================================================================== BUG: KASAN: use-after-free in bdgrab+0x4c/0x50 fs/block_dev.c:929 Read of size 8 at addr ffff888065f50ba8 by task syz-executor.4/20389 CPU: 1 PID: 20389 Comm: syz-executor.4 Not tainted 5.12.0-rc1-next-20210302-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+0xfa/0x151 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:929 bdget_disk+0x91/0x180 block/genhd.c:802 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:1658 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: 0033:0x465ef9 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:00007f303cd10188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9 RDX: 0000000020000240 RSI: 0000000000001269 RDI: 0000000000000005 RBP: 00000000004bcd1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffff0884f8f R14: 00007f303cd10300 R15: 0000000000022000 Allocated by task 20138: 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:427 [inline] __kasan_slab_alloc+0x75/0x90 mm/kasan/common.c:460 kasan_slab_alloc include/linux/kasan.h:223 [inline] slab_post_alloc_hook mm/slab.h:516 [inline] slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] kmem_cache_alloc+0x15e/0x380 mm/slub.c:2920 bdev_alloc_inode+0x18/0x80 fs/block_dev.c:786 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:876 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:1658 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 9716: 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+0xf5/0x130 mm/kasan/common.c:367 kasan_slab_free include/linux/kasan.h:199 [inline] slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x72/0x1b0 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kmem_cache_free+0x8b/0x730 mm/slub.c:3177 i_callback+0x3f/0x70 fs/inode.c:223 rcu_do_batch kernel/rcu/tree.c:2559 [inline] rcu_core+0x722/0x1280 kernel/rcu/tree.c:2794 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345 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+0xb1/0x700 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:1658 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 The buggy address belongs to the object at ffff888065f50b80 which belongs to the cache bdev_cache of size 2792 The buggy address is located 40 bytes inside of 2792-byte region [ffff888065f50b80, ffff888065f51668) The buggy address belongs to the page: page:000000008b9e1b7e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x65f50 head:000000008b9e1b7e order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff8880109bdb40 raw: 0000000000000000 00000000800b000b 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888065f50a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888065f50b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888065f50b80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888065f50c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888065f50c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================