md: md0 stopped. md: md0 stopped. md: md0 stopped. ================================================================== md: md0 stopped. BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1644 md: md0 stopped. Read of size 8 at addr ffff88809a86e7c8 by task syz-executor889/7287 CPU: 0 PID: 7287 Comm: syz-executor889 Not tainted 4.14.115 #5 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: md: md0 stopped. __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x138/0x19c lib/dump_stack.c:53 md: md0 stopped. print_address_description.cold+0x7c/0x1dc 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+0x11e/0x2db mm/kasan/report.c:393 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 disk_unblock_events+0x55/0x60 block/genhd.c:1644 __blkdev_get+0x7d8/0x1120 fs/block_dev.c:1556 md: md0 stopped. blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 md: md0 stopped. do_dentry_open+0x73e/0xeb0 fs/open.c:758 md: md0 stopped. vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 md: md0 stopped. md: md0 stopped. md: md0 stopped. do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_openat fs/open.c:1092 [inline] SyS_openat+0x30/0x40 fs/open.c:1086 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x441259 RSP: 002b:00007ffc28007d78 EFLAGS: 00000246 md: md0 stopped. ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441259 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c RBP: 00000000000120a8 R08: 0000000000000004 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401fd0 R13: 0000000000402060 R14: 0000000000000000 R15: 0000000000000000 md: md0 stopped. Allocated by task 1: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 md: md0 stopped. save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kmem_cache_alloc_node_trace+0x153/0x770 mm/slab.c:3661 kmalloc_node include/linux/slab.h:526 [inline] kzalloc_node include/linux/slab.h:672 [inline] alloc_disk_node+0x64/0x3e0 block/genhd.c:1387 alloc_disk+0x1b/0x20 block/genhd.c:1371 md: md0 stopped. md_alloc+0x219/0x840 drivers/md/md.c:5313 md_probe+0x31/0x40 drivers/md/md.c:5370 md: md0 stopped. kobj_lookup+0x221/0x410 drivers/base/map.c:124 get_gendisk+0x3b/0x240 block/genhd.c:785 md: md0 stopped. __blkdev_get+0x3b1/0x1120 fs/block_dev.c:1451 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 autodetect_raid init/do_mounts_md.c:297 [inline] md_run_setup+0x7a/0xad init/do_mounts_md.c:311 prepare_namespace+0x4a/0x21d init/do_mounts.c:567 md: md0 stopped. kernel_init_freeable+0x51a/0x538 init/main.c:1092 kernel_init+0x12/0x162 init/main.c:999 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Freed by task 7287: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 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+0xcc/0x270 mm/slab.c:3815 disk_release+0x24b/0x2d0 block/genhd.c:1230 device_release+0xfa/0x1b0 drivers/base/core.c:822 kobject_cleanup lib/kobject.c:646 [inline] kobject_release lib/kobject.c:675 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put.cold+0x26f/0x2ff lib/kobject.c:692 put_disk+0x23/0x30 block/genhd.c:1452 __blkdev_get+0x73e/0x1120 fs/block_dev.c:1549 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 md: md0 stopped. do_dentry_open+0x73e/0xeb0 fs/open.c:758 md: md0 stopped. vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_openat fs/open.c:1092 [inline] SyS_openat+0x30/0x40 fs/open.c:1086 md: md0 stopped. do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff88809a86e240 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1416 bytes inside of 2048-byte region [ffff88809a86e240, ffff88809a86ea40) md: md0 stopped. The buggy address belongs to the page: page:ffffea00026a1b80 count:1 mapcount:0 mapping:ffff88809a86e240 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffff88809a86e240 0000000000000000 0000000100000003 raw: ffffea00026a1520 ffffea0002696720 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected md: md0 stopped. Memory state around the buggy address: ffff88809a86e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809a86e700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809a86e780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809a86e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809a86e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== md: md0 stopped.