u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq c6c25c03258c59c5 written 48 min_key 0:36028797018963968:0 durability: 1 ptr: 0:27:0 gen 0  
  node offset 8/48 bset u64s 2088 bset byte offset 360: bad k->u64s 0 (min 3 max 253), fixing
==================================================================
BUG: KASAN: use-after-free in bkey_packed_valid+0x488/0x6c0 fs/bcachefs/btree_io.c:865
Read of size 1 at addr ffff8880453a0000 by task kworker/0:1H/37

CPU: 0 UID: 0 PID: 37 Comm: kworker/0:1H Not tainted 6.14.0-rc5-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: bcachefs_btree_read_complete btree_node_read_work
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
 bkey_packed_valid+0x488/0x6c0 fs/bcachefs/btree_io.c:865
 validate_bset_keys+0xeb5/0x1af0 fs/bcachefs/btree_io.c:987
 bch2_btree_node_read_done+0x2298/0x6180 fs/bcachefs/btree_io.c:1164
 btree_node_read_work+0x6dc/0x1380 fs/bcachefs/btree_io.c:1358
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x453a0
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 ffffea000114fb08 ffff88801fc44c20 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Reclaimable, gfp_mask 0x452cd0(GFP_KERNEL_ACCOUNT|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_RECLAIMABLE), pid 5318, tgid 5317 (syz-executor285), ts 79505389118, free_ts 79904883188
 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:4739
 __alloc_pages_noprof+0xa/0x30 mm/page_alloc.c:4773
 __alloc_pages_node_noprof include/linux/gfp.h:265 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:292 [inline]
 ___kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4239
 __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4266
 __do_kmalloc_node mm/slub.c:4282 [inline]
 __kmalloc_node_noprof+0x33a/0x4d0 mm/slub.c:4300
 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:662
 btree_node_data_alloc+0xdb/0x260 fs/bcachefs/btree_cache.c:156
 __bch2_btree_node_mem_alloc+0x201/0x420 fs/bcachefs/btree_cache.c:201
 bch2_fs_btree_cache_init+0x27a/0x630 fs/bcachefs/btree_cache.c:655
 bch2_fs_alloc fs/bcachefs/super.c:919 [inline]
 bch2_fs_open+0x2d2d/0x31e0 fs/bcachefs/super.c:2064
 bch2_fs_get_tree+0x738/0x17a0 fs/bcachefs/fs.c:2190
 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
page last free pid 5327 tgid 5327 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 __folio_put+0x2b3/0x360 mm/swap.c:112
 folio_put include/linux/mm.h:1489 [inline]
 free_large_kmalloc+0xfe/0x180 mm/slub.c:4728
 kfree+0x212/0x430 mm/slub.c:4751
 btree_bounce_free fs/bcachefs/btree_io.c:111 [inline]
 bch2_btree_node_read_done+0x3c89/0x6180 fs/bcachefs/btree_io.c:1243
 btree_node_read_work+0x6dc/0x1380 fs/bcachefs/btree_io.c:1358
 bch2_btree_node_read+0x2433/0x29f0
 bch2_btree_node_fill+0xca6/0x1370 fs/bcachefs/btree_cache.c:994
 bch2_btree_node_get_noiter+0x9d5/0xf70 fs/bcachefs/btree_cache.c:1261
 found_btree_node_is_readable fs/bcachefs/btree_node_scan.c:84 [inline]
 try_read_btree_node fs/bcachefs/btree_node_scan.c:213 [inline]
 read_btree_nodes_worker+0x1392/0x1fd0 fs/bcachefs/btree_node_scan.c:262
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff88804539ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804539ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880453a0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8880453a0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880453a0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================