u64s 8 type dirent 4096:8130059955150870709:U32_MAX len 0 ver 0: lost+found -> 4097 type dir, fixing
dirent points to missing inode:
u64s 8 type dirent 4096:8130059955150870709:U32_MAX len 0 ver 0: lost+found -> 4097 type dir, fixing
==================================================================
BUG: KASAN: use-after-free in check_dirent+0x2455/0x2620 fs/bcachefs/fsck.c:2443
Read of size 1 at addr ffff888048e80160 by task syz.2.1455/9776

CPU: 1 UID: 0 PID: 9776 Comm: syz.2.1455 Not tainted 6.14.0-rc4-syzkaller #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+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xd9/0x110 mm/kasan/report.c:634
 check_dirent+0x2455/0x2620 fs/bcachefs/fsck.c:2443
 bch2_check_dirents+0x409/0x780 fs/bcachefs/fsck.c:2468
 bch2_run_recovery_pass+0x91/0x1a0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x3f4/0x8f0 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x2973/0x43d0 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x343/0x660 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0x1118/0x1760 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x8e/0x340 fs/super.c:1814
 do_new_mount fs/namespace.c:3560 [inline]
 path_mount+0x14e6/0x1f10 fs/namespace.c:3887
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount fs/namespace.c:4088 [inline]
 __x64_sys_mount+0x28f/0x310 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1dbdd8e90a
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:00007f1dbec45e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1dbec45ef0 RCX: 00007f1dbdd8e90a
RDX: 0000400000000200 RSI: 0000400000005900 RDI: 00007f1dbec45eb0
RBP: 0000400000000200 R08: 00007f1dbec45ef0 R09: 0000000001000081
R10: 0000000001000081 R11: 0000000000000246 R12: 0000400000005900
R13: 00007f1dbec45eb0 R14: 00000000000059e9 R15: 0000400000000080
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888048e86000 pfn:0x48e80
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffffea0001471808 ffff88813fffc008 0000000000000000
raw: ffff888048e86000 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 9776, tgid 9775 (syz.2.1455), ts 369044179402, free_ts 376062097419
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x221/0x2470 mm/page_alloc.c:4739
 __alloc_pages_noprof+0xb/0x1b0 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+0x84/0x1b0 mm/slub.c:4239
 __kmalloc_large_node_noprof+0x1c/0x70 mm/slub.c:4266
 __do_kmalloc_node mm/slub.c:4282 [inline]
 __kmalloc_node_noprof.cold+0x5/0x5f mm/slub.c:4300
 __kvmalloc_node_noprof+0x6f/0x1a0 mm/util.c:662
 btree_bounce_alloc+0x11e/0x210 fs/bcachefs/btree_io.c:123
 bch2_btree_node_read_done+0xee6/0x4dc0 fs/bcachefs/btree_io.c:1222
 btree_node_read_work+0x569/0x1060 fs/bcachefs/btree_io.c:1358
 bch2_btree_node_read+0x8aa/0xe70 fs/bcachefs/btree_io.c:1748
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1789 [inline]
 bch2_btree_root_read+0x2d2/0x470 fs/bcachefs/btree_io.c:1811
 read_btree_roots fs/bcachefs/recovery.c:581 [inline]
 bch2_fs_recovery+0x2039/0x43d0 fs/bcachefs/recovery.c:928
 bch2_fs_start+0x343/0x660 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0x1118/0x1760 fs/bcachefs/fs.c:2203
page last free pid 9776 tgid 9775 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 __free_pages_ok+0x62b/0xe50 mm/page_alloc.c:1271
 __folio_put+0x32a/0x450 mm/swap.c:112
 kvfree+0x47/0x50 mm/util.c:705
 btree_bounce_free fs/bcachefs/btree_io.c:111 [inline]
 btree_node_sort+0xf9f/0x14f0 fs/bcachefs/btree_io.c:379
 bch2_btree_post_write_cleanup fs/bcachefs/btree_io.c:2293 [inline]
 bch2_btree_post_write_cleanup+0x145/0x600 fs/bcachefs/btree_io.c:2267
 bch2_btree_node_prep_for_write+0x35b/0x550 fs/bcachefs/btree_trans_commit.c:93
 bch2_trans_lock_write+0x6c5/0x8e0 fs/bcachefs/btree_trans_commit.c:129
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:862 [inline]
 __bch2_trans_commit+0x2264/0x7d70 fs/bcachefs/btree_trans_commit.c:1070
 bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
 check_dirent+0xff1/0x2620 fs/bcachefs/fsck.c:2438
 bch2_check_dirents+0x409/0x780 fs/bcachefs/fsck.c:2468
 bch2_run_recovery_pass+0x91/0x1a0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x3f4/0x8f0 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x2973/0x43d0 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x343/0x660 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0x1118/0x1760 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x8e/0x340 fs/super.c:1814

Memory state around the buggy address:
 ffff888048e80000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888048e80080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888048e80100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff888048e80180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888048e80200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
directory 4096:4294967295 with wrong i_size: got 0, should be 352, fixing
key in missing inode:
  u64s 7 type dirent 4098:5675548428000973578:U32_MAX len 0 ver 0: file1 -> 4100 type lnk, fixing
key in missing inode:
  u64s 7 type dirent 4098:8977922886548783724:U32_MAX len 0 ver 0: file0 -> 4099 type reg, fixing
 done
bcachefs (loop2): resume_logged_ops... done
bcachefs (loop2): delete_dead_inodes... done
bcachefs (loop2): Fixed errors, running fsck a second time to verify fs is clean
bcachefs (loop2): check_lrus... done
bcachefs (loop2): check_backpointers_to_extents... done
bcachefs (loop2): check_extents_to_backpointers... done
bcachefs (loop2): check_inodes... done
bcachefs (loop2): check_dirents...
directory 4096:4294967295 with wrong i_nlink: got 2, should be 0, fixing
directory 4096:4294967295 with wrong i_size: got 352, should be 232, fixing
key in missing inode:
  u64s 7 type dirent 4098:5675548428000973578:U32_MAX len 0 ver 0: file1 -> 4100 type lnk, fixing
key in missing inode:
  u64s 7 type dirent 4098:8977922886548783724:U32_MAX len 0 ver 0: file0 -> 4099 type reg, fixing
 done
bcachefs (loop2): resume_logged_ops... done
bcachefs (loop2): delete_dead_inodes... done
bcachefs (loop2): Second fsck run was not clean
bcachefs (loop2): going read-only
bcachefs (loop2): finished waiting for writes to stop
bcachefs (loop2): flushing journal and stopping allocators, journal seq 26
bcachefs (loop2): flushing journal and stopping allocators complete, journal seq 26
bcachefs (loop2): clean shutdown complete, journal seq 27
bcachefs (loop2): marking filesystem clean
bcachefs (loop2): done starting filesystem
bcachefs (loop2): missing subvolume 1
bcachefs (loop2): bch2_fs_get_tree(): error mounting: error getting root inode ENOENT_bkey_type_mismatch
bcachefs (loop2): shutting down
bcachefs (loop2): shutdown complete
bcachefs: bch2_fs_get_tree() error: ENOENT_bkey_type_mismatch
syz.2.1455 (9776) used greatest stack depth: 15792 bytes left