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BUG: KMSAN: uninit-value in vring_map_one_sg drivers/virtio/virtio_ring.c:368 [inline]
BUG: KMSAN: uninit-value in virtqueue_add_split drivers/virtio/virtio_ring.c:591 [inline]
BUG: KMSAN: uninit-value in virtqueue_add+0x20e2/0x60f0 drivers/virtio/virtio_ring.c:2133
 vring_map_one_sg drivers/virtio/virtio_ring.c:368 [inline]
 virtqueue_add_split drivers/virtio/virtio_ring.c:591 [inline]
 virtqueue_add+0x20e2/0x60f0 drivers/virtio/virtio_ring.c:2133
 virtqueue_add_sgs+0x186/0x1a0 drivers/virtio/virtio_ring.c:2167
 __virtscsi_add_cmd drivers/scsi/virtio_scsi.c:469 [inline]
 virtscsi_add_cmd+0x838/0xad0 drivers/scsi/virtio_scsi.c:503
 virtscsi_queuecommand+0x895/0xa60 drivers/scsi/virtio_scsi.c:600
 scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1519 [inline]
 scsi_queue_rq+0x4931/0x5680 drivers/scsi/scsi_lib.c:1761
 blk_mq_dispatch_rq_list+0x1184/0x39c0 block/blk-mq.c:2035
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
 __blk_mq_sched_dispatch_requests+0x1234/0x2670 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x15d/0x2c0 block/blk-mq-sched.c:333
 blk_mq_run_hw_queue+0x6b3/0xb70 block/blk-mq.c:2249
 blk_mq_flush_plug_list+0x1b80/0x24c0 block/blk-mq.c:2783
 blk_add_rq_to_plug+0x2c6/0x960 block/blk-mq.c:1266
 blk_mq_submit_bio+0x2774/0x3320 block/blk-mq.c:2979
 __submit_bio+0x3b7/0xb30 block/blk-core.c:594
 __submit_bio_noacct_mq block/blk-core.c:673 [inline]
 submit_bio_noacct_nocheck+0xf6b/0x1240 block/blk-core.c:702
 submit_bio_noacct+0x201c/0x2380 block/blk-core.c:801
 submit_bio+0x171/0x1c0 block/blk-core.c:834
 ext4_io_submit fs/ext4/page-io.c:378 [inline]
 io_submit_add_bh fs/ext4/page-io.c:419 [inline]
 ext4_bio_write_folio+0x1c60/0x2ad0 fs/ext4/page-io.c:563
 mpage_submit_folio fs/ext4/inode.c:1889 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2135 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2275 [inline]
 ext4_do_writepages+0x3c5d/0x69b0 fs/ext4/inode.c:2703
 ext4_writepages+0x30c/0x810 fs/ext4/inode.c:2792
 do_writepages+0x428/0x870 mm/page-writeback.c:2551
 __writeback_single_inode+0x10d/0x12b0 fs/fs-writeback.c:1603
 writeback_sb_inodes+0xb76/0x1c00 fs/fs-writeback.c:1894
 __writeback_inodes_wb+0x14c/0x440 fs/fs-writeback.c:1965
 wb_writeback+0x4cc/0xdf0 fs/fs-writeback.c:2070
 wb_check_old_data_flush fs/fs-writeback.c:2170 [inline]
 wb_do_writeback fs/fs-writeback.c:2223 [inline]
 wb_workfn+0x104e/0x1710 fs/fs-writeback.c:2251
 process_one_work+0xb0d/0x1410 kernel/workqueue.c:2408
 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2555
 kthread+0x3e8/0x540 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4791
 alloc_pages+0xd01/0x1040
 folio_alloc+0x42/0x120 mm/mempolicy.c:2289
 filemap_alloc_folio+0xa5/0x430 mm/filemap.c:976
 __filemap_get_folio+0x908/0x13a0 mm/filemap.c:1971
 ext4_da_write_begin+0x7f8/0xec0 fs/ext4/inode.c:2909
 generic_perform_write+0x3df/0xbb0 mm/filemap.c:3929
 ext4_buffered_write_iter+0x5ec/0xbe0 fs/ext4/file.c:289
 ext4_file_write_iter+0x2365/0x3400
 __kernel_write_iter+0x323/0x930 fs/read_write.c:517
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x593/0xce0 fs/coredump.c:915
 elf_core_dump+0x59e8/0x5c60 fs/binfmt_elf.c:2142
 do_coredump+0x32c8/0x4910 fs/coredump.c:764
 get_signal+0x2185/0x2bc0 kernel/signal.c:2862
 arch_do_signal_or_restart+0x4f/0x920 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop+0xe8/0x320 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x163/0x220 kernel/entry/common.c:204
 irqentry_exit_to_user_mode+0xd/0x20 kernel/entry/common.c:310
 irqentry_exit+0x16/0x40 kernel/entry/common.c:413
 exc_page_fault+0x5a5/0x740 arch/x86/mm/fault.c:1593
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:570

Bytes 0-4095 of 4096 are uninitialized
Memory access of size 4096 starts at ffff8881500f6000

CPU: 1 PID: 2969 Comm: kworker/u4:11 Not tainted 6.4.0-syzkaller-g257152fe29be #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: writeback wb_workfn (flush-8:0)
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