syzbot

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BUG: KASAN: slab-use-after-free in close_fs_devices+0x81f/0x870 fs/btrfs/volumes.c:1182
Read of size 4 at addr ffff888030103930 by task syz.0.537/8850

CPU: 1 UID: 0 PID: 8850 Comm: syz.0.537 Not tainted 6.16.0-rc3-next-20250627-syzkaller #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
 close_fs_devices+0x81f/0x870 fs/btrfs/volumes.c:1182
 btrfs_close_devices+0xc5/0x560 fs/btrfs/volumes.c:1201
 btrfs_free_fs_info+0x4f/0x3c0 fs/btrfs/disk-io.c:1250
 deactivate_locked_super+0xb9/0x130 fs/super.c:474
 btrfs_get_tree_super fs/btrfs/super.c:-1 [inline]
 btrfs_get_tree_subvol fs/btrfs/super.c:2073 [inline]
 btrfs_get_tree+0xd1e/0x17f0 fs/btrfs/super.c:2107
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3902
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 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: 0033:0x7f9ff45900ca
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:00007f9ff5473e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9ff5473ef0 RCX: 00007f9ff45900ca
RDX: 0000200000000040 RSI: 0000200000000240 RDI: 00007f9ff5473eb0
RBP: 0000200000000040 R08: 00007f9ff5473ef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000240
R13: 00007f9ff5473eb0 R14: 00000000000050f3 R15: 00002000000002c0
 </TASK>

Allocated by task 8850:
 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]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4396
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 alloc_fs_devices+0x4f/0x1d0 fs/btrfs/volumes.c:384
 device_list_add+0x6b7/0x20b0 fs/btrfs/volumes.c:813
 btrfs_scan_one_device+0x3fd/0x5b0 fs/btrfs/volumes.c:1487
 btrfs_get_tree_super fs/btrfs/super.c:1856 [inline]
 btrfs_get_tree_subvol fs/btrfs/super.c:2073 [inline]
 btrfs_get_tree+0x433/0x17f0 fs/btrfs/super.c:2107
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3902
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 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

Freed by task 5847:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kfree+0x18e/0x440 mm/slub.c:4879
 btrfs_free_stale_devices+0x61c/0x6b0 fs/btrfs/volumes.c:564
 btrfs_scan_one_device+0x3d5/0x5b0 fs/btrfs/volumes.c:1481
 btrfs_control_ioctl+0x11f/0x360 fs/btrfs/super.c:2256
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 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 ffff888030103800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 304 bytes inside of
 freed 512-byte region [ffff888030103800, ffff888030103a00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x30100
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000c04001 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 Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5827, tgid 5827 (syz-executor), ts 69687502149, free_ts 16584297041
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1848
 prep_new_page mm/page_alloc.c:1856 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3855
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5145
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2487 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2655
 new_slab mm/slub.c:2709 [inline]
 ___slab_alloc+0xbeb/0x1410 mm/slub.c:3891
 __slab_alloc mm/slub.c:3981 [inline]
 __slab_alloc_node mm/slub.c:4056 [inline]
 slab_alloc_node mm/slub.c:4217 [inline]
 __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4391
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 inetdev_init+0x7d/0x500 net/ipv4/devinet.c:273
 inetdev_event+0x301/0x15b0 net/ipv4/devinet.c:1591
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 register_netdevice+0x1608/0x1ae0 net/core/dev.c:11184
 veth_newlink+0x5cc/0xa50 drivers/net/veth.c:1884
 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3823
 __rtnl_newlink net/core/rtnetlink.c:3940 [inline]
 rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2534
page last free pid 9 tgid 9 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1392 [inline]
 __free_frozen_pages+0xb80/0xd80 mm/page_alloc.c:2892
 vfree+0x25a/0x400 mm/vmalloc.c:3434
 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3353
 process_one_work kernel/workqueue.c:3239 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3322
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3403
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888030103800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030103880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888030103900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888030103980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030103a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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