================================================================== BUG: KASAN: use-after-free in caching_kthread+0x871/0x970 fs/btrfs/inode-map.c:31 Read of size 8 at addr ffff8880928ae330 by task btrfs-ino-cache/29608 CPU: 0 PID: 29608 Comm: btrfs-ino-cache Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433 caching_kthread+0x871/0x970 fs/btrfs/inode-map.c:31 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 29509: kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] btrfs_alloc_root fs/btrfs/disk-io.c:1220 [inline] btrfs_read_tree_root+0x94/0x560 fs/btrfs/disk-io.c:1421 btrfs_read_fs_root fs/btrfs/disk-io.c:1467 [inline] btrfs_get_fs_root+0x239/0x890 fs/btrfs/disk-io.c:1601 btrfs_read_fs_root_no_name fs/btrfs/disk-io.h:80 [inline] open_ctree+0x469c/0x61e0 fs/btrfs/disk-io.c:3181 btrfs_fill_super fs/btrfs/super.c:1209 [inline] btrfs_mount_root+0x12e5/0x1830 fs/btrfs/super.c:1613 mount_fs+0xa3/0x310 fs/super.c:1261 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961 vfs_kern_mount+0x3c/0x60 fs/namespace.c:951 btrfs_mount+0x23a/0xaa0 fs/btrfs/super.c:1681 mount_fs+0xa3/0x310 fs/super.c:1261 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2492 [inline] do_mount+0x115c/0x2f50 fs/namespace.c:2822 ksys_mount+0xcf/0x130 fs/namespace.c:3038 __do_sys_mount fs/namespace.c:3052 [inline] __se_sys_mount fs/namespace.c:3049 [inline] __x64_sys_mount+0xba/0x150 fs/namespace.c:3049 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8159: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 btrfs_put_fs_root fs/btrfs/disk-io.h:111 [inline] btrfs_free_fs_root+0x1e6/0x260 fs/btrfs/disk-io.c:3861 btrfs_free_fs_roots+0x2ef/0x4d0 fs/btrfs/disk-io.c:2092 close_ctree+0x306/0x850 fs/btrfs/disk-io.c:4017 generic_shutdown_super+0x144/0x370 fs/super.c:456 kill_anon_super+0x36/0x60 fs/super.c:1032 btrfs_kill_super+0x49/0x550 fs/btrfs/super.c:2221 deactivate_locked_super+0x94/0x160 fs/super.c:329 deactivate_super+0x174/0x1a0 fs/super.c:360 cleanup_mnt+0x1a8/0x290 fs/namespace.c:1098 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880928ae140 which belongs to the cache kmalloc-4096 of size 4096 The buggy address is located 496 bytes inside of 4096-byte region [ffff8880928ae140, ffff8880928af140) The buggy address belongs to the page: page:ffffea00024a2b80 count:1 mapcount:0 mapping:ffff88813bff0dc0 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea00025b5808 ffffea0002a5ba08 ffff88813bff0dc0 raw: 0000000000000000 ffff8880928ae140 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880928ae200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880928ae280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880928ae300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880928ae380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880928ae400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue