[syzbot] [udf?] WARNING in __udf_add_aext (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 64569520920a Merge tag 'block-6.4-2023-06-09' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=115adb1b280000
kernel config: https://syzkaller.appspot.com/x/.config?x=7474de833c217bf4
dashboard link: https://syzkaller.appspot.com/bug?extid=e381e4c52ca8a53c3af7
compiler: Debian clang version 15.0.7, 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/3239cb3f0553/disk-64569520.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d90e42dca619/vmlinux-64569520.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e0f88764a9f6/bzImage-64569520.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e381e4...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 26092 at fs/udf/inode.c:2050 __udf_add_aext+0x550/0x6f0
Modules linked in:
CPU: 1 PID: 26092 Comm: syz-executor.1 Not tainted 6.4.0-rc5-syzkaller-00245-g64569520920a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:__udf_add_aext+0x550/0x6f0 fs/udf/inode.c:2049
Code: 4c 89 e7 e8 22 d9 e3 fe 49 8b 3c 24 4c 89 fe e8 06 c5 03 ff 31 c0 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 f0 01 8c fe <0f> 0b e9 ed fb ff ff e8 e4 01 8c fe 0f 0b e9 5c fc ff ff e8 d8 01
RSP: 0018:ffffc900170d6b38 EFLAGS: 00010287
RAX: ffffffff82ff7db0 RBX: 1ffff92002e1ae01 RCX: 0000000000040000
RDX: ffffc90003d61000 RSI: 00000000000109da RDI: 00000000000109db
RBP: 0000000000000000 R08: ffffffff82ff7996 R09: ffffffff82ff78c6
R10: 0000000000000002 R11: ffff88807e450000 R12: ffffc900170d7000
R13: 0000000000000004 R14: dffffc0000000000 R15: ffffc900170d7008
FS: 00007f18bf12b700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200a0000 CR3: 0000000028a6f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
udf_add_aext fs/udf/inode.c:2107 [inline]
udf_do_extend_file+0xcb5/0x11e0 fs/udf/inode.c:592
inode_getblk fs/udf/inode.c:822 [inline]
udf_map_block+0x16c0/0x4ff0 fs/udf/inode.c:450
__udf_get_block+0x126/0x410 fs/udf/inode.c:464
__block_write_begin_int+0x548/0x1a50 fs/buffer.c:2064
udf_page_mkwrite+0x5b0/0x960 fs/udf/file.c:69
do_page_mkwrite+0x1a4/0x600 mm/memory.c:2931
wp_page_shared mm/memory.c:3280 [inline]
do_wp_page+0x501/0x3690 mm/memory.c:3362
handle_pte_fault mm/memory.c:4964 [inline]
__handle_mm_fault mm/memory.c:5089 [inline]
handle_mm_fault+0x2371/0x5860 mm/memory.c:5243
do_user_addr_fault arch/x86/mm/fault.c:1440 [inline]
handle_page_fault arch/x86/mm/fault.c:1534 [inline]
exc_page_fault+0x7d2/0x910 arch/x86/mm/fault.c:1590
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0010:rep_stos_alternative+0x40/0x80 arch/x86/lib/clear_page_64.S:96
Code: ff c7 48 ff c9 75 f6 c3 48 89 07 48 83 c7 08 83 e9 08 74 f3 83 f9 08 73 ef eb e2 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <48> 89 07 48 89 47 08 48 89 47 10 48 89 47 18 48 89 47 20 48 89 47
RSP: 0018:ffffc900170d7af8 EFLAGS: 00050202
RAX: 0000000000000000 RBX: 00000000200a0080 RCX: 0000000000000080
RDX: 0000000000000000 RSI: ffffffff8aea9fa0 RDI: 00000000200a0000
RBP: ffffc900170d7c60 R08: dffffc0000000000 R09: fffffbfff1cabaae
R10: 0000000000000000 R11: dffffc0000000001 R12: 000000002009f080
R13: 0000000000001000 R14: ffffc900170d7d98 R15: 1ffff92002e1afb3
__clear_user arch/x86/include/asm/uaccess_64.h:174 [inline]
clear_user arch/x86/include/asm/uaccess_64.h:191 [inline]
iov_iter_zero+0x1cc/0xf90 lib/iov_iter.c:851
read_iter_zero+0x88/0x290 drivers/char/mem.c:497
call_read_iter include/linux/fs.h:1862 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x788/0xb00 fs/read_write.c:470
ksys_read+0x1a0/0x2c0 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f18be48c169
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:00007f18bf12b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f18be5abf80 RCX: 00007f18be48c169
RDX: 00000000ffffff1c RSI: 0000000020000080 RDI: 0000000000000008
RBP: 00007f18be4e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe3cfc9e9f R14: 00007f18bf12b300 R15: 0000000000022000
</TASK>
----------------
Code disassembly (best guess):
0: ff c7 inc %edi
2: 48 ff c9 dec %rcx
5: 75 f6 jne 0xfffffffd
7: c3 retq
8: 48 89 07 mov %rax,(%rdi)
b: 48 83 c7 08 add $0x8,%rdi
f: 83 e9 08 sub $0x8,%ecx
12: 74 f3 je 0x7
14: 83 f9 08 cmp $0x8,%ecx
17: 73 ef jae 0x8
19: eb e2 jmp 0xfffffffd
1b: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1)
22: 00 00 00
25: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
* 2a: 48 89 07 mov %rax,(%rdi) <-- trapping instruction
2d: 48 89 47 08 mov %rax,0x8(%rdi)
31: 48 89 47 10 mov %rax,0x10(%rdi)
35: 48 89 47 18 mov %rax,0x18(%rdi)
39: 48 89 47 20 mov %rax,0x20(%rdi)
3d: 48 rex.W
3e: 89 .byte 0x89
3f: 47 rex.RXB


