[syzbot] KASAN: slab-out-of-bounds Read in hex_dump_to_buffer

From: syzbot
Date: Sat Oct 01 2022 - 09:41:54 EST

Next message: kernel test robot: "[bvanassche:block-for-next 6/6] drivers/block/null_blk/main.c:1276:13: warning: variable 'len' is uninitialized when used here"
Previous message: syzbot: "[syzbot] WARNING: nested lock was not taken in evict"
Next in thread: syzbot: "Re: [syzbot] KASAN: slab-out-of-bounds Read in hex_dump_to_buffer"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hello,

syzbot found the following issue on:

HEAD commit: aaa11ce2ffc8 Add linux-next specific files for 20220923
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1773ecb8880000
kernel config: https://syzkaller.appspot.com/x/.config?x=186d1ff305f10294
dashboard link: https://syzkaller.appspot.com/bug?extid=489783e0c22fbb27d8e9
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/95c7bf83c07e/disk-aaa11ce2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b161cd56a7a3/vmlinux-aaa11ce2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+489783e0c22fbb27d8e9@xxxxxxxxxxxxxxxxxxxxxxxxx

ffff8880a5a1c930: 28 c9 a1 a5 80 88 ff ff 00 00 00 00 00 00 00 00 (...............
ffff8880a5a1c940: 40 c9 a1 a5 80 88 ff ff 40 c9 a1 a5 80 88 ff ff @.......@.......
ffff8880a5a1c950: 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
ffff8880a5a1c960: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
ffff8880a5a1c970: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
==================================================================
BUG: KASAN: slab-out-of-bounds in hex_dump_to_buffer+0xdc1/0xdf0 lib/hexdump.c:193
Read of size 1 at addr ffff8880a5a1c980 by task syz-executor.0/21885

CPU: 1 PID: 21885 Comm: syz-executor.0 Not tainted 6.0.0-rc6-next-20220923-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x15e/0x45d mm/kasan/report.c:395
kasan_report+0xbb/0x1f0 mm/kasan/report.c:495
hex_dump_to_buffer+0xdc1/0xdf0 lib/hexdump.c:193
print_hex_dump+0x12f/0x1d0 lib/hexdump.c:276
ea_get.cold+0xaa/0x197 fs/jfs/xattr.c:561
__jfs_setxattr+0xdb/0xfc0 fs/jfs/xattr.c:671
__jfs_xattr_set+0xc9/0x150 fs/jfs/xattr.c:917
__vfs_setxattr+0x115/0x180 fs/xattr.c:182
__vfs_setxattr_noperm+0x125/0x5f0 fs/xattr.c:216
__vfs_setxattr_locked+0x1cf/0x260 fs/xattr.c:277
vfs_setxattr+0x13f/0x330 fs/xattr.c:309
setxattr+0x146/0x160 fs/xattr.c:617
path_setxattr+0x197/0x1c0 fs/xattr.c:636
__do_sys_lsetxattr fs/xattr.c:659 [inline]
__se_sys_lsetxattr fs/xattr.c:655 [inline]
__x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:655
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f56a6e8a5a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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:00007f56a800f168 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f56a6fabf80 RCX: 00007f56a6e8a5a9
RDX: 0000000020005280 RSI: 0000000020000180 RDI: 0000000020000140
RBP: 00007f56a6ee5580 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000016 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe8902fcff R14: 00007f56a800f300 R15: 0000000000022000
</TASK>

