================================================================== BUG: KASAN: slab-use-after-free in close_fs_devices+0x81f/0x870 fs/btrfs/volumes.c:1181 Read of size 4 at addr ffff88805bfac930 by task syz.2.106/6322 CPU: 1 UID: 0 PID: 6322 Comm: syz.2.106 Not tainted 6.16.0-rc2-next-20250620-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: 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:1181 btrfs_close_devices+0xc5/0x500 fs/btrfs/volumes.c:1200 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:2059 [inline] btrfs_get_tree+0xa61/0x12d0 fs/btrfs/super.c:2093 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: 0033:0x7fe7e6b900ca 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:00007fe7e49f5e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fe7e49f5ef0 RCX: 00007fe7e6b900ca RDX: 0000200000005100 RSI: 0000200000000000 RDI: 00007fe7e49f5eb0 RBP: 0000200000005100 R08: 00007fe7e49f5ef0 R09: 0000000000000810 R10: 0000000000000810 R11: 0000000000000246 R12: 0000200000000000 R13: 00007fe7e49f5eb0 R14: 00000000000050f3 R15: 00002000000001c0 Allocated by task 6322: 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:4395 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:812 btrfs_scan_one_device+0x3fe/0x5b0 fs/btrfs/volumes.c:1486 btrfs_get_tree_super fs/btrfs/super.c:1857 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2059 [inline] btrfs_get_tree+0x441/0x12d0 fs/btrfs/super.c:2093 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 5881: 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:2416 [inline] slab_free mm/slub.c:4679 [inline] kfree+0x18e/0x440 mm/slub.c:4878 btrfs_free_stale_devices+0x561/0x5e0 fs/btrfs/volumes.c:563 btrfs_scan_one_device+0x3d6/0x5b0 fs/btrfs/volumes.c:1480 btrfs_control_ioctl+0x128/0x370 fs/btrfs/super.c:2242 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 ffff88805bfac800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 304 bytes inside of freed 512-byte region [ffff88805bfac800, ffff88805bfaca00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5bfac head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801a441c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801a441c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea00016feb01 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 3016, tgid 3016 (kworker/u8:9), ts 76124540472, free_ts 21173121612 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+0x21e4/0x22c0 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:2486 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2654 new_slab mm/slub.c:2708 [inline] ___slab_alloc+0xbeb/0x1410 mm/slub.c:3890 __slab_alloc mm/slub.c:3980 [inline] __slab_alloc_node mm/slub.c:4055 [inline] slab_alloc_node mm/slub.c:4216 [inline] __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4390 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] mca_alloc net/ipv6/mcast.c:884 [inline] __ipv6_dev_mc_inc+0x420/0xaf0 net/ipv6/mcast.c:975 addrconf_join_solict net/ipv6/addrconf.c:2242 [inline] addrconf_dad_begin net/ipv6/addrconf.c:4103 [inline] addrconf_dad_work+0x3d0/0x14b0 net/ipv6/addrconf.c:4231 process_one_work kernel/workqueue.c:3239 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3322 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3403 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 1 tgid 1 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706 __free_pages mm/page_alloc.c:5071 [inline] free_contig_range+0x1bd/0x4a0 mm/page_alloc.c:6927 destroy_args+0x7e/0x5d0 mm/debug_vm_pgtable.c:1009 debug_vm_pgtable+0x412/0x450 mm/debug_vm_pgtable.c:1389 do_one_initcall+0x233/0x820 init/main.c:1274 do_initcall_level+0x137/0x1f0 init/main.c:1336 do_initcalls+0x69/0xd0 init/main.c:1352 kernel_init_freeable+0x3d9/0x570 init/main.c:1584 kernel_init+0x1d/0x1d0 init/main.c:1474 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: ffff88805bfac800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805bfac880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805bfac900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805bfac980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805bfaca00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================