running recovery pass check_backpointers_to_extents (16), currently at recovery_pass_empty (0)
  running recovery pass scan_for_btree_nodes (1), currently at recovery_pass_empty (0)
  ret btree_node_read_validate_error
bcachefs (loop0): error reading btree root btree=extents level=0: btree_node_read_error, fixing
==================================================================
BUG: KASAN: slab-out-of-bounds in bch2_btree_node_read_done+0xd3b/0x51f0 fs/bcachefs/btree_io.c:1138
Read of size 8 at addr ffff888071ff5e10 by task syz.0.16/6599

CPU: 0 UID: 0 PID: 6599 Comm: syz.0.16 Not tainted 6.16.0-rc3-syzkaller-g86731a2a651e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 bch2_btree_node_read_done+0xd3b/0x51f0 fs/bcachefs/btree_io.c:1138
 btree_node_read_work+0x426/0xe30 fs/bcachefs/btree_io.c:1411
 bch2_btree_node_read+0x887/0x2a00 fs/bcachefs/btree_io.c:-1
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1877 [inline]
 bch2_btree_root_read+0x5f0/0x760 fs/bcachefs/btree_io.c:1899
 read_btree_roots+0x2c2/0x880 fs/bcachefs/recovery.c:604
 bch2_fs_recovery+0x2574/0x3950 fs/bcachefs/recovery.c:979
 bch2_fs_start+0xa99/0xd90 fs/bcachefs/super.c:1203
 bch2_fs_get_tree+0xb02/0x14f0 fs/bcachefs/fs.c:2489
 vfs_get_tree+0x92/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3885
 do_mount fs/namespace.c:4222 [inline]
 __do_sys_mount fs/namespace.c:4433 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4410
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f18e398e90a
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:00007f18e4735e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f18e4735ef0 RCX: 00007f18e398e90a
RDX: 0000400000000100 RSI: 0000400000000080 RDI: 00007f18e4735eb0
RBP: 0000400000000100 R08: 00007f18e4735ef0 R09: 00000000022100c0
R10: 00000000022100c0 R11: 0000000000000246 R12: 0000400000000080
R13: 00007f18e4735eb0 R14: 0000000000005aa0 R15: 00004000000001c0
 </TASK>

Allocated by task 6599:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kvmalloc_node_noprof+0x30d/0x5f0 mm/slub.c:5015
 btree_node_data_alloc+0xdc/0x270 fs/bcachefs/btree_cache.c:150
 __bch2_btree_node_mem_alloc+0x1ef/0x420 fs/bcachefs/btree_cache.c:195
 bch2_fs_btree_cache_init+0x2de/0x690 fs/bcachefs/btree_cache.c:656
 bch2_fs_alloc fs/bcachefs/super.c:999 [inline]
 bch2_fs_open+0x1ceb/0x2570 fs/bcachefs/super.c:2423
 bch2_fs_get_tree+0x437/0x14f0 fs/bcachefs/fs.c:2473
 vfs_get_tree+0x92/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3885
 do_mount fs/namespace.c:4222 [inline]
 __do_sys_mount fs/namespace.c:4433 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4410
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888071ff5c00
 which belongs to the cache kmalloc-rcl-512 of size 512
The buggy address is located 16 bytes to the right of
 allocated 512-byte region [ffff888071ff5c00, ffff888071ff5e00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x71ff4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880715f2701
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a442dc0 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080100010 00000000f5000000 ffff8880715f2701
head: 00fff00000000040 ffff88801a442dc0 dead000000000122 0000000000000000
head: 0000000000000000 0000000080100010 00000000f5000000 ffff8880715f2701
head: 00fff00000000002 ffffea0001c7fd01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6599, tgid 6598 (syz.0.16), ts 134661824633, free_ts 134465944861
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kvmalloc_node_noprof+0x429/0x5f0 mm/slub.c:5015
 btree_node_data_alloc+0xdc/0x270 fs/bcachefs/btree_cache.c:150
 __bch2_btree_node_mem_alloc+0x1ef/0x420 fs/bcachefs/btree_cache.c:195
 bch2_fs_btree_cache_init+0x2de/0x690 fs/bcachefs/btree_cache.c:656
 bch2_fs_alloc fs/bcachefs/super.c:999 [inline]
 bch2_fs_open+0x1ceb/0x2570 fs/bcachefs/super.c:2423
 bch2_fs_get_tree+0x437/0x14f0 fs/bcachefs/fs.c:2473
 vfs_get_tree+0x92/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3885
 do_mount fs/namespace.c:4222 [inline]
 __do_sys_mount fs/namespace.c:4433 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4410
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
page last free pid 6603 tgid 6603 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc65/0xe60 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3186
 put_cpu_partial+0x17c/0x250 mm/slub.c:3261
 __slab_free+0x2f7/0x400 mm/slub.c:4513
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204
 vm_area_dup+0x2b/0x680 mm/vma_init.c:122
 __split_vma+0x1a9/0xa00 mm/vma.c:512
 vms_gather_munmap_vmas+0x4ab/0x12b0 mm/vma.c:1375
 __mmap_prepare mm/vma.c:2351 [inline]
 __mmap_region mm/vma.c:2607 [inline]
 mmap_region+0x678/0x1f30 mm/vma.c:2692
 do_mmap+0xc45/0x10d0 mm/mmap.c:561
 vm_mmap_pgoff+0x31b/0x4c0 mm/util.c:579
 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:607
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff888071ff5d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888071ff5d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888071ff5e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff888071ff5e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888071ff5f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================