BTRFS warning (device loop0): duplicate device /dev/loop4 devid 1 generation 7 scanned by syz-executor.4 (23589) BTRFS info (device loop0): disk space caching is enabled BTRFS info (device loop0): has skinny extents ================================================================== BUG: KASAN: use-after-free in btrfs_printk+0x34f/0x3d0 fs/btrfs/super.c:215 Read of size 8 at addr ffff888053335d20 by task systemd-udevd/22675 CPU: 0 PID: 22675 Comm: systemd-udevd Not tainted 4.19.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2fe lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433 btrfs_printk+0x34f/0x3d0 fs/btrfs/super.c:215 device_list_add.cold+0x1a0/0x376 fs/btrfs/volumes.c:860 btrfs_scan_one_device+0x33f/0xd00 fs/btrfs/volumes.c:1263 btrfs_control_ioctl+0x16b/0x2a0 fs/btrfs/super.c:2274 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f4a2c8df017 Code: 00 00 00 48 8b 05 81 7e 2b 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 7e 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007fffb8deafe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4a2c8df017 RDX: 00007fffb8deb000 RSI: 0000000090009427 RDI: 000000000000000f RBP: 00007fffb8deb000 R08: 0000000000000000 R09: 0000000000000090 R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000000f R13: 0000000000000000 R14: 000055720b0e1900 R15: 000055720b0e0ca0 Allocated by task 23514: __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node+0x4c/0x70 mm/slab.c:3696 kmalloc_node include/linux/slab.h:557 [inline] kvmalloc_node+0xb4/0xf0 mm/util.c:423 kvmalloc include/linux/mm.h:577 [inline] kvzalloc include/linux/mm.h:585 [inline] btrfs_mount_root+0x13f/0x1830 fs/btrfs/super.c:1556 mount_fs+0xa3/0x30c 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/0xa93 fs/btrfs/super.c:1681 mount_fs+0xa3/0x30c 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:2469 [inline] do_mount+0x113c/0x2f10 fs/namespace.c:2799 ksys_mount+0xcf/0x130 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xba/0x150 fs/namespace.c:3026 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 23514: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 kvfree+0x59/0x60 mm/util.c:452 deactivate_locked_super+0x94/0x160 fs/super.c:329 btrfs_mount_root+0x10a0/0x1830 fs/btrfs/super.c:1623 mount_fs+0xa3/0x30c 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/0xa93 fs/btrfs/super.c:1681 mount_fs+0xa3/0x30c 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:2469 [inline] do_mount+0x113c/0x2f10 fs/namespace.c:2799 ksys_mount+0xcf/0x130 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xba/0x150 fs/namespace.c:3026 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888053335700 which belongs to the cache kmalloc-8192 of size 8192 The buggy address is located 1568 bytes inside of 8192-byte region [ffff888053335700, ffff888053337700) The buggy address belongs to the page: page:ffffea00014ccd00 count:1 mapcount:0 mapping:ffff88813bff2080 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea0001813008 ffffea00014d8908 ffff88813bff2080 raw: 0000000000000000 ffff888053335700 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888053335c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888053335c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888053335d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888053335d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888053335e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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