-next.

https://lore.kernel.org/linux-mm/[email protected]/

I tested with a reproducer previously provided by syzbot, and assume this
resolves the issue with your reproducer as well.
--
Mike Kravetz