[syzbot] BUG: unable to handle kernel paging request in folio_flags

syzbot
2023-02-08T20:19:56Z

Hello,

syzbot found the following issue on:

HEAD commit: 38d2b86a665b Add linux-next specific files for 20230208
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=147599df480000
kernel config: https://syzkaller.appspot.com/x/.config?x=3691b32dd4410e01
dashboard link: https://syzkaller.appspot.com/bug?extid=d632e24db18585d7b3c6
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0a9d60e90514/disk-38d2b86a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/71311be5f1a1/vmlinux-38d2b86a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a242870cc8eb/bzImage-38d2b86a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d632e24db18585d7b3c6@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffffffffffffed
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD c570067 P4D c570067 PUD c572067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5544 Comm: syz-executor.2 Not tainted 6.2.0-rc7-next-20230208-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:PageTail include/linux/page-flags.h:290 [inline]
RIP: 0010:folio_flags.constprop.0+0x2c/0x150 include/linux/page-flags.h:317
Code: 49 89 fc 55 53 e8 84 4e b7 ff 49 8d 7c 24 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f8 00 00 00 <49> 8b 5c 24 08 31 ff 83 e3 01 48 89 de e8 c2 4a b7 ff 48 85 db 0f
RSP: 0018:ffffc9000675fc08 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffffffffffe5 RCX: ffffc9000cd62000
RDX: 1ffffffffffffffd RSI: ffffffff81cd1f5c RDI: ffffffffffffffed
RBP: ffffffffffffffe5 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffe5 R11: 0000000000000000 R12: ffffffffffffffe5
R13: 000feffffff00000 R14: 0000000000000046 R15: 000feffffff00000
FS: 00007f6f37eb3700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffed CR3: 00000000217a0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
folio_test_head include/linux/page-flags.h:781 [inline]
folio_test_large include/linux/page-flags.h:802 [inline]
PageHeadHuge+0x18/0xc0 mm/hugetlb.c:2060
folio_test_hugetlb include/linux/page-flags.h:830 [inline]
folio_file_page include/linux/pagemap.h:702 [inline]
shmem_read_mapping_page_gfp+0x34/0x100 mm/shmem.c:4366
shmem_read_mapping_page include/linux/shmem_fs.h:124 [inline]
udmabuf_create+0x93b/0x1440 drivers/dma-buf/udmabuf.c:286
udmabuf_ioctl_create drivers/dma-buf/udmabuf.c:346 [inline]
udmabuf_ioctl+0x156/0x2c0 drivers/dma-buf/udmabuf.c:377
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6f3708c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6f37eb3168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6f371abf80 RCX: 00007f6f3708c0f9
RDX: 0000000020000080 RSI: 0000000040187542 RDI: 0000000000000005
RBP: 00007f6f370e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffec3da43f R14: 00007f6f37eb3300 R15: 0000000000022000
</TASK>
Modules linked in:
CR2: ffffffffffffffed
---[ end trace 0000000000000000 ]---
RIP: 0010:PageTail include/linux/page-flags.h:290 [inline]
RIP: 0010:folio_flags.constprop.0+0x2c/0x150 include/linux/page-flags.h:317
Code: 49 89 fc 55 53 e8 84 4e b7 ff 49 8d 7c 24 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f8 00 00 00 <49> 8b 5c 24 08 31 ff 83 e3 01 48 89 de e8 c2 4a b7 ff 48 85 db 0f
RSP: 0018:ffffc9000675fc08 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffffffffffe5 RCX: ffffc9000cd62000
RDX: 1ffffffffffffffd RSI: ffffffff81cd1f5c RDI: ffffffffffffffed
RBP: ffffffffffffffe5 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffe5 R11: 0000000000000000 R12: ffffffffffffffe5
R13: 000feffffff00000 R14: 0000000000000046 R15: 000feffffff00000
FS: 00007f6f37eb3700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffed CR3: 00000000217a0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 49 89 fc mov %rdi,%r12
3: 55 push %rbp
4: 53 push %rbx
5: e8 84 4e b7 ff callq 0xffb74e8e
a: 49 8d 7c 24 08 lea 0x8(%r12),%rdi
f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
16: fc ff df
19: 48 89 fa mov %rdi,%rdx
1c: 48 c1 ea 03 shr $0x3,%rdx
20: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
24: 0f 85 f8 00 00 00 jne 0x122
* 2a: 49 8b 5c 24 08 mov 0x8(%r12),%rbx <-- trapping instruction
2f: 31 ff xor %edi,%edi
31: 83 e3 01 and $0x1,%ebx
34: 48 89 de mov %rbx,%rsi
37: e8 c2 4a b7 ff callq 0xffb74afe
3c: 48 85 db test %rbx,%rbx
3f: 0f .byte 0xf

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