================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1550 Read of size 8 at addr ffff8801c8e862e0 by task syz-executor.0/2103 CPU: 0 PID: 2103 Comm: syz-executor.0 Not tainted 4.9.188+ #18 ffff8801a893f730 ffffffff81b64a21 0000000000000000 ffffea000723a000 ffff8801c8e862e0 0000000000000008 ffffffff81b38ed5 ffff8801a893f768 ffffffff8150b108 0000000000000000 ffff8801c8e862e0 ffff8801c8e862e0 Call Trace: [<00000000eb4aa147>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000eb4aa147>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000b91af8fc>] print_address_description+0x6f/0x23a mm/kasan/report.c:256 [<000000002556cf11>] kasan_report_error mm/kasan/report.c:355 [inline] [<000000002556cf11>] kasan_report mm/kasan/report.c:413 [inline] [<000000002556cf11>] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [<000000008af1b582>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:434 [<00000000e3b906fc>] disk_unblock_events+0x55/0x60 block/genhd.c:1550 [<0000000000390130>] __blkdev_get+0x6ba/0xeb0 fs/block_dev.c:1368 [<00000000bcc333b8>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [<000000000e211da2>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [<00000000254be151>] do_dentry_open+0x422/0xd20 fs/open.c:791 [<000000003ca8b502>] vfs_open+0x105/0x230 fs/open.c:904 [<00000000ac016f79>] do_last fs/namei.c:3457 [inline] [<00000000ac016f79>] path_openat+0xbf5/0x2f60 fs/namei.c:3581 [<00000000f428879b>] do_filp_open+0x1a1/0x280 fs/namei.c:3615 [<00000000f12d413c>] do_sys_open+0x2f0/0x610 fs/open.c:1097 [<000000000fb30c08>] SYSC_open fs/open.c:1115 [inline] [<000000000fb30c08>] SyS_open+0x2d/0x40 fs/open.c:1110 [<00000000c5751ed1>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000007ec3511b>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 5051: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:512 [inline] set_track mm/kasan/kasan.c:524 [inline] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616 kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601 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/0x7d0 drivers/block/loop.c:1849 loop_probe+0x154/0x180 drivers/block/loop.c:1956 kobj_lookup+0x221/0x410 drivers/base/map.c:124 get_gendisk+0x3c/0x2d0 block/genhd.c:716 __blkdev_get+0x356/0xeb0 fs/block_dev.c:1267 blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 do_dentry_open+0x422/0xd20 fs/open.c:791 vfs_open+0x105/0x230 fs/open.c:904 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:1097 SYSC_open fs/open.c:1115 [inline] SyS_open+0x2d/0x40 fs/open.c:1110 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 2103: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:512 [inline] set_track mm/kasan/kasan.c:524 [inline] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589 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+0xfc/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+0x422/0xd20 fs/open.c:791 vfs_open+0x105/0x230 fs/open.c:904 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:1097 SYSC_open fs/open.c:1115 [inline] SyS_open+0x2d/0x40 fs/open.c:1110 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801c8e85d80 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1376 bytes inside of 2048-byte region [ffff8801c8e85d80, ffff8801c8e86580) The buggy address belongs to the page: page:ffffea000723a000 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x4000000000010200(slab|head) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c8e86180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c8e86200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801c8e86280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801c8e86300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c8e86380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================