=====================================================
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+0x21c8/0x6540 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+0x21c8/0x6540 drivers/virtio/virtio_ring.c:2210
 virtqueue_add_sgs+0x186/0x1b0 drivers/virtio/virtio_ring.c:2244
 __virtscsi_add_cmd drivers/scsi/virtio_scsi.c:471 [inline]
 virtscsi_add_cmd+0x838/0xad0 drivers/scsi/virtio_scsi.c:505
 virtscsi_queuecommand+0x898/0xa60 drivers/scsi/virtio_scsi.c:602
 scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1518 [inline]
 scsi_queue_rq+0x4cd0/0x5a80 drivers/scsi/scsi_lib.c:1760
 blk_mq_dispatch_rq_list+0x148e/0x3ae0 block/blk-mq.c:2058
 __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+0x11b7/0x26e0 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x12f/0x270 block/blk-mq-sched.c:331
 blk_mq_run_work_fn+0xd0/0x280 block/blk-mq.c:2443
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa81/0x1bd0 kernel/workqueue.c:3335
 worker_thread+0xea5/0x1560 kernel/workqueue.c:3416
 kthread+0x3e2/0x540 kernel/kthread.c:388
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

Uninit was stored to memory at:
 memcpy_from_iter lib/iov_iter.c:73 [inline]
 iterate_bvec include/linux/iov_iter.h:122 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:249 [inline]
 iterate_and_advance include/linux/iov_iter.h:271 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 copy_page_from_iter_atomic+0x12b7/0x2b60 lib/iov_iter.c:481
 generic_perform_write+0x4c1/0xc60 mm/filemap.c:3982
 ext4_buffered_write_iter+0x564/0xaa0 fs/ext4/file.c:299
 ext4_file_write_iter+0x208/0x3450
 __kernel_write_iter+0x68b/0xc40 fs/read_write.c:523
 dump_emit_page fs/coredump.c:890 [inline]
 dump_user_range+0x8dc/0xee0 fs/coredump.c:951
 elf_core_dump+0x520f/0x59c0 fs/binfmt_elf.c:2077
 do_coredump+0x32d5/0x4920 fs/coredump.c:764
 get_signal+0x267e/0x2d00 kernel/signal.c:2896
 arch_do_signal_or_restart+0x53/0xcb0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0xa6/0x160 kernel/entry/common.c:225
 irqentry_exit+0x16/0x60 kernel/entry/common.c:328
 exc_page_fault+0x523/0x730 arch/x86/mm/fault.c:1566
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264
 alloc_pages+0x1bf/0x1e0 mm/mempolicy.c:2335
 dump_user_range+0x4a/0xee0 fs/coredump.c:935
 elf_core_dump+0x520f/0x59c0 fs/binfmt_elf.c:2077
 do_coredump+0x32d5/0x4920 fs/coredump.c:764
 get_signal+0x267e/0x2d00 kernel/signal.c:2896
 arch_do_signal_or_restart+0x53/0xcb0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0xa6/0x160 kernel/entry/common.c:225
 irqentry_exit+0x16/0x60 kernel/entry/common.c:328
 exc_page_fault+0x523/0x730 arch/x86/mm/fault.c:1566
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623

Bytes 0-4095 of 4096 are uninitialized
Memory access of size 4096 starts at ffff88812f687000

CPU: 0 PID: 98 Comm: kworker/0:1H Not tainted 6.8.0-syzkaller-11136-g66a27abac311 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: kblockd blk_mq_run_work_fn
=====================================================