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BUG: KASAN: use-after-free in blkdev_bio_end_io+0x37e/0x430 fs/block_dev.c:301
Read of size 1 at addr ffff8880a5a76914 by task ksoftirqd/0/9

CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.3.0-rc3+ #70
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x2f8 lib/dump_stack.c:113
 print_address_description+0x75/0x5b0 mm/kasan/report.c:351
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:482
 kasan_report+0x26/0x50 mm/kasan/common.c:612
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129
 blkdev_bio_end_io+0x37e/0x430 fs/block_dev.c:301
 bio_endio+0x4ff/0x570 block/bio.c:1830
 req_bio_endio block/blk-core.c:239 [inline]
 blk_update_request+0x385/0xf80 block/blk-core.c:1424
 blk_mq_end_request+0x42/0x80 block/blk-mq.c:557
 end_cmd+0xeb/0x2d0 drivers/block/null_blk_main.c:622
 null_complete_rq+0x1c/0x20 drivers/block/null_blk_main.c:649
 blk_done_softirq+0x312/0x370 block/blk-softirq.c:37
 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:778
 run_ksoftirqd+0x64/0xf0 kernel/softirq.c:603
 smpboot_thread_fn+0x5b3/0x9a0 kernel/smpboot.c:165
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 32731:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:487
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:495
 slab_post_alloc_hook mm/slab.h:520 [inline]
 slab_alloc mm/slab.c:3319 [inline]
 kmem_cache_alloc+0x1f5/0x2e0 mm/slab.c:3483
 mempool_alloc_slab+0x4d/0x70 mm/mempool.c:513
 mempool_alloc+0x104/0x5e0 mm/mempool.c:393
 bio_alloc_bioset+0x1b0/0x5f0 block/bio.c:477
 __blkdev_direct_IO+0x244/0x1340 fs/block_dev.c:363
 blkdev_direct_IO+0xbe/0xd0 fs/block_dev.c:515
 generic_file_read_iter+0x1ad3/0x21b0 mm/filemap.c:2323
 blkdev_read_iter+0x12e/0x140 fs/block_dev.c:2046
 call_read_iter include/linux/fs.h:1864 [inline]
 aio_read+0x31f/0x400 fs/aio.c:1543
 __io_submit_one fs/aio.c:1817 [inline]
 io_submit_one+0x6eb/0x1970 fs/aio.c:1862
 __do_sys_io_submit fs/aio.c:1921 [inline]
 __se_sys_io_submit+0x12f/0x240 fs/aio.c:1891
 __x64_sys_io_submit+0x7b/0x90 fs/aio.c:1891
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:449
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457
 __cache_free mm/slab.c:3425 [inline]
 kmem_cache_free+0x81/0xf0 mm/slab.c:3693
 mempool_free_slab+0x1d/0x30 mm/mempool.c:520
 mempool_free+0xd5/0x350 mm/mempool.c:502
 bio_put+0x35a/0x420 block/bio.c:253
 bio_check_pages_dirty+0x404/0x4e0 block/bio.c:1703
 blkdev_bio_end_io+0x345/0x430 fs/block_dev.c:330
 bio_endio+0x4ff/0x570 block/bio.c:1830
 req_bio_endio block/blk-core.c:239 [inline]
 blk_update_request+0x385/0xf80 block/blk-core.c:1424
 blk_mq_end_request+0x42/0x80 block/blk-mq.c:557
 end_cmd+0xeb/0x2d0 drivers/block/null_blk_main.c:622
 null_complete_rq+0x1c/0x20 drivers/block/null_blk_main.c:649
 blk_done_softirq+0x312/0x370 block/blk-softirq.c:37
 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:778

The buggy address belongs to the object at ffff8880a5a76900
 which belongs to the cache bio-1 of size 216
The buggy address is located 20 bytes inside of
 216-byte region [ffff8880a5a76900, ffff8880a5a769d8)
The buggy address belongs to the page:
page:ffffea0002969d80 refcount:1 mapcount:0 mapping:ffff88821b3c68c0 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffff8880a5a73248 ffffea0000dd78c8 ffff88821b3c68c0
raw: 0000000000000000 ffff8880a5a76040 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a5a76800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a5a76880: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a5a76900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8880a5a76980: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
 ffff8880a5a76a00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
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