=====================================================
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+0x21c8/0x6530 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+0x21c8/0x6530 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: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+0x4cdd/0x5a80 drivers/scsi/scsi_lib.c:1760
 blk_mq_dispatch_rq_list+0x144f/0x3a40 block/blk-mq.c:2070
 __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+0x11a8/0x26d0 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x12f/0x260 block/blk-mq-sched.c:331
 blk_mq_run_work_fn+0xd0/0x280 block/blk-mq.c:2455
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x1132/0x1f40 kernel/workqueue.c:2706
 worker_thread+0xea4/0x1560 kernel/workqueue.c:2787
 kthread+0x3ed/0x550 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:243

Uninit was created at:
 __alloc_pages+0x9a6/0xe00 mm/page_alloc.c:4590
 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:975
 __filemap_get_folio+0x9aa/0x13f0 mm/filemap.c:1919
 ext4_da_write_begin+0x7f8/0xec0 fs/ext4/inode.c:2885
 generic_perform_write+0x3f5/0xc40 mm/filemap.c:3930
 ext4_buffered_write_iter+0x564/0xaa0 fs/ext4/file.c:299
 ext4_file_write_iter+0x20f/0x3470
 __kernel_write_iter+0x686/0xc30 fs/read_write.c:523
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x593/0xcd0 fs/coredump.c:915
 elf_core_dump+0x5294/0x5a40 fs/binfmt_elf.c:2077
 do_coredump+0x32c9/0x4920 fs/coredump.c:764
 get_signal+0x21fa/0x2d80 kernel/signal.c:2879
 arch_do_signal_or_restart+0x53/0xca0 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+0xa1/0x150 kernel/entry/common.c:225
 irqentry_exit+0x16/0x50 kernel/entry/common.c:328
 exc_page_fault+0x534/0x720 arch/x86/mm/fault.c:1557
 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 ffff88812f1a8000

CPU: 0 PID: 52 Comm: kworker/0:1H Not tainted 6.8.0-rc6-syzkaller-00238-g5ad3cb0ed525 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: kblockd blk_mq_run_work_fn
=====================================================