================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1644 Read of size 8 at addr ffff888095c536c8 by task syz-executor128/9911 CPU: 0 PID: 9911 Comm: syz-executor128 Not tainted 4.14.134 #29 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+0x138/0x19c lib/dump_stack.c:53 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+0xa9/0x2af 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+0x7d6/0x1120 fs/block_dev.c:1556 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73b/0xeb0 fs/open.c:758 vfs_open+0x105/0x220 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 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x405751 RSP: 002b:00007fdeb013e980 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000405751 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fdeb013e990 RBP: 6666666666666667 R08: 000000000000000f R09: 00007fdeb013f700 R10: 00007fdeb013f9d0 R11: 0000000000000293 R12: 00000000006dbc4c R13: 00007fffa6f7b1ff R14: 00007fdeb013f9c0 R15: 000000000000002d Allocated by task 9911: 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_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 loop_add+0x3e7/0x850 drivers/block/loop.c:1858 loop_probe+0x136/0x160 drivers/block/loop.c:1965 kobj_lookup+0x21c/0x400 drivers/base/map.c:124 get_gendisk+0x3b/0x240 block/genhd.c:785 __blkdev_get+0x3af/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+0x73b/0xeb0 fs/open.c:758 vfs_open+0x105/0x220 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 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 9911: 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+0xf6/0x1a0 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+0x269/0x2f9 lib/kobject.c:692 put_disk+0x23/0x30 block/genhd.c:1452 __blkdev_get+0x73c/0x1120 fs/block_dev.c:1549 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73b/0xeb0 fs/open.c:758 vfs_open+0x105/0x220 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 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff888095c53140 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1416 bytes inside of 2048-byte region [ffff888095c53140, ffff888095c53940) The buggy address belongs to the page: page:ffffea0002571480 count:1 mapcount:0 mapping:ffff888095c52040 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffff888095c52040 0000000000000000 0000000100000003 raw: ffffea00022cc920 ffffea0001f720a0 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888095c53580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095c53600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888095c53680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888095c53700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095c53780: fb fb fb fb fb fb fb fb 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