[moderation] [bcachefs?] KASAN: slab-out-of-bounds Read in __bch2_checksum_bio

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a79be02bba5c Fix mis-uses of 'cc-option' for warning disab..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a28ecc580000
kernel config: https://syzkaller.appspot.com/x/.config?x=45c3bf6fd4cb6a10
dashboard link: https://syzkaller.appspot.com/bug?extid=c530d8b008015a573983
compiler: Debian clang version 15.0.6, Debian LLD 15.0.6
CC: [kent.ov...@linux.dev linux-b...@vger.kernel.org linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-a79be02b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/67b2dfe73a95/vmlinux-a79be02b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9ff8658186d9/bzImage-a79be02b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c530d8...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in __bch2_checksum_bio+0x2df/0x1070 fs/bcachefs/checksum.c:232
Read of size 8 at addr ffff888040e0dd40 by task kworker/u4:1/14

CPU: 0 UID: 0 PID: 14 Comm: kworker/u4:1 Not tainted 6.15.0-rc3-syzkaller-00032-ga79be02bba5c #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events_unbound __bch2_read_endio
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
__bch2_checksum_bio+0x2df/0x1070 fs/bcachefs/checksum.c:232
bch2_checksum_bio+0xbc/0x110 fs/bcachefs/checksum.c:252
__bch2_read_endio+0x606/0x1840 fs/bcachefs/io_read.c:750
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

Allocated by task 5340:
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+0x9d/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4341 [inline]
__kmalloc_noprof+0x28e/0x4d0 mm/slub.c:4353
kmalloc_noprof include/linux/slab.h:909 [inline]
kmalloc_array_noprof include/linux/slab.h:948 [inline]
bch2_data_update_bios_init+0x669/0xbe0 fs/bcachefs/data_update.c:672
bch2_data_update_init+0x5d18/0x7950 fs/bcachefs/data_update.c:897
bch2_move_extent+0x894/0x2680 fs/bcachefs/move.c:320
bch2_move_data_btree fs/bcachefs/move.c:666 [inline]
__bch2_move_data+0x2859/0x38e0 fs/bcachefs/move.c:713
do_rebalance_scan fs/bcachefs/rebalance.c:480 [inline]
do_rebalance fs/bcachefs/rebalance.c:546 [inline]
bch2_rebalance_thread+0xcef/0x1fa0 fs/bcachefs/rebalance.c:588
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888040e0dd00
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes to the right of
allocated 64-byte region [ffff888040e0dd00, ffff888040e0dd40)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40e0d
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff88801b0418c0 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5329, tgid 5328 (syz.0.0), ts 76639627066, free_ts 76373181480
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1718
prep_new_page mm/page_alloc.c:1726 [inline]
get_page_from_freelist+0x360a/0x37a0 mm/page_alloc.c:3688
__alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4970
alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301
alloc_slab_page mm/slub.c:2468 [inline]
allocate_slab+0x8f/0x3b0 mm/slub.c:2632
new_slab mm/slub.c:2686 [inline]
___slab_alloc+0xc3b/0x1500 mm/slub.c:3872
__slab_alloc+0x58/0xa0 mm/slub.c:3962
__slab_alloc_node mm/slub.c:4037 [inline]
slab_alloc_node mm/slub.c:4198 [inline]
__do_kmalloc_node mm/slub.c:4340 [inline]
__kmalloc_node_track_caller_noprof+0x2ef/0x4d0 mm/slub.c:4360
__do_krealloc mm/slub.c:4918 [inline]
krealloc_noprof+0x10f/0x300 mm/slub.c:4971
bch2_printbuf_make_room+0x1f1/0x350 fs/bcachefs/printbuf.c:59
prt_bytes fs/bcachefs/printbuf.h:219 [inline]
prt_str+0x3e/0x7d0 fs/bcachefs/printbuf.h:231
bch2_btree_id_level_to_text+0x24/0xa0 fs/bcachefs/btree_cache.c:1405
bch2_btree_path_to_text_short+0x200/0xfb0 fs/bcachefs/btree_iter.c:1507
__bch2_trans_paths_to_text+0xe5/0x180 fs/bcachefs/btree_iter.c:1575
bch2_trans_update_max_paths+0x173/0x420 fs/bcachefs/btree_iter.c:1611
btree_path_alloc+0x8d9/0xad0 fs/bcachefs/btree_iter.c:1708
page last free pid 40 tgid 40 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
__free_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2725
__slab_free+0x2c6/0x390 mm/slub.c:4567
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4161 [inline]
slab_alloc_node mm/slub.c:4210 [inline]
__do_kmalloc_node mm/slub.c:4340 [inline]
__kmalloc_noprof+0x238/0x4d0 mm/slub.c:4353
kmalloc_noprof include/linux/slab.h:909 [inline]
__bch2_trans_get+0x6ba/0xd40 fs/bcachefs/btree_iter.c:3373
btree_node_write_work+0x78e/0xcc0 fs/bcachefs/btree_io.c:2107
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
ffff888040e0dc00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888040e0dc80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff888040e0dd00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
^
ffff888040e0dd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888040e0de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.