loop4: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: slab-out-of-bounds in bch2_sb_downgrade_to_text+0x15ab/0x1f70 fs/bcachefs/sb-downgrade.c:185
Read of size 2 at addr ffff888052006000 by task syz-executor.4/7857

CPU: 0 PID: 7857 Comm: syz-executor.4 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+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 bch2_sb_downgrade_to_text+0x15ab/0x1f70 fs/bcachefs/sb-downgrade.c:185
 bch2_sb_field_validate+0x1f7/0x2d0 fs/bcachefs/super-io.c:1211
 bch2_sb_validate+0xa79/0xe10 fs/bcachefs/super-io.c:468
 __bch2_read_super+0xc9a/0x1460 fs/bcachefs/super-io.c:822
 bch2_fs_open+0x246/0xdf0 fs/bcachefs/super.c:2049
 bch2_mount+0x71d/0x1320 fs/bcachefs/fs.c:1903
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2a0 fs/super.c:1779
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f03b4e7f3aa
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:00007f03b5afcef8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f03b5afcf80 RCX: 00007f03b4e7f3aa
RDX: 0000000020011a00 RSI: 0000000020000000 RDI: 00007f03b5afcf40
RBP: 0000000020011a00 R08: 00007f03b5afcf80 R09: 0000000003a04000
R10: 0000000003a04000 R11: 0000000000000202 R12: 0000000020000000
R13: 00007f03b5afcf40 R14: 0000000000011a04 R15: 0000000020000600
 </TASK>

Allocated by task 7857:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 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+0x24e/0x4e0 mm/slub.c:3986
 __do_krealloc mm/slab_common.c:1192 [inline]
 krealloc+0x7d/0x120 mm/slab_common.c:1225
 bch2_sb_realloc+0x2fc/0x660 fs/bcachefs/super-io.c:189
 read_one_super+0x7d7/0x3a10 fs/bcachefs/super-io.c:659
 __bch2_read_super+0x65a/0x1460 fs/bcachefs/super-io.c:750
 bch2_fs_open+0x246/0xdf0 fs/bcachefs/super.c:2049
 bch2_mount+0x71d/0x1320 fs/bcachefs/fs.c:1903
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2a0 fs/super.c:1779
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888052004000
 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 [ffff888052004000, ffff888052006000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x52000
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 0000000000020002 00000001ffffffff 0000000000000000
head: 00fff00000000840 ffff888015042280 dead000000000122 0000000000000000
head: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
head: 00fff00000000003 ffffea0001480001 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7797, tgid 775461644 (syz-executor.3), ts 7797, free_ts 275653162403
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 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+0x5f/0x160 mm/slub.c:2175
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2391
 ___slab_alloc+0xc73/0x1260 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __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+0x2db/0x4e0 mm/slub.c:3973
 kmalloc_node include/linux/slab.h:648 [inline]
 kvmalloc_node+0x72/0x190 mm/util.c:634
 kvmalloc include/linux/slab.h:766 [inline]
 kvmalloc_array include/linux/slab.h:784 [inline]
 __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:471 [inline]
 ptr_ring_init include/linux/ptr_ring.h:489 [inline]
 wg_packet_queue_init+0x92/0x2f0 drivers/net/wireguard/queueing.c:32
 wg_newlink+0x2f2/0x640 drivers/net/wireguard/device.c:353
 rtnl_newlink_create net/core/rtnetlink.c:3494 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3714 [inline]
 rtnl_newlink+0x158f/0x20a0 net/core/rtnetlink.c:3727
 rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6595
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2559
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
page last free pid 2465 tgid 2465 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+0x97b/0xaa0 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 __folio_put_large+0x168/0x1d0 mm/swap.c:132
 __folio_put+0x299/0x390 mm/swap.c:140
 folio_put include/linux/mm.h:1508 [inline]
 free_large_kmalloc+0x105/0x1c0 mm/slub.c:4361
 kfree+0x1ca/0x3a0 mm/slub.c:4384
 wg_destruct+0x1f3/0x2e0 drivers/net/wireguard/device.c:258
 netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10593
 default_device_exit_batch+0xa14/0xa90 net/core/dev.c:11641
 ops_exit_list net/core/net_namespace.c:175 [inline]
 cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:637
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3348
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3429
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff888052005f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888052005f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888052006000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888052006080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888052006100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================