================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x4b/0x50 block/genhd.c:1644 Read of size 8 at addr ffff8880583928c8 by task syz-executor.2/8790 CPU: 1 PID: 8790 Comm: syz-executor.2 Not tainted 4.14.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393 disk_unblock_events+0x4b/0x50 block/genhd.c:1644 __blkdev_get+0x79c/0x10d0 fs/block_dev.c:1556 blkdev_get+0x84/0x8a0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x732/0xe90 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3428 [inline] path_openat+0x8ca/0x3c50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 md: invalid raid superblock magic on mtdblock0 do_sys_open+0x29d/0x3f0 fs/open.c:1084 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c479 RSP: 002b:00007f203d16cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f203d16d6d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 0000000020000080 RDI: ffffffffffffff9c RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000007a7 R14: 00000000004ca185 R15: 000000000076bf2c Allocated by task 8744: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 kmem_cache_alloc_node_trace+0x15a/0x7b0 mm/slab.c:3661 kmalloc_node include/linux/slab.h:526 [inline] kzalloc_node include/linux/slab.h:672 [inline] alloc_disk_node+0x5d/0x3d0 block/genhd.c:1387 md_alloc+0x20e/0x810 drivers/md/md.c:5322 md_probe+0x28/0x40 drivers/md/md.c:5379 kobj_lookup+0x221/0x410 drivers/base/map.c:124 get_gendisk+0x36/0x240 block/genhd.c:785 __blkdev_get+0x384/0x10d0 fs/block_dev.c:1451 blkdev_get+0x84/0x8a0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x732/0xe90 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3428 [inline] path_openat+0x8ca/0x3c50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x29d/0x3f0 fs/open.c:1084 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 8790: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 md: mtdblock0 does not have a valid v0.0 superblock, not importing! device_release+0xf0/0x1a0 drivers/base/core.c:831 kobject_cleanup lib/kobject.c:646 [inline] kobject_release lib/kobject.c:675 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put+0x13e/0x1f0 lib/kobject.c:692 put_disk+0x1f/0x30 block/genhd.c:1452 __blkdev_get+0x707/0x10d0 fs/block_dev.c:1549 blkdev_get+0x84/0x8a0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x732/0xe90 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3428 [inline] path_openat+0x8ca/0x3c50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x29d/0x3f0 fs/open.c:1084 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff888058392340 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1416 bytes inside of 2048-byte region [ffff888058392340, ffff888058392b40) The buggy address belongs to the page: page:ffffea000160e480 count:1 mapcount:0 mapping:ffff888058392340 index:0xffff888058393440 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff888058392340 ffff888058393440 0000000100000002 raw: ffffea0001773120 ffffea0002a65520 ffff88812fe56c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888058392780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888058392800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb md: md_import_device returned -22 >ffff888058392880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888058392900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888058392980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================