loop2: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: slab-out-of-bounds in bch2_sb_downgrade_to_text+0x58d/0x680 fs/bcachefs/sb-downgrade.c:185
Read of size 2 at addr ffff88807eff2000 by task syz-executor.2/10161

CPU: 1 PID: 10161 Comm: syz-executor.2 Not tainted 6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bch2_sb_downgrade_to_text+0x58d/0x680 fs/bcachefs/sb-downgrade.c:185
 __bch2_sb_field_to_text+0x123/0x1e0 fs/bcachefs/super-io.c:1228
 bch2_sb_field_validate+0x248/0x2d0 fs/bcachefs/super-io.c:1211
 bch2_sb_validate.isra.0+0x6d8/0xce0 fs/bcachefs/super-io.c:468
 __bch2_read_super+0x93c/0x12a0 fs/bcachefs/super-io.c:822
 bch2_fs_open+0x3e5/0x1110 fs/bcachefs/super.c:2049
 bch2_mount+0xdcc/0x1130 fs/bcachefs/fs.c:1903
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1779
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __x64_sys_mount+0x297/0x320 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc4f867f3aa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc4f9378ef8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fc4f9378f80 RCX: 00007fc4f867f3aa
RDX: 0000000020011a00 RSI: 0000000020000000 RDI: 00007fc4f9378f40
RBP: 0000000020011a00 R08: 00007fc4f9378f80 R09: 0000000003a04000
R10: 0000000003a04000 R11: 0000000000000202 R12: 0000000020000000
R13: 00007fc4f9378f40 R14: 0000000000011a04 R15: 0000000020000600
 </TASK>

Allocated by task 10161:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:3966 [inline]
 __kmalloc_node_track_caller+0x220/0x470 mm/slub.c:3986
 __do_krealloc mm/slab_common.c:1192 [inline]
 krealloc+0x5d/0x100 mm/slab_common.c:1225
 bch2_sb_realloc+0x242/0x5d0 fs/bcachefs/super-io.c:189
 read_one_super+0x318/0x12a0 fs/bcachefs/super-io.c:659
 __bch2_read_super+0x4d6/0x12a0 fs/bcachefs/super-io.c:750
 bch2_fs_open+0x3e5/0x1110 fs/bcachefs/super.c:2049
 bch2_mount+0xdcc/0x1130 fs/bcachefs/fs.c:1903
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1779
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __x64_sys_mount+0x297/0x320 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807eff0000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 0 bytes to the right of
 allocated 8192-byte region [ffff88807eff0000, ffff88807eff2000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7eff0
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888015042280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
head: 00fff00000000840 ffff888015042280 dead000000000122 0000000000000000
head: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
head: 00fff00000000003 ffffea0001fbfc01 dead000000000122 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 10160, tgid -1859258684 (syz-executor.2), ts 10161, free_ts 539254285946
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0xcc/0x3a0 mm/slub.c:2391
 ___slab_alloc+0x66d/0x1790 mm/slub.c:3525
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 __do_kmalloc_node mm/slub.c:3965 [inline]
 __kmalloc_node_track_caller+0x367/0x470 mm/slub.c:3986
 __do_krealloc mm/slab_common.c:1192 [inline]
 krealloc+0x5d/0x100 mm/slab_common.c:1225
 bch2_sb_realloc+0x242/0x5d0 fs/bcachefs/super-io.c:189
 read_one_super+0x318/0x12a0 fs/bcachefs/super-io.c:659
 __bch2_read_super+0x4d6/0x12a0 fs/bcachefs/super-io.c:750
 bch2_fs_open+0x3e5/0x1110 fs/bcachefs/super.c:2049
 bch2_mount+0xdcc/0x1130 fs/bcachefs/fs.c:1903
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1779
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3679
page last free pid 10184 tgid 10184 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347
 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487
 __put_partials+0x14c/0x170 mm/slub.c:2906
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc_lru+0x142/0x6f0 mm/slub.c:3864
 alloc_inode_sb include/linux/fs.h:3091 [inline]
 proc_alloc_inode+0x25/0x200 fs/proc/inode.c:57
 alloc_inode+0x5d/0x230 fs/inode.c:261
 new_inode_pseudo fs/inode.c:1007 [inline]
 new_inode+0x22/0x270 fs/inode.c:1033
 proc_pid_make_inode+0x22/0x160 fs/proc/base.c:1892
 proc_pident_instantiate+0x85/0x320 fs/proc/base.c:2638
 proc_pident_lookup+0x1e7/0x2c0 fs/proc/base.c:2674
 lookup_open.isra.0+0x928/0x13c0 fs/namei.c:3475
 open_last_lookups fs/namei.c:3566 [inline]
 path_openat+0x92f/0x2990 fs/namei.c:3796
 do_filp_open+0x1dc/0x430 fs/namei.c:3826

Memory state around the buggy address:
 ffff88807eff1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807eff1f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807eff2000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff88807eff2080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807eff2100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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