[syzbot] [jfs?] KASAN: slab-out-of-bounds Read in jfs_readdir

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e8f60cd7db24 Merge tag 'perf-tools-fixes-for-v6.2-2-2023-0..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13af86a1480000
kernel config: https://syzkaller.appspot.com/x/.config?x=2b6ecad960fc703e
dashboard link: https://syzkaller.appspot.com/bug?extid=f328fbf8718edb712341
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13ab6a36480000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11647bbe480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/783306915ec2/disk-e8f60cd7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2ff1bb24fb5d/vmlinux-e8f60cd7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/08e9c5fa68d4/bzImage-e8f60cd7.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/90a9788dcb4a/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f328fb...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: slab-out-of-bounds in jfs_readdir+0x375e/0x4230 fs/jfs/jfs_dtree.c:2889
Read of size 1 at addr ffff888075357f75 by task syz-executor300/5071

CPU: 1 PID: 5071 Comm: syz-executor300 Not tainted 6.2.0-rc3-syzkaller-00030-ge8f60cd7db24 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:306 [inline]
print_report+0x15e/0x45d mm/kasan/report.c:417
kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
jfs_readdir+0x375e/0x4230 fs/jfs/jfs_dtree.c:2889
iterate_dir+0x1fd/0x6f0 fs/readdir.c:67
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64 fs/readdir.c:354 [inline]
__x64_sys_getdents64+0x13e/0x2c0 fs/readdir.c:354
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: 0033:0x7fbeecd7b9a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed1b8d6f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 000000000000cdbe RCX: 00007fbeecd7b9a9
RDX: 00000000000000c5 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007ffed1b8d720 R09: 00007ffed1b8d720
R10: 0000000000005d45 R11: 0000000000000246 R12: 00007ffed1b8d71c
R13: 00007ffed1b8d750 R14: 00007ffed1b8d730 R15: 0000000000000004
</TASK>

The buggy address belongs to the object at ffff888075356e58
which belongs to the cache ext4_inode_cache of size 2440
The buggy address is located 1941 bytes to the right of
2440-byte region [ffff888075356e58, ffff8880753577e0)

The buggy address belongs to the physical page:
page:ffffea0001d4d400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75350
head:ffffea0001d4d400 order:3 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff888018d9c140 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_RECLAIMABLE), pid 5069, tgid 5069 (syz-executor300), ts 52178760853, free_ts 12054506429
prep_new_page mm/page_alloc.c:2531 [inline]
get_page_from_freelist+0x119c/0x2ce0 mm/page_alloc.c:4283
__alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5549
alloc_pages+0x1aa/0x270 mm/mempolicy.c:2286
alloc_slab_page mm/slub.c:1851 [inline]
allocate_slab+0x25f/0x350 mm/slub.c:1998
new_slab mm/slub.c:2051 [inline]
___slab_alloc+0xa91/0x1400 mm/slub.c:3193
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292
__slab_alloc_node mm/slub.c:3345 [inline]
slab_alloc_node mm/slub.c:3442 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc_lru+0x4dc/0x760 mm/slub.c:3483
alloc_inode_sb include/linux/fs.h:3119 [inline]
ext4_alloc_inode+0x28/0x680 fs/ext4/super.c:1321
alloc_inode+0x61/0x230 fs/inode.c:259
new_inode_pseudo fs/inode.c:1018 [inline]
new_inode+0x2b/0x280 fs/inode.c:1046
__ext4_new_inode+0x399/0x57d0 fs/ext4/ialloc.c:959
ext4_symlink+0x5ac/0xa00 fs/ext4/namei.c:3373
vfs_symlink fs/namei.c:4401 [inline]
vfs_symlink+0x369/0x5c0 fs/namei.c:4386
do_symlinkat+0x250/0x2c0 fs/namei.c:4430
__do_sys_symlink fs/namei.c:4452 [inline]
__se_sys_symlink fs/namei.c:4450 [inline]
__x64_sys_symlink+0x79/0x90 fs/namei.c:4450
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1446 [inline]
free_pcp_prepare+0x65c/0xc00 mm/page_alloc.c:1496
free_unref_page_prepare mm/page_alloc.c:3369 [inline]
free_unref_page+0x1d/0x490 mm/page_alloc.c:3464
free_contig_range+0xb5/0x180 mm/page_alloc.c:9485
destroy_args+0xa8/0x64c mm/debug_vm_pgtable.c:998
debug_vm_pgtable+0x28de/0x296f mm/debug_vm_pgtable.c:1318
do_one_initcall+0x141/0x790 init/main.c:1306
do_initcall_level init/main.c:1379 [inline]
do_initcalls init/main.c:1395 [inline]
do_basic_setup init/main.c:1414 [inline]
kernel_init_freeable+0x6f9/0x782 init/main.c:1634
kernel_init+0x1e/0x1d0 init/main.c:1522
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Memory state around the buggy address:
ffff888075357e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888075357e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888075357f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888075357f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888075358000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
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[syzbot]

syzbot suspects this issue was fixed by commit:

commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <ja...@suse.cz>
Date: Wed Nov 1 17:43:10 2023 +0000

fs: Block writes to mounted block devices

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16b9e3ca180000
start commit: 2772d7df3c93 Merge tag 'riscv-for-linus-6.5-rc2' of git://..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=6d0f369ef5fb88c9
dashboard link: https://syzkaller.appspot.com/bug?extid=f328fbf8718edb712341
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10233f38a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d35c1aa80000

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

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

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

[Jan Kara]

On Sun 03-03-24 19:53:03, syzbot wrote:
> syzbot suspects this issue was fixed by commit:
>
> commit 6f861765464f43a71462d52026fbddfc858239a5
> Author: Jan Kara <ja...@suse.cz>
> Date: Wed Nov 1 17:43:10 2023 +0000
>
> fs: Block writes to mounted block devices
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16b9e3ca180000
> start commit: 2772d7df3c93 Merge tag 'riscv-for-linus-6.5-rc2' of git://..
> git tree: upstream
> kernel config: https://syzkaller.appspot.com/x/.config?x=6d0f369ef5fb88c9
> dashboard link: https://syzkaller.appspot.com/bug?extid=f328fbf8718edb712341
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10233f38a80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d35c1aa80000
>
> If the result looks correct, please mark the issue as fixed by replying with:

Likely corrupted fs so that logdev == fsdev and this fixed it. We could
perhaps add some sanity checking but does anybody care enough about JFS?

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

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