Re: [syzbot] [xfs?] KASAN: slab-out-of-bounds Read in xlog_cksum

syzbot
2025-03-13T04:29:02Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-out-of-bounds Read in xlog_cksum

=======================================================
XFS (loop0): Mounting V5 Filesystem bfdc47fc-10d8-4eed-a562-11a831b3f791
==================================================================
BUG: KASAN: slab-out-of-bounds in crc32c_le_arch+0xc7/0x1b0 arch/x86/lib/crc32-glue.c:81
Read of size 8 at addr ffff888040eb5200 by task syz.0.16/5913

CPU: 0 UID: 0 PID: 5913 Comm: syz.0.16 Not tainted 6.14.0-rc6-syzkaller-gb7f94fcf5546 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0x16e/0x5b0 mm/kasan/report.c:521
kasan_report+0x143/0x180 mm/kasan/report.c:634
crc32c_le_arch+0xc7/0x1b0 arch/x86/lib/crc32-glue.c:81
__crc32c_le include/linux/crc32.h:36 [inline]
crc32c include/linux/crc32c.h:9 [inline]
xlog_cksum+0x91/0xf0 fs/xfs/xfs_log.c:1588
xlog_recover_process+0x78/0x1e0 fs/xfs/xfs_log_recover.c:2900
xlog_do_recovery_pass+0xa01/0xdc0 fs/xfs/xfs_log_recover.c:3235
xlog_verify_head+0x21f/0x5a0 fs/xfs/xfs_log_recover.c:1058
xlog_find_tail+0xa04/0xdf0 fs/xfs/xfs_log_recover.c:1315
xlog_recover+0xe1/0x540 fs/xfs/xfs_log_recover.c:3419
xfs_log_mount+0x252/0x3e0 fs/xfs/xfs_log.c:666
xfs_mountfs+0xfbb/0x2500 fs/xfs/xfs_mount.c:878
xfs_fs_fill_super+0x1223/0x1550 fs/xfs/xfs_super.c:1817
get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3560
do_mount fs/namespace.c:3900 [inline]
__do_sys_mount fs/namespace.c:4111 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f010618e90a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0106f3ce68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0106f3cef0 RCX: 00007f010618e90a
RDX: 0000400000000500 RSI: 0000400000000200 RDI: 00007f0106f3ceb0
RBP: 0000400000000500 R08: 00007f0106f3cef0 R09: 0000000002218a5d
R10: 0000000002218a5d R11: 0000000000000246 R12: 0000400000000200
R13: 00007f0106f3ceb0 R14: 0000000000009706 R15: 0000400000000100
</TASK>

Allocated by task 5913:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4294 [inline]
__kmalloc_node_noprof+0x290/0x4d0 mm/slub.c:4300
__kvmalloc_node_noprof+0x72/0x190 mm/util.c:662
xlog_do_recovery_pass+0x143/0xdc0 fs/xfs/xfs_log_recover.c:3016
xlog_verify_head+0x21f/0x5a0 fs/xfs/xfs_log_recover.c:1058
xlog_find_tail+0xa04/0xdf0 fs/xfs/xfs_log_recover.c:1315
xlog_recover+0xe1/0x540 fs/xfs/xfs_log_recover.c:3419
xfs_log_mount+0x252/0x3e0 fs/xfs/xfs_log.c:666
xfs_mountfs+0xfbb/0x2500 fs/xfs/xfs_mount.c:878
xfs_fs_fill_super+0x1223/0x1550 fs/xfs/xfs_super.c:1817
get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3560
do_mount fs/namespace.c:3900 [inline]
__do_sys_mount fs/namespace.c:4111 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888040eb5000
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes to the right of
allocated 512-byte region [ffff888040eb5000, ffff888040eb5200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40eb4
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801b041c80 ffffea0000d00580 dead000000000003
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff88801b041c80 ffffea0000d00580 dead000000000003
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 04fff00000000001 ffffea000103ad01 ffffffffffffffff 0000000000000000
head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2, tgid 2 (kthreadd), ts 23865404352, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
prep_new_page mm/page_alloc.c:1559 [inline]
get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
__alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4740
alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
alloc_slab_page mm/slub.c:2423 [inline]
allocate_slab+0x8f/0x3a0 mm/slub.c:2587
new_slab mm/slub.c:2640 [inline]
___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
__slab_alloc+0x58/0xa0 mm/slub.c:3916
__slab_alloc_node mm/slub.c:3991 [inline]
slab_alloc_node mm/slub.c:4152 [inline]
__kmalloc_cache_noprof+0x27b/0x390 mm/slub.c:4320
kmalloc_noprof include/linux/slab.h:901 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]
set_kthread_struct+0xc2/0x330 kernel/kthread.c:126
copy_process+0x1179/0x3cf0 kernel/fork.c:2331
kernel_clone+0x226/0x8e0 kernel/fork.c:2815
kernel_thread+0x1c0/0x250 kernel/fork.c:2877
create_kthread kernel/kthread.c:487 [inline]
kthreadd+0x60d/0x810 kernel/kthread.c:847
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
page_owner free stack trace missing

Memory state around the buggy address:
ffff888040eb5100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888040eb5180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888040eb5200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888040eb5280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888040eb5300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Tested on:

commit: b7f94fcf Merge tag 'sched_ext-for-6.14-rc6-fixes' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16f4cc78580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31c94a07ddad0b00
dashboard link: https://syzkaller.appspot.com/bug?extid=9f6d080dece587cfdd4c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.