================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1550 Read of size 8 at addr ffff8801cba41660 by task syz-executor531/2164 CPU: 0 PID: 2164 Comm: syz-executor531 Not tainted 4.9.155+ #27 ffff8801cd847730 ffffffff81b47871 0000000000000000 ffffea00072e9000 ffff8801cba41660 0000000000000008 ffffffff81b19dd5 ffff8801cd847768 ffffffff81502825 0000000000000000 ffff8801cba41660 ffff8801cba41660 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x238 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report mm/kasan/report.c:412 [inline] [] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 [] disk_unblock_events+0x55/0x60 block/genhd.c:1550 [] __blkdev_get+0x6ba/0xeb0 fs/block_dev.c:1368 [] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [] do_dentry_open+0x3ef/0xc80 fs/open.c:766 [] vfs_open+0x105/0x230 fs/open.c:879 [] do_last fs/namei.c:3457 [inline] [] path_openat+0xbf5/0x2f60 fs/namei.c:3581 [] do_filp_open+0x1a1/0x280 fs/namei.c:3615 [] do_sys_open+0x2f0/0x610 fs/open.c:1072 [] SYSC_open fs/open.c:1090 [inline] [] SyS_open+0x2d/0x40 fs/open.c:1085 [] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 2164: 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.0+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:594 kmem_cache_alloc_trace+0x115/0x2d0 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+0x50/0x3c0 block/genhd.c:1294 alloc_disk+0x1b/0x20 block/genhd.c:1286 loop_add+0x37e/0x7b0 drivers/block/loop.c:1847 loop_control_ioctl drivers/block/loop.c:1982 [inline] loop_control_ioctl+0x132/0x2f0 drivers/block/loop.c:1964 vfs_ioctl fs/ioctl.c:43 [inline] file_ioctl fs/ioctl.c:493 [inline] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 SYSC_ioctl fs/ioctl.c:694 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 2164: 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+0xb0/0x190 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+0x255/0x330 block/genhd.c:1147 device_release+0x7d/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+0x150/0x260 lib/kobject.c:689 put_disk+0x23/0x30 block/genhd.c:1358 __blkdev_get+0x61a/0xeb0 fs/block_dev.c:1361 blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 do_dentry_open+0x3ef/0xc80 fs/open.c:766 vfs_open+0x105/0x230 fs/open.c:879 do_last fs/namei.c:3457 [inline] path_openat+0xbf5/0x2f60 fs/namei.c:3581 do_filp_open+0x1a1/0x280 fs/namei.c:3615 do_sys_open+0x2f0/0x610 fs/open.c:1072 SYSC_open fs/open.c:1090 [inline] SyS_open+0x2d/0x40 fs/open.c:1085 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801cba41100 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1376 bytes inside of 2048-byte region [ffff8801cba41100, ffff8801cba41900) The buggy address belongs to the page: page:ffffea00072e9000 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: ffff8801cba41500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801cba41580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801cba41600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801cba41680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801cba41700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================