Allocated by task 21885:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
kasan_set_track+0x21/0x30 mm/kasan/common.c:52
__kasan_slab_alloc+0x7e/0x80 mm/kasan/common.c:325
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slab.h:754 [inline]
slab_alloc_node mm/slub.c:3336 [inline]
slab_alloc mm/slub.c:3344 [inline]
__kmem_cache_alloc_lru mm/slub.c:3351 [inline]
kmem_cache_alloc_lru+0x255/0x730 mm/slub.c:3367
alloc_inode_sb include/linux/fs.h:3106 [inline]
jfs_alloc_inode+0x23/0x60 fs/jfs/super.c:105
alloc_inode+0x61/0x230 fs/inode.c:259
iget_locked+0x1b7/0x6f0 fs/inode.c:1286
jfs_iget+0x1a/0x4d0 fs/jfs/inode.c:29
jfs_lookup+0x246/0x2f0 fs/jfs/namei.c:1462
__lookup_slow+0x24c/0x460 fs/namei.c:1685
lookup_slow fs/namei.c:1702 [inline]
walk_component+0x33f/0x5a0 fs/namei.c:1993
lookup_last fs/namei.c:2450 [inline]
path_lookupat+0x1ba/0x840 fs/namei.c:2474
filename_lookup+0x1ce/0x590 fs/namei.c:2503
user_path_at_empty+0x42/0x60 fs/namei.c:2876
user_path_at include/linux/namei.h:57 [inline]
do_mount fs/namespace.c:3380 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x1ea/0x300 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
__kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
call_rcu+0x99/0x820 kernel/rcu/tree.c:2796
destroy_inode+0x129/0x1b0 fs/inode.c:314
iput_final fs/inode.c:1747 [inline]
iput.part.0+0x59b/0x880 fs/inode.c:1773
iput+0x58/0x70 fs/inode.c:1763
diFreeSpecial+0x73/0x100 fs/jfs/jfs_imap.c:548
jfs_umount+0x130/0x3f0 fs/jfs/jfs_umount.c:65
jfs_put_super+0x81/0x190 fs/jfs/super.c:194
generic_shutdown_super+0x154/0x410 fs/super.c:491
kill_block_super+0x97/0xf0 fs/super.c:1427
deactivate_locked_super+0x94/0x160 fs/super.c:331
deactivate_super+0xad/0xd0 fs/super.c:362
cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1186
task_work_run+0x16b/0x270 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:296
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
__kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
call_rcu+0x99/0x820 kernel/rcu/tree.c:2796
destroy_inode+0x129/0x1b0 fs/inode.c:314
iput_final fs/inode.c:1747 [inline]
iput.part.0+0x59b/0x880 fs/inode.c:1773
iput+0x58/0x70 fs/inode.c:1763
jfs_put_super+0x152/0x190 fs/jfs/super.c:201
generic_shutdown_super+0x154/0x410 fs/super.c:491
kill_block_super+0x97/0xf0 fs/super.c:1427
deactivate_locked_super+0x94/0x160 fs/super.c:331
deactivate_super+0xad/0xd0 fs/super.c:362
cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1186
task_work_run+0x16b/0x270 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:296
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff8880a5a1c0c0
which belongs to the cache jfs_ip of size 2240
The buggy address is located 0 bytes to the right of
2240-byte region [ffff8880a5a1c0c0, ffff8880a5a1c980)

The buggy address belongs to the physical page:
page:ffffea0002968600 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffffea0002771e00 pfn:0xa5a18
head:ffffea0002968600 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff888027fc6101
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff88801ba46b40 dead0000800d000d 0000000000000000
raw: ffffea0002771e00 dead000000000003 00000001ffffffff ffff888027fc6101
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 15578, tgid 15577 (syz-executor.1), ts 741966923770, free_ts 738328900782
prep_new_page mm/page_alloc.c:2538 [inline]
get_page_from_freelist+0x1092/0x2d20 mm/page_alloc.c:4287
__alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5546
alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280
alloc_slab_page mm/slub.c:1739 [inline]
allocate_slab+0x213/0x300 mm/slub.c:1884
new_slab mm/slub.c:1937 [inline]
___slab_alloc+0xac1/0x1430 mm/slub.c:3119
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3217
slab_alloc_node mm/slub.c:3302 [inline]
slab_alloc mm/slub.c:3344 [inline]
__kmem_cache_alloc_lru mm/slub.c:3351 [inline]
kmem_cache_alloc_lru+0x4aa/0x730 mm/slub.c:3367
alloc_inode_sb include/linux/fs.h:3106 [inline]
jfs_alloc_inode+0x23/0x60 fs/jfs/super.c:105
alloc_inode+0x61/0x230 fs/inode.c:259
new_inode_pseudo fs/inode.c:1018 [inline]
new_inode+0x27/0x270 fs/inode.c:1046
diReadSpecial+0x4f/0x6d0 fs/jfs/jfs_imap.c:422
jfs_mount+0x1da/0x7b0 fs/jfs/jfs_mount.c:108
jfs_fill_super+0x5a4/0xc70 fs/jfs/super.c:556
mount_bdev+0x34d/0x410 fs/super.c:1400
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1530
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1458 [inline]
free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1508
free_unref_page_prepare mm/page_alloc.c:3386 [inline]
free_unref_page+0x19/0x4d0 mm/page_alloc.c:3482
__unfreeze_partials+0x17c/0x1a0 mm/slub.c:2532
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x62/0x80 mm/kasan/common.c:302
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slab.h:754 [inline]
slab_alloc_node mm/slub.c:3336 [inline]
slab_alloc mm/slub.c:3344 [inline]
__kmem_cache_alloc_lru mm/slub.c:3351 [inline]
kmem_cache_alloc+0x2b7/0x3d0 mm/slub.c:3360
getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
getname_flags include/linux/audit.h:320 [inline]
getname+0x8e/0xd0 fs/namei.c:218
do_sys_openat2+0xf5/0x4c0 fs/open.c:1304
do_sys_open fs/open.c:1326 [inline]
__do_sys_openat fs/open.c:1342 [inline]
__se_sys_openat fs/open.c:1337 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1337
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff8880a5a1c880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880a5a1c900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a5a1c980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8880a5a1ca00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a5a1ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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 syzkaller@xxxxxxxxxxxxxxxx.

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

Next message: kernel test robot: "[bvanassche:block-for-next 6/6] drivers/block/null_blk/main.c:1276:13: warning: variable 'len' is uninitialized when used here"
Previous message: syzbot: "[syzbot] WARNING: nested lock was not taken in evict"
Next in thread: syzbot: "Re: [syzbot] KASAN: slab-out-of-bounds Read in hex_dump_to_buffer"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]