u64s 7 type extent 536870913:24:U32_MAX len 24 ver 0: durability: 1 crc: c_size 8 size 24 offset 0 nonce 0 csum none 0:0  compress lz4 ptr: 0:34:8 gen 0, fixing
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BUG: KASAN: use-after-free in __extent_entry_type fs/bcachefs/extents.h:53 [inline]
BUG: KASAN: use-after-free in extent_entry_is_crc fs/bcachefs/extents.h:120 [inline]
BUG: KASAN: use-after-free in check_extent_overbig+0x27b/0x7d0 fs/bcachefs/fsck.c:1773
Read of size 8 at addr ffff88805cb00100 by task syz.1.16/6717

CPU: 0 UID: 0 PID: 6717 Comm: syz.1.16 Not tainted 6.14.0-rc5-syzkaller-00214-g21e4543a2e2f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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
 __extent_entry_type fs/bcachefs/extents.h:53 [inline]
 extent_entry_is_crc fs/bcachefs/extents.h:120 [inline]
 check_extent_overbig+0x27b/0x7d0 fs/bcachefs/fsck.c:1773
 bch2_check_extents+0x9f1/0x6170 fs/bcachefs/fsck.c:1906
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x265a/0x3de0 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 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: 0033:0x7fdfbf3816ba
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:00007fdfbe5fde88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fdfbe5fdf10 RCX: 00007fdfbf3816ba
RDX: 00000000200000c0 RSI: 0000000020000000 RDI: 00007fdfbe5fded0
RBP: 00000000200000c0 R08: 00007fdfbe5fdf10 R09: 0000000000800000
R10: 0000000000800000 R11: 0000000000000246 R12: 0000000020000000
R13: 00007fdfbe5fded0 R14: 0000000000005991 R15: 0000000020006a00
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5cb00
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffffea00019bb008 ffff88813fffc788 0000000000000000
raw: 0000000000000000 0000000000000005 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 5, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 6717, tgid 6716 (syz.1.16), ts 117129463677, free_ts 117249186679
 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+0x3651/0x37a0 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_bounce_alloc fs/bcachefs/btree_io.c:123 [inline]
 btree_node_sort+0x620/0x1830 fs/bcachefs/btree_io.c:322
 bch2_btree_post_write_cleanup+0x11a/0xa70 fs/bcachefs/btree_io.c:2293
 bch2_btree_node_prep_for_write+0x345/0x660 fs/bcachefs/btree_trans_commit.c:93
 bch2_trans_lock_write+0x68e/0xc60 fs/bcachefs/btree_trans_commit.c:129
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:862 [inline]
 __bch2_trans_commit+0x258c/0x9790 fs/bcachefs/btree_trans_commit.c:1070
 bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
 check_extent fs/bcachefs/fsck.c:1863 [inline]
 bch2_check_extents+0x41a7/0x6170 fs/bcachefs/fsck.c:1906
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
page last free pid 6717 tgid 6716 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 __free_pages_ok+0xbbc/0xe40 mm/page_alloc.c:1271
 __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]
 btree_node_sort+0x1100/0x1830 fs/bcachefs/btree_io.c:379
 bch2_btree_post_write_cleanup+0x11a/0xa70 fs/bcachefs/btree_io.c:2293
 bch2_btree_node_prep_for_write+0x345/0x660 fs/bcachefs/btree_trans_commit.c:93
 bch2_trans_lock_write+0x68e/0xc60 fs/bcachefs/btree_trans_commit.c:129
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:862 [inline]
 __bch2_trans_commit+0x258c/0x9790 fs/bcachefs/btree_trans_commit.c:1070
 bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
 check_extent fs/bcachefs/fsck.c:1863 [inline]
 bch2_check_extents+0x41a7/0x6170 fs/bcachefs/fsck.c:1906
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x265a/0x3de0 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814

Memory state around the buggy address:
 ffff88805cb00000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805cb00080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805cb00100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88805cb00180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805cb00200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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