================================================================== BUG: KASAN: use-after-free in bdev_nr_sectors include/linux/genhd.h:264 [inline] BUG: KASAN: use-after-free in disk_part_iter_next+0x4c7/0x560 block/genhd.c:204 Read of size 8 at addr ffff888016b2a2a8 by task syz-executor.0/8468 CPU: 0 PID: 8468 Comm: syz-executor.0 Not tainted 5.10.0-rc6-next-20201207-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+0x107/0x163 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230 __kasan_report mm/kasan/report.c:396 [inline] kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413 bdev_nr_sectors include/linux/genhd.h:264 [inline] disk_part_iter_next+0x4c7/0x560 block/genhd.c:204 blk_drop_partitions+0x10a/0x180 block/partitions/core.c:541 bdev_disk_changed+0x238/0x430 fs/block_dev.c:1228 __loop_clr_fd+0xb71/0xe00 drivers/block/loop.c:1268 loop_clr_fd drivers/block/loop.c:1334 [inline] lo_ioctl+0x3b7/0x1720 drivers/block/loop.c:1692 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:576 block_ioctl+0xf9/0x140 fs/block_dev.c:1649 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+0x44/0xa9 RIP: 0033:0x45df67 Code: 48 83 c4 08 48 89 d8 5b 5d c3 66 0f 1f 84 00 00 00 00 00 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb 92 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 6d b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffb5c63ac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045df67 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003 RBP: 000000000000001c R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffb5c63b00 R14: 00007fffb5c63b10 R15: 0000000000050fa4 Allocated by task 10168: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_set_track mm/kasan/common.c:47 [inline] set_alloc_info mm/kasan/common.c:405 [inline] ____kasan_kmalloc mm/kasan/common.c:436 [inline] ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:408 kasan_slab_alloc include/linux/kasan.h:205 [inline] slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc_node mm/slub.c:2903 [inline] slab_alloc mm/slub.c:2911 [inline] kmem_cache_alloc+0x155/0x380 mm/slub.c:2916 bdev_alloc_inode+0x18/0x40 fs/block_dev.c:777 alloc_inode+0x61/0x230 fs/inode.c:233 new_inode_pseudo fs/inode.c:927 [inline] new_inode+0x27/0x2f0 fs/inode.c:956 bdev_alloc+0x20/0x340 fs/block_dev.c:864 add_partition+0x1ad/0x8e0 block/partitions/core.c:345 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:541 block_ioctl+0xf9/0x140 fs/block_dev.c:1649 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+0x44/0xa9 Freed by task 10147: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_set_track+0x1c/0x30 mm/kasan/common.c:47 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:355 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:188 [inline] slab_free_hook mm/slub.c:1548 [inline] slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1586 slab_free mm/slub.c:3157 [inline] kmem_cache_free+0x82/0x360 mm/slub.c:3173 i_callback+0x3f/0x70 fs/inode.c:222 rcu_do_batch kernel/rcu/tree.c:2502 [inline] rcu_core+0x735/0x1020 kernel/rcu/tree.c:2737 __do_softirq+0x2b7/0xa76 kernel/softirq.c:343 Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_record_aux_stack+0xdc/0x100 mm/kasan/generic.c:343 __call_rcu kernel/rcu/tree.c:2987 [inline] call_rcu+0xbb/0x810 kernel/rcu/tree.c:3062 destroy_inode+0x129/0x1b0 fs/inode.c:288 iput_final fs/inode.c:1651 [inline] iput.part.0+0x41e/0x840 fs/inode.c:1677 iput+0x58/0x70 fs/inode.c:1667 disk_part_iter_exit block/genhd.c:232 [inline] disk_part_iter_next+0x9a/0x560 block/genhd.c:200 blk_drop_partitions+0x10a/0x180 block/partitions/core.c:541 bdev_disk_changed+0x238/0x430 fs/block_dev.c:1228 loop_reread_partitions+0x29/0x50 drivers/block/loop.c:655 loop_set_status+0x735/0x1040 drivers/block/loop.c:1416 loop_set_status64 drivers/block/loop.c:1536 [inline] lo_ioctl+0x900/0x1720 drivers/block/loop.c:1704 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:576 block_ioctl+0xf9/0x140 fs/block_dev.c:1649 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+0x44/0xa9 The buggy address belongs to the object at ffff888016b2a280 which belongs to the cache bdev_cache of size 2808 The buggy address is located 40 bytes inside of 2808-byte region [ffff888016b2a280, ffff888016b2ad78) The buggy address belongs to the page: page:00000000e82493c7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16b28 head:00000000e82493c7 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff8880109c0b40 raw: 0000000000000000 00000000800b000b 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888016b2a180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc ffff888016b2a200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888016b2a280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888016b2a300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888016b2a380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================