=====================================================
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+0x1e86/0x65c0 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+0x1e86/0x65c0 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:1609 [inline]
 scsi_queue_rq+0x4cc7/0x5a80 drivers/scsi/scsi_lib.c:1851
 blk_mq_dispatch_rq_list+0x79b/0x3440 block/blk-mq.c:2037
 __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_hw_queue+0x6e4/0xbc0 block/blk-mq.c:2250
 blk_mq_flush_plug_list+0x1683/0x2b20 block/blk-mq.c:2799
 blk_add_rq_to_plug+0x2c6/0x970 block/blk-mq.c:1297
 blk_mq_submit_bio+0x26e8/0x3390 block/blk-mq.c:3013
 __submit_bio+0x3b9/0xb60 block/blk-core.c:620
 __submit_bio_noacct_mq block/blk-core.c:704 [inline]
 submit_bio_noacct_nocheck+0x148c/0x1800 block/blk-core.c:734
 submit_bio_noacct+0x1bd8/0x27f0 block/blk-core.c:844
 submit_bio+0x58a/0x5b0 block/blk-core.c:886
 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+0x1e76/0x2e40 fs/ext4/page-io.c:563
 mpage_submit_folio+0x351/0x4a0 fs/ext4/inode.c:1869
 mpage_map_and_submit_buffers fs/ext4/inode.c:2115 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2254 [inline]
 ext4_do_writepages+0x3733/0x62e0 fs/ext4/inode.c:2679
 ext4_writepages+0x312/0x830 fs/ext4/inode.c:2768
 do_writepages+0x427/0xc30 mm/page-writeback.c:2613
 filemap_fdatawrite_wbc+0x1d8/0x270 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 __filemap_fdatawrite mm/filemap.c:436 [inline]
 filemap_flush+0xa3/0xd0 mm/filemap.c:463
 ext4_alloc_da_blocks+0xa3/0x270 fs/ext4/inode.c:3072
 ext4_release_file+0xcd/0x400 fs/ext4/file.c:169
 __fput+0x6a1/0x10c0 fs/file_table.c:422
 ____fput+0x1e/0x30 fs/file_table.c:450
 task_work_run+0x268/0x310 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x160 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

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+0x12b7/0x2ae0 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+0x64d/0xc80 fs/read_write.c:523
 dump_emit_page fs/coredump.c:895 [inline]
 dump_user_range+0x8dc/0xee0 fs/coredump.c:956
 elf_core_dump+0x57c7/0x5ae0 fs/binfmt_elf.c:2083
 do_coredump+0x32d5/0x4920 fs/coredump.c:769
 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:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x5d/0x160 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

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:940
 elf_core_dump+0x57c7/0x5ae0 fs/binfmt_elf.c:2083
 do_coredump+0x32d5/0x4920 fs/coredump.c:769
 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:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x5d/0x160 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Bytes 0-4095 of 4096 are uninitialized
Memory access of size 4096 starts at ffff8881343f5000

CPU: 1 PID: 25575 Comm: syz-executor.2 Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
=====================================================