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BUG: KASAN: use-after-free in check_dirent fs/bcachefs/fsck.c:2205 [inline]
BUG: KASAN: use-after-free in bch2_check_dirents+0x2acb/0x3ba0 fs/bcachefs/fsck.c:2230
Read of size 1 at addr ffff8880537e0140 by task syz.1.69/6332

CPU: 1 UID: 0 PID: 6332 Comm: syz.1.69 Not tainted 6.14.0-syzkaller-12886-ga1b5bd45d4ee #0 PREEMPT(full) 
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
 check_dirent fs/bcachefs/fsck.c:2205 [inline]
 bch2_check_dirents+0x2acb/0x3ba0 fs/bcachefs/fsck.c:2230
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:285
 bch2_fs_recovery+0x292a/0x3e20 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x2fb/0x610 fs/bcachefs/super.c:1060
 bch2_fs_get_tree+0x113e/0x18f0 fs/bcachefs/fs.c:2253
 vfs_get_tree+0x90/0x2b0 fs/super.c:1759
 do_new_mount+0x2cf/0xb70 fs/namespace.c:3878
 do_mount fs/namespace.c:4218 [inline]
 __do_sys_mount fs/namespace.c:4429 [inline]
 __se_sys_mount+0x38c/0x400 fs/namespace.c:4406
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4d3738e90a
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:00007f4d3829de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4d3829def0 RCX: 00007f4d3738e90a
RDX: 000020000000f640 RSI: 00002000000001c0 RDI: 00007f4d3829deb0
RBP: 000020000000f640 R08: 00007f4d3829def0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000001c0
R13: 00007f4d3829deb0 R14: 000000000000f61c R15: 0000200000000080
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x537e0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffffea00013fc808 ffff88813fffc688 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 6332, tgid 6331 (syz.1.69), ts 117066583422, free_ts 130391234567
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1717
 prep_new_page mm/page_alloc.c:1725 [inline]
 get_page_from_freelist+0x351d/0x36b0 mm/page_alloc.c:3652
 __alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4934
 __alloc_pages_noprof+0xa/0x30 mm/page_alloc.c:4968
 __alloc_pages_node_noprof include/linux/gfp.h:284 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:311 [inline]
 ___kmalloc_large_node+0x92/0x210 mm/slub.c:4275
 __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4303
 __do_kmalloc_node mm/slub.c:4319 [inline]
 __kvmalloc_node_noprof+0x7c/0x5a0 mm/slub.c:5016
 btree_bounce_alloc fs/bcachefs/btree_io.c:124 [inline]
 bch2_btree_node_read_done+0x393c/0x62c0 fs/bcachefs/btree_io.c:1224
 btree_node_read_work+0x6cb/0x1400 fs/bcachefs/btree_io.c:1366
 bch2_btree_node_read+0x2427/0x29e0 fs/bcachefs/btree_io.c:-1
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1796 [inline]
 bch2_btree_root_read+0x656/0x7e0 fs/bcachefs/btree_io.c:1818
 read_btree_roots+0x3d7/0xa80 fs/bcachefs/recovery.c:581
 bch2_fs_recovery+0x28e4/0x3e20 fs/bcachefs/recovery.c:928
 bch2_fs_start+0x2fb/0x610 fs/bcachefs/super.c:1060
 bch2_fs_get_tree+0x113e/0x18f0 fs/bcachefs/fs.c:2253
 vfs_get_tree+0x90/0x2b0 fs/super.c:1759
page last free pid 6332 tgid 6331 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_pages_ok+0xb17/0xd90 mm/page_alloc.c:1437
 __folio_put+0x2b5/0x360 mm/swap.c:112
 folio_put include/linux/mm.h:1563 [inline]
 free_large_kmalloc+0x143/0x1e0 mm/slub.c:4771
 kfree+0x216/0x430 mm/slub.c:4839
 btree_bounce_free fs/bcachefs/btree_io.c:112 [inline]
 btree_node_sort+0x1124/0x1870 fs/bcachefs/btree_io.c:380
 bch2_btree_post_write_cleanup+0x11a/0xaa0 fs/bcachefs/btree_io.c:2501
 bch2_btree_node_prep_for_write+0x35a/0x670 fs/bcachefs/btree_trans_commit.c:93
 bch2_trans_lock_write+0x66f/0xb60 fs/bcachefs/btree_trans_commit.c:129
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:840 [inline]
 __bch2_trans_commit+0x3252/0x9da0 fs/bcachefs/btree_trans_commit.c:1050
 bch2_trans_commit fs/bcachefs/btree_update.h:195 [inline]
 check_dirent fs/bcachefs/fsck.c:2200 [inline]
 bch2_check_dirents+0x2820/0x3ba0 fs/bcachefs/fsck.c:2230
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:285
 bch2_fs_recovery+0x292a/0x3e20 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x2fb/0x610 fs/bcachefs/super.c:1060
 bch2_fs_get_tree+0x113e/0x18f0 fs/bcachefs/fs.c:2253
 vfs_get_tree+0x90/0x2b0 fs/super.c:1759

Memory state around the buggy address:
 ffff8880537e0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880537e0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880537e0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff8880537e0180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880537e0200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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