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BUG: KMSAN: uninit-value in vring_map_one_sg drivers/virtio/virtio_ring.c:380 [inline]
BUG: KMSAN: uninit-value in virtqueue_add_split drivers/virtio/virtio_ring.c:614 [inline]
BUG: KMSAN: uninit-value in virtqueue_add+0x21c6/0x6530 drivers/virtio/virtio_ring.c:2210
 vring_map_one_sg drivers/virtio/virtio_ring.c:380 [inline]
 virtqueue_add_split drivers/virtio/virtio_ring.c:614 [inline]
 virtqueue_add+0x21c6/0x6530 drivers/virtio/virtio_ring.c:2210
 virtqueue_add_sgs+0x186/0x1a0 drivers/virtio/virtio_ring.c:2244
 __virtscsi_add_cmd drivers/scsi/virtio_scsi.c:467 [inline]
 virtscsi_add_cmd+0x838/0xad0 drivers/scsi/virtio_scsi.c:501
 virtscsi_queuecommand+0x896/0xa60 drivers/scsi/virtio_scsi.c:598
 scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1516 [inline]
 scsi_queue_rq+0x4874/0x5790 drivers/scsi/scsi_lib.c:1758
 blk_mq_dispatch_rq_list+0x13f8/0x3600 block/blk-mq.c:2049
 __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+0x10af/0x2500 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x160/0x2d0 block/blk-mq-sched.c:333
 blk_mq_run_hw_queue+0x6e2/0xbb0 block/blk-mq.c:2264
 blk_mq_flush_plug_list+0x143f/0x2a80 block/blk-mq.c:2812
 blk_add_rq_to_plug+0x2c7/0x960 block/blk-mq.c:1294
 blk_mq_submit_bio+0x2005/0x3580 block/blk-mq.c:3008
 __submit_bio+0x3ba/0xb30 block/blk-core.c:607
 __submit_bio_noacct_mq block/blk-core.c:686 [inline]
 submit_bio_noacct_nocheck+0xf6b/0x1240 block/blk-core.c:715
 submit_bio_noacct+0x1d55/0x2840 block/blk-core.c:809
 submit_bio+0x171/0x1c0 block/blk-core.c:842
 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+0x1df7/0x2db0 fs/ext4/page-io.c:563
 mpage_submit_folio fs/ext4/inode.c:1875 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2121 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2260 [inline]
 ext4_do_writepages+0x3b41/0x67e0 fs/ext4/inode.c:2685
 ext4_writepages+0x30c/0x810 fs/ext4/inode.c:2774
 do_writepages+0x426/0x870 mm/page-writeback.c:2553
 __writeback_single_inode+0x10d/0x12b0 fs/fs-writeback.c:1625
 writeback_sb_inodes+0xb73/0x1c00 fs/fs-writeback.c:1916
 __writeback_inodes_wb+0x14c/0x440 fs/fs-writeback.c:1987
 wb_writeback+0x4da/0xdf0 fs/fs-writeback.c:2094
 wb_check_background_flush fs/fs-writeback.c:2164 [inline]
 wb_do_writeback fs/fs-writeback.c:2252 [inline]
 wb_workfn+0x116a/0x1710 fs/fs-writeback.c:2279
 process_one_work kernel/workqueue.c:2627 [inline]
 process_scheduled_works+0x104e/0x1e70 kernel/workqueue.c:2700
 worker_thread+0xf45/0x1490 kernel/workqueue.c:2781
 kthread+0x3ed/0x540 kernel/kthread.c:388
 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4591
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages mm/mempolicy.c:2204 [inline]
 folio_alloc+0x1da/0x380 mm/mempolicy.c:2211
 filemap_alloc_folio+0xa5/0x430 mm/filemap.c:974
 __filemap_get_folio+0xa5a/0x1760 mm/filemap.c:1918
 ext4_da_write_begin+0x7f8/0xec0 fs/ext4/inode.c:2891
 generic_perform_write+0x3f5/0xc40 mm/filemap.c:3918
 ext4_buffered_write_iter+0x564/0xaa0 fs/ext4/file.c:299
 ext4_file_write_iter+0x20f/0x3460
 __kernel_write_iter+0x329/0x930 fs/read_write.c:517
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x593/0xcd0 fs/coredump.c:915
 elf_core_dump+0x59e8/0x5c60 fs/binfmt_elf.c:2077
 do_coredump+0x32c9/0x4920 fs/coredump.c:764
 get_signal+0x2185/0x2d10 kernel/signal.c:2890
 arch_do_signal_or_restart+0x53/0xca0 arch/x86/kernel/signal.c:309
 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/0x30 kernel/entry/common.c:309
 irqentry_exit+0x16/0x40 kernel/entry/common.c:412
 exc_page_fault+0x246/0x6f0 arch/x86/mm/fault.c:1564
 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 ffff88812b931000

CPU: 0 PID: 6253 Comm: kworker/u4:10 Not tainted 6.7.0-rc6-syzkaller-00022-g55cb5f43689d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: writeback wb_workfn (flush-8:0)
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