Re: [syzbot] [mm?] general protection fault in dequeue_hugetlb_folio_nodemask

From: Mario Limonciello
Date: Thu Jun 06 2024 - 11:16:31 EST

On 6/6/2024 09:39, syzbot wrote:
Hello,

syzbot found the following issue on:

HEAD commit: 0e1980c40b6e Add linux-next specific files for 20240531
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=166086f2980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d9c3ca4e54577b88
dashboard link: https://syzkaller.appspot.com/bug?extid=c019f68a83ef9b456444
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12f4094a980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15e1e432980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/44fb1d8b5978/disk-0e1980c4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a66ce5caf0b2/vmlinux-0e1980c4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8992fc8fe046/bzImage-0e1980c4.xz

The issue was bisected to:

commit cd94d1b182d2986378550c9087571991bfee01d4
Author: Mario Limonciello <mario.limonciello@xxxxxxx>
Date: Thu May 2 18:32:17 2024 +0000

dm/amd/pm: Fix problems with reboot/shutdown for some SMU 13.0.4/13.0.11 users

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=176121c2980000
console output: https://syzkaller.appspot.com/x/log.txt?x=10e121c2980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c019f68a83ef9b456444@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: cd94d1b182d2 ("dm/amd/pm: Fix problems with reboot/shutdown for some SMU 13.0.4/13.0.11 users")

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000489: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000000002448-0x000000000000244f]
CPU: 1 PID: 5089 Comm: syz-executor257 Not tainted 6.10.0-rc1-next-20240531-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:zonelist_zone_idx include/linux/mmzone.h:1613 [inline]
RIP: 0010:next_zones_zonelist include/linux/mmzone.h:1644 [inline]
RIP: 0010:first_zones_zonelist include/linux/mmzone.h:1670 [inline]
RIP: 0010:dequeue_hugetlb_folio_nodemask+0x193/0xe40 mm/hugetlb.c:1362
Code: 13 9b a0 ff c7 44 24 14 00 00 00 00 83 7c 24 40 00 0f 85 97 0c 00 00 48 83 7c 24 20 00 0f 85 45 09 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 58 09 00 00 44 8b 33 44 89 f7 8b 5c 24
RSP: 0018:ffffc900035ef720 EFLAGS: 00010002
RAX: 0000000000000489 RBX: 0000000000002448 RCX: ffff888026ef0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900035ef858 R08: ffffffff81f5e070 R09: fffff520006bdee8
R10: dffffc0000000000 R11: fffff520006bdee8 R12: 00000000ffffffff
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000555564010380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005fdeb8 CR3: 000000007bd96000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
alloc_hugetlb_folio_nodemask+0xae/0x3f0 mm/hugetlb.c:2603
memfd_alloc_folio+0x15e/0x390 mm/memfd.c:75
memfd_pin_folios+0x1066/0x1720 mm/gup.c:3864
udmabuf_create+0x658/0x11c0 drivers/dma-buf/udmabuf.c:353
udmabuf_ioctl_create drivers/dma-buf/udmabuf.c:420 [inline]
udmabuf_ioctl+0x304/0x4f0 drivers/dma-buf/udmabuf.c:451
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5151a7a369
Code: 48 83 c4 28 c3 e8 37 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd962ee9e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffd962eebb8 RCX: 00007f5151a7a369
RDX: 00000000200002c0 RSI: 0000000040187542 RDI: 0000000000000003
RBP: 00007f5151aed610 R08: 00007ffd962eebb8 R09: 00007ffd962eebb8
R10: 00007ffd962eebb8 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd962eeba8 R14: 0000000000000001 R15: 0000000000000001
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:zonelist_zone_idx include/linux/mmzone.h:1613 [inline]
RIP: 0010:next_zones_zonelist include/linux/mmzone.h:1644 [inline]
RIP: 0010:first_zones_zonelist include/linux/mmzone.h:1670 [inline]
RIP: 0010:dequeue_hugetlb_folio_nodemask+0x193/0xe40 mm/hugetlb.c:1362
Code: 13 9b a0 ff c7 44 24 14 00 00 00 00 83 7c 24 40 00 0f 85 97 0c 00 00 48 83 7c 24 20 00 0f 85 45 09 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 58 09 00 00 44 8b 33 44 89 f7 8b 5c 24
RSP: 0018:ffffc900035ef720 EFLAGS: 00010002
RAX: 0000000000000489 RBX: 0000000000002448 RCX: ffff888026ef0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900035ef858 R08: ffffffff81f5e070 R09: fffff520006bdee8
R10: dffffc0000000000 R11: fffff520006bdee8 R12: 00000000ffffffff
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000555564010380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005fdeb8 CR3: 000000007bd96000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 13 9b a0 ff c7 44 adc 0x44c7ffa0(%rbx),%ebx
6: 24 14 and $0x14,%al
8: 00 00 add %al,(%rax)
a: 00 00 add %al,(%rax)
c: 83 7c 24 40 00 cmpl $0x0,0x40(%rsp)
11: 0f 85 97 0c 00 00 jne 0xcae
17: 48 83 7c 24 20 00 cmpq $0x0,0x20(%rsp)
1d: 0f 85 45 09 00 00 jne 0x968
23: 48 89 d8 mov %rbx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 58 09 00 00 jne 0x98f
37: 44 8b 33 mov (%rbx),%r14d
3a: 44 89 f7 mov %r14d,%edi
3d: 8b .byte 0x8b
3e: 5c pop %rsp
3f: 24 .byte 0x24


---
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I don't believe the bot did this right. Running in a VM outside of shutdown won't exercise this codepath.

#syz invalid

But FWIW there WAS a different problem with that commit which will be fixed with:

https://gitlab.freedesktop.org/agd5f/linux/-/commit/2541609cd583dd13bf809934806df141e123d35f

Alex, I don't see this in the 6.10 fixes branch, could you pull it in an upcoming one?