audit: type=1400 audit(1545821758.363:8): avc: denied { associate } for pid=2086 comm="syz-executor0" name="syz0" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 ================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 block/genhd.c:1550 Read of size 8 at addr ffff8801d0150de0 by task blkid/3839 CPU: 0 PID: 3839 Comm: blkid Not tainted 4.9.141+ #1 ffff8801c5b1f6f8 ffffffff81b42e79 ffffea0007405400 ffff8801d0150de0 0000000000000000 ffff8801d0150de0 0000000000000000 ffff8801c5b1f730 ffffffff815009b8 ffff8801d0150de0 0000000000000008 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x6c/0x234 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 [] disk_unblock_events+0x51/0x60 block/genhd.c:1550 [] __blkdev_get+0x6b6/0xd60 fs/block_dev.c:1360 [] blkdev_get+0x2da/0x920 fs/block_dev.c:1416 [] blkdev_open+0x1a5/0x250 fs/block_dev.c:1571 [] do_dentry_open+0x3ef/0xc90 fs/open.c:766 [] vfs_open+0x11c/0x210 fs/open.c:879 [] do_last fs/namei.c:3410 [inline] [] path_openat+0x542/0x2790 fs/namei.c:3534 [] do_filp_open+0x197/0x270 fs/namei.c:3568 [] do_sys_open+0x30d/0x5c0 fs/open.c:1072 [] SYSC_open fs/open.c:1090 [inline] [] SyS_open+0x2d/0x40 fs/open.c:1085 [] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 3820: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:594 kmem_cache_alloc_trace+0x117/0x2e0 mm/slub.c:2742 kmem_cache_alloc_node_trace include/linux/slab.h:381 [inline] kmalloc_node include/linux/slab.h:528 [inline] kzalloc_node include/linux/slab.h:647 [inline] alloc_disk_node+0x54/0x3a0 block/genhd.c:1294 alloc_disk+0x18/0x20 block/genhd.c:1286 loop_add+0x368/0x7a0 drivers/block/loop.c:1817 loop_probe+0x14f/0x180 drivers/block/loop.c:1924 kobj_lookup+0x223/0x410 drivers/base/map.c:124 get_gendisk+0x39/0x2d0 block/genhd.c:716 bd_start_claiming fs/block_dev.c:926 [inline] blkdev_get+0xf6/0x920 fs/block_dev.c:1409 blkdev_open+0x1a5/0x250 fs/block_dev.c:1571 do_dentry_open+0x3ef/0xc90 fs/open.c:766 vfs_open+0x11c/0x210 fs/open.c:879 do_last fs/namei.c:3410 [inline] path_openat+0x542/0x2790 fs/namei.c:3534 do_filp_open+0x197/0x270 fs/namei.c:3568 do_sys_open+0x30d/0x5c0 fs/open.c:1072 SYSC_open fs/open.c:1090 [inline] SyS_open+0x2d/0x40 fs/open.c:1085 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 3839: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kfree+0xfb/0x310 mm/slub.c:3878 disk_release+0x259/0x330 block/genhd.c:1147 device_release+0x7e/0x220 drivers/base/core.c:247 kobject_cleanup lib/kobject.c:643 [inline] kobject_release lib/kobject.c:672 [inline] kref_sub include/linux/kref.h:73 [inline] kref_put include/linux/kref.h:98 [inline] kobject_put+0x148/0x250 lib/kobject.c:689 put_disk+0x23/0x30 block/genhd.c:1358 __blkdev_get+0x616/0xd60 fs/block_dev.c:1353 blkdev_get+0x2da/0x920 fs/block_dev.c:1416 blkdev_open+0x1a5/0x250 fs/block_dev.c:1571 do_dentry_open+0x3ef/0xc90 fs/open.c:766 vfs_open+0x11c/0x210 fs/open.c:879 do_last fs/namei.c:3410 [inline] path_openat+0x542/0x2790 fs/namei.c:3534 do_filp_open+0x197/0x270 fs/namei.c:3568 do_sys_open+0x30d/0x5c0 fs/open.c:1072 SYSC_open fs/open.c:1090 [inline] SyS_open+0x2d/0x40 fs/open.c:1085 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801d0150880 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1376 bytes inside of 2048-byte region [ffff8801d0150880, ffff8801d0151080) The buggy address belongs to the page: page:ffffea0007405400 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x4000000000004080(slab|head) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d0150c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d0150d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d0150d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d0150e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d0150e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================