Re: [syzbot] [ntfs3?] general protection fault in ni_readpage_cmpr

syzbot
2023-05-07T10:30:45Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 14f8db1c0f9a Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=14ecc3b0280000
kernel config: https://syzkaller.appspot.com/x/.config?x=a837a8ba7e88bb45
dashboard link: https://syzkaller.appspot.com/bug?extid=af224b63e76b2d869bc3
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168ce182280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1308c522280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ad6ce516eed3/disk-14f8db1c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1f38c2cc7667/vmlinux-14f8db1c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d795115eee39/Image-14f8db1c.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/8a3eac658458/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+af224b63e76b2d869bc3@syzkaller.appspotmail.com

__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
Unable to handle kernel paging request at virtual address dfff800000000001
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[dfff800000000001] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5930 Comm: syz-executor385 Not tainted 6.3.0-rc7-syzkaller-g14f8db1c0f9a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : _compound_head include/linux/page-flags.h:251 [inline]
pc : unlock_page+0x28/0x74 mm/folio-compat.c:21
lr : unlock_page+0x18/0x74 mm/folio-compat.c:20
sp : ffff80001e4d6fa0
x29: ffff80001e4d6fa0 x28: 0000000000000007 x27: 00000000fffffff4
x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
x23: ffff0000d9371208 x22: 0000000000000001 x21: dfff800000000000
x20: 0000000000000008 x19: 0000000000000000 x18: 1fffe0003684a5b6
x17: 0000000000000000 x16: ffff8000084fa124 x15: 0000000000000001
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000001
x8 : dfff800000000000 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80001e4d61d8 x4 : ffff800015e4ccc0 x3 : ffff80000968c944
x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
_compound_head include/linux/page-flags.h:251 [inline]
unlock_page+0x28/0x74 mm/folio-compat.c:21
ni_readpage_cmpr+0x474/0x798 fs/ntfs3/frecord.c:2149
ntfs_read_folio+0x14c/0x1c0 fs/ntfs3/inode.c:703
filemap_read_folio+0x14c/0x39c mm/filemap.c:2424
filemap_create_folio mm/filemap.c:2552 [inline]
filemap_get_pages+0xb3c/0x1640 mm/filemap.c:2605
filemap_read+0x354/0xc98 mm/filemap.c:2693
generic_file_read_iter+0xa0/0x450 mm/filemap.c:2840
ntfs_file_read_iter+0x184/0x1e0 fs/ntfs3/file.c:758
call_read_iter include/linux/fs.h:1845 [inline]
generic_file_splice_read+0x1e0/0x508 fs/splice.c:402
do_splice_to fs/splice.c:885 [inline]
splice_direct_to_actor+0x30c/0x944 fs/splice.c:956
do_splice_direct+0x1f4/0x334 fs/splice.c:1065
do_sendfile+0x4bc/0xc70 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__arm64_sys_sendfile64+0x160/0x3b4 fs/read_write.c:1309
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
Code: d2d00008 91002274 f2fbffe8 d343fe89 (38686928)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: d2d00008 mov x8, #0x800000000000 // #140737488355328
4: 91002274 add x20, x19, #0x8
8: f2fbffe8 movk x8, #0xdfff, lsl #48
c: d343fe89 lsr x9, x20, #3
* 10: 38686928 ldrb w8, [x9, x8] <-- trapping instruction

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