---
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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: b19edac5992d Merge tag 'nolibc.2023.06.22a' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1425350b280000
kernel config: https://syzkaller.appspot.com/x/.config?x=33c8c2baba1cfc7e

dashboard link: https://syzkaller.appspot.com/bug?extid=e381e4c52ca8a53c3af7
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1515b4f0a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e1a4f239105a/disk-b19edac5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/25776c3e9785/vmlinux-b19edac5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ca7e959d451d/bzImage-b19edac5.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/531715d2031b/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e381e4...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 1 PID: 5874 at fs/udf/inode.c:2050 __udf_add_aext+0x550/0x6f0
Modules linked in:
CPU: 1 PID: 5874 Comm: syz-executor.0 Not tainted 6.4.0-syzkaller-01312-gb19edac5992d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023

RIP: 0010:__udf_add_aext+0x550/0x6f0 fs/udf/inode.c:2049

Code: 4c 89 e7 e8 02 1d e3 fe 49 8b 3c 24 4c 89 fe e8 56 21 03 ff 31 c0 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 e0 26 8b fe <0f> 0b e9 ed fb ff ff e8 d4 26 8b fe 0f 0b e9 5c fc ff ff e8 c8 26
RSP: 0018:ffffc900069a6af8 EFLAGS: 00010293
RAX: ffffffff83008300 RBX: 1ffff92000d34df9 RCX: ffff888028cb8000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff83007ee6 R09: ffffffff83007e16
R10: 0000000000000002 R11: ffff888028cb8000 R12: ffffc900069a6fc0
R13: 0000000000000004 R14: dffffc0000000000 R15: ffffc900069a6fc8
FS: 00007f9f9186d700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f9f9182c000 CR3: 000000001f981000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
udf_add_aext fs/udf/inode.c:2107 [inline]
udf_do_extend_file+0xcb5/0x11e0 fs/udf/inode.c:592
inode_getblk fs/udf/inode.c:822 [inline]
udf_map_block+0x16c0/0x4ff0 fs/udf/inode.c:450
__udf_get_block+0x126/0x410 fs/udf/inode.c:464

__block_write_begin_int+0x548/0x1a50 fs/buffer.c:2063
__block_write_begin fs/buffer.c:2113 [inline]
block_write_begin+0x9c/0x1f0 fs/buffer.c:2174
udf_write_begin+0x10d/0x1a0 fs/udf/inode.c:265
generic_perform_write+0x300/0x5e0 mm/filemap.c:3946
__generic_file_write_iter+0x17a/0x400 mm/filemap.c:4074
udf_file_write_iter+0x2fd/0x660 fs/udf/file.c:115
do_iter_write+0x84f/0xde0 fs/read_write.c:860
iter_file_splice_write+0x843/0xfe0 fs/splice.c:762
do_splice_from fs/splice.c:840 [inline]
direct_splice_actor+0xea/0x1c0 fs/splice.c:1027
splice_direct_to_actor+0x37e/0x9a0 fs/splice.c:982
do_splice_direct+0x286/0x3d0 fs/splice.c:1070
do_sendfile+0x623/0x1070 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1322 [inline]
__se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f9f90a8c389

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:00007f9f9186d168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f9f90babf80 RCX: 00007f9f90a8c389
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 00007f9f90ad7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0001000000201005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe5898ad1f R14: 00007f9f9186d300 R15: 0000000000022000
</TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 2aa91851ffa7cdfc0a63330d273115d38324b585
Author: Jiri Slaby (SUSE) <jiri...@kernel.org>
Date: Sun Aug 27 07:41:46 2023 +0000

tty: n_tty: extract ECHO_OP processing to a separate function

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=129425e5e80000
start commit: b19edac5992d Merge tag 'nolibc.2023.06.22a' of git://git.k..
git tree: upstream

kernel config: https://syzkaller.appspot.com/x/.config?x=33c8c2baba1cfc7e
dashboard link: https://syzkaller.appspot.com/bug?extid=e381e4c52ca8a53c3af7

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1515b4f0a80000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: tty: n_tty: extract ECHO_OP processing to a separate function

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Jan Kara]

Unlikely. The bisection seems to have gone wrong in the first step. I'd
rather suspect this was fixed by "fs: Block writes to mounted block
devices".

So:

#syz fix: fs: Block writes to mounted block devices

Honza

--
Jan Kara <ja...@suse.com>
SUSE Labs, CR