================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1543 Read of size 8 at addr ffff8800a409c968 by task blkid/14574 CPU: 0 PID: 14574 Comm: blkid Not tainted 4.4.174+ #4 0000000000000000 eb552dbbbf7115f1 ffff8800b478f730 ffffffff81aad1a1 0000000000000000 ffffea0002902600 ffff8800a409c968 0000000000000008 0000000000000000 ffff8800b478f768 ffffffff81490120 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x21b mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report mm/kasan/report.c:408 [inline] [] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429 [] disk_unblock_events+0x55/0x60 block/genhd.c:1543 [] __blkdev_get+0x70c/0xdf0 fs/block_dev.c:1297 [] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353 [] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_sys_open+0x2f8/0x600 fs/open.c:1038 [] SYSC_open fs/open.c:1056 [inline] [] SyS_open+0x2d/0x40 fs/open.c:1051 [] entry_SYSCALL_64_fastpath+0x1e/0x9a Allocated by task 14560: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] 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+0x123/0x2d0 mm/slub.c:2642 [] kmem_cache_alloc_node_trace include/linux/slab.h:367 [inline] [] kmalloc_node include/linux/slab.h:514 [inline] [] kzalloc_node include/linux/slab.h:631 [inline] [] alloc_disk_node+0x50/0x3c0 block/genhd.c:1282 [] alloc_disk+0x1b/0x20 block/genhd.c:1274 [] loop_add+0x380/0x830 drivers/block/loop.c:1857 [] loop_control_ioctl+0x138/0x2f0 drivers/block/loop.c:1988 [] vfs_ioctl fs/ioctl.c:43 [inline] [] file_ioctl fs/ioctl.c:470 [inline] [] do_vfs_ioctl+0x6e7/0xfa0 fs/ioctl.c:605 [] SYSC_ioctl fs/ioctl.c:622 [inline] [] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613 [] entry_SYSCALL_64_fastpath+0x1e/0x9a Freed by task 14574: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] 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:1383 [inline] [] slab_free_freelist_hook mm/slub.c:1405 [inline] [] slab_free mm/slub.c:2859 [inline] [] kfree+0xf4/0x310 mm/slub.c:3749 [] disk_release+0x255/0x330 block/genhd.c:1118 [] 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+0x14c/0x260 lib/kobject.c:689 [] put_disk+0x23/0x30 block/genhd.c:1346 [] __blkdev_get+0x66c/0xdf0 fs/block_dev.c:1290 [] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353 [] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_sys_open+0x2f8/0x600 fs/open.c:1038 [] SYSC_open fs/open.c:1056 [inline] [] SyS_open+0x2d/0x40 fs/open.c:1051 [] entry_SYSCALL_64_fastpath+0x1e/0x9a The buggy address belongs to the object at ffff8800a409c400 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1384 bytes inside of 2048-byte region [ffff8800a409c400, ffff8800a409cc00) The buggy address belongs to the page: audit: type=1400 audit(1575461642.314:20): avc: denied { sigchld } for pid=2121 comm="syz-executor.3" scontext=system_u:object_r:unlabeled_t:s0 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=process permissive=1 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access[ 203.307604] ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2121 at kernel/sched/core.c:7941 __might_sleep+0x138/0x1a0 kernel/sched/core.c:7941() do not call blocking ops when !TASK_RUNNING; state=1 set at [] do_wait+0x265/0xa00 kernel/exit.c:1511