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BUG: KMSAN: uninit-value in blkdev_bio_end_io+0x20e/0x730 fs/block_dev.c:306
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.3.0-rc3+ #16
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+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
 blkdev_bio_end_io+0x20e/0x730 fs/block_dev.c:306
 bio_endio+0xa5e/0xbe0 block/bio.c:1845
 req_bio_endio block/blk-core.c:239 [inline]
 blk_update_request+0xcbc/0x1fa0 block/blk-core.c:1424
 blk_mq_end_request+0x9e/0x120 block/blk-mq.c:557
 end_cmd+0x114/0x3e0 drivers/block/null_blk_main.c:622
 null_complete_rq+0x3e/0x50 drivers/block/null_blk_main.c:649
 blk_done_softirq+0x360/0x4e0 block/blk-softirq.c:37
 __do_softirq+0x4a1/0x83a kernel/softirq.c:293
 run_ksoftirqd+0x25/0x40 kernel/softirq.c:607
 smpboot_thread_fn+0x4a3/0x990 kernel/smpboot.c:165
 kthread+0x4b5/0x4f0 kernel/kthread.c:256
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:187 [inline]
 kmsan_internal_poison_shadow+0x53/0xa0 mm/kmsan/kmsan.c:146
 kmsan_slab_free+0x8d/0x100 mm/kmsan/kmsan_hooks.c:195
 slab_free_freelist_hook mm/slub.c:1472 [inline]
 slab_free mm/slub.c:3038 [inline]
 kmem_cache_free+0x2d1/0x2b70 mm/slub.c:3054
 mempool_free_slab+0x5d/0x70 mm/mempool.c:520
 mempool_free+0x144/0x430 mm/mempool.c:502
 bio_put+0x9c0/0xac0 block/bio.c:256
 bio_check_pages_dirty+0xbe7/0xc50 block/bio.c:1718
 blkdev_bio_end_io+0x6dc/0x730 fs/block_dev.c:330
 bio_endio+0xa5e/0xbe0 block/bio.c:1845
 req_bio_endio block/blk-core.c:239 [inline]
 blk_update_request+0xcbc/0x1fa0 block/blk-core.c:1424
 blk_mq_end_request+0x9e/0x120 block/blk-mq.c:557
 end_cmd+0x114/0x3e0 drivers/block/null_blk_main.c:622
 null_complete_rq+0x3e/0x50 drivers/block/null_blk_main.c:649
 blk_done_softirq+0x360/0x4e0 block/blk-softirq.c:37
 __do_softirq+0x4a1/0x83a kernel/softirq.c:293
 run_ksoftirqd+0x25/0x40 kernel/softirq.c:607
 smpboot_thread_fn+0x4a3/0x990 kernel/smpboot.c:165
 kthread+0x4b5/0x4f0 kernel/kthread.c:256
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355
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