audit: type=1400 audit(1572119059.351:5): avc: denied { associate } for pid=2087 comm="syz-executor.3" name="syz3" 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+0x55/0x60 block/genhd.c:1550 Read of size 8 at addr ffff8801d69362e0 by task syz-executor.0/2081 CPU: 0 PID: 2081 Comm: syz-executor.0 Not tainted 4.9.194+ #0 ffff8801ce697730 ffffffff81b67001 0000000000000000 ffffea00075a4c00 ffff8801d69362e0 0000000000000008 ffffffff81b3b4b5 ffff8801ce697768 ffffffff8150c4f1 0000000000000000 ffff8801d69362e0 ffff8801d69362e0 Call Trace: [<000000005a4955a1>] __dump_stack lib/dump_stack.c:15 [inline] [<000000005a4955a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000d2f20722>] print_address_description+0x6f/0x23a mm/kasan/report.c:256 [<00000000dccef32b>] kasan_report_error mm/kasan/report.c:355 [inline] [<00000000dccef32b>] kasan_report mm/kasan/report.c:413 [inline] [<00000000dccef32b>] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [<00000000a6d0656d>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:434 [<00000000a3f4b270>] disk_unblock_events+0x55/0x60 block/genhd.c:1550 [<000000003722ef34>] __blkdev_get+0x6ba/0xeb0 fs/block_dev.c:1368 [<0000000041c56228>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [<00000000489ee90a>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [<000000005f9c4880>] do_dentry_open+0x422/0xd20 fs/open.c:791 [<00000000209eeb47>] vfs_open+0x105/0x230 fs/open.c:904 [<00000000bb950d82>] do_last fs/namei.c:3541 [inline] [<00000000bb950d82>] path_openat+0xbf5/0x2f60 fs/namei.c:3665 [<00000000bc2b125a>] do_filp_open+0x1a1/0x280 fs/namei.c:3699 [<000000009dd74d65>] do_sys_open+0x2f0/0x610 fs/open.c:1097 [<00000000fc3cc8cf>] SYSC_open fs/open.c:1115 [inline] [<00000000fc3cc8cf>] SyS_open+0x2d/0x40 fs/open.c:1110 [<00000000b5d4871d>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000005de93085>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 2081: 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:3541 [inline] path_openat+0xbf5/0x2f60 fs/namei.c:3665 do_filp_open+0x1a1/0x280 fs/namei.c:3699 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 2081: 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:3541 [inline] path_openat+0xbf5/0x2f60 fs/namei.c:3665 do_filp_open+0x1a1/0x280 fs/namei.c:3699 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 ffff8801d6935d80 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1376 bytes inside of 2048-byte region [ffff8801d6935d80, ffff8801d6936580) The buggy address belongs to the page: page:ffffea00075a4c00 count:1 mapcount:0 mapping: (null) index:0xffff8801d6930880 compound_mapcount: 0 flags: 0x4000000000010200(slab|head) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d6936180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d6936200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d6936280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d6936300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d6936380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================