================================================================== BUG: KASAN: use-after-free in bdgrab+0x4c/0x50 fs/block_dev.c:938 Read of size 8 at addr ffff888016fd50a8 by task syz-executor.5/10383 CPU: 0 PID: 10383 Comm: syz-executor.5 Not tainted 5.12.0-rc4-next-20210326-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 bdgrab+0x4c/0x50 fs/block_dev.c:938 bdget_disk+0x91/0x180 block/genhd.c:800 bdev_del_partition+0x41/0x110 block/partitions/core.c:460 blkpg_do_ioctl+0x2e8/0x340 block/ioctl.c:33 blkpg_ioctl block/ioctl.c:60 [inline] blkdev_ioctl+0x577/0x6d0 block/ioctl.c:548 block_ioctl+0xf9/0x140 fs/block_dev.c:1667 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466459 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0327e2e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000466459 RDX: 0000000020000240 RSI: 0000000000001269 RDI: 0000000000000004 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffec0f4cacf R14: 00007f0327e2e300 R15: 0000000000022000 Allocated by task 10191: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:461 kasan_slab_alloc include/linux/kasan.h:236 [inline] slab_post_alloc_hook mm/slab.h:525 [inline] slab_alloc_node mm/slub.c:2909 [inline] slab_alloc mm/slub.c:2917 [inline] kmem_cache_alloc+0x212/0x390 mm/slub.c:2922 bdev_alloc_inode+0x18/0x80 fs/block_dev.c:795 alloc_inode+0x61/0x230 fs/inode.c:234 new_inode_pseudo fs/inode.c:928 [inline] new_inode+0x27/0x2f0 fs/inode.c:957 bdev_alloc+0x20/0x2f0 fs/block_dev.c:885 add_partition+0x1ab/0x880 block/partitions/core.c:346 bdev_add_partition+0xb6/0x130 block/partitions/core.c:449 blkpg_do_ioctl+0x2d0/0x340 block/ioctl.c:43 blkpg_ioctl block/ioctl.c:60 [inline] blkdev_ioctl+0x577/0x6d0 block/ioctl.c:548 block_ioctl+0xf9/0x140 fs/block_dev.c:1667 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 375: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357 ____kasan_slab_free mm/kasan/common.c:360 [inline] ____kasan_slab_free mm/kasan/common.c:325 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:212 [inline] slab_free_hook mm/slub.c:1578 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1603 slab_free mm/slub.c:3163 [inline] kmem_cache_free+0x8a/0x730 mm/slub.c:3179 i_callback+0x3f/0x70 fs/inode.c:223 rcu_do_batch kernel/rcu/tree.c:2559 [inline] rcu_core+0x7ab/0x13b0 kernel/rcu/tree.c:2794 __do_softirq+0x29b/0x9f6 kernel/softirq.c:559 Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345 __call_rcu kernel/rcu/tree.c:3039 [inline] call_rcu+0xb1/0x750 kernel/rcu/tree.c:3114 destroy_inode+0x129/0x1b0 fs/inode.c:289 iput_final fs/inode.c:1654 [inline] iput.part.0+0x57e/0x810 fs/inode.c:1680 iput+0x58/0x70 fs/inode.c:1670 bdev_del_partition+0xc8/0x110 block/partitions/core.c:479 blkpg_do_ioctl+0x2e8/0x340 block/ioctl.c:33 blkpg_ioctl block/ioctl.c:60 [inline] blkdev_ioctl+0x577/0x6d0 block/ioctl.c:548 block_ioctl+0xf9/0x140 fs/block_dev.c:1667 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Second to last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345 __call_rcu kernel/rcu/tree.c:3039 [inline] call_rcu+0xb1/0x750 kernel/rcu/tree.c:3114 destroy_inode+0x129/0x1b0 fs/inode.c:289 iput_final fs/inode.c:1654 [inline] iput.part.0+0x57e/0x810 fs/inode.c:1680 iput+0x58/0x70 fs/inode.c:1670 disk_release+0x196/0x250 block/genhd.c:1213 device_release+0x9f/0x240 drivers/base/core.c:2143 kobject_cleanup lib/kobject.c:705 [inline] kobject_release lib/kobject.c:736 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x540 lib/kobject.c:753 put_device+0x1b/0x30 drivers/base/core.c:3376 put_disk+0x44/0x60 block/genhd.c:1415 do_floppy_init drivers/block/floppy.c:4826 [inline] floppy_async_init+0x1ffe/0x202d drivers/block/floppy.c:4834 async_run_entry_fn+0x9d/0x550 kernel/async.c:127 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 The buggy address belongs to the object at ffff888016fd5080 which belongs to the cache bdev_cache of size 2784 The buggy address is located 40 bytes inside of 2784-byte region [ffff888016fd5080, ffff888016fd5b60) The buggy address belongs to the page: page:ffffea00005bf400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16fd0 head:ffffea00005bf400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff8880109bdc80 raw: 0000000000000000 00000000800b000b 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888016fd4f80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888016fd5000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888016fd5080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888016fd5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888016fd5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================