===================================================== BUG: KMSAN: uninit-value in kmsan_handle_dma_page mm/kmsan/kmsan_hooks.c:328 [inline] BUG: KMSAN: uninit-value in kmsan_handle_dma+0x9f/0xb0 mm/kmsan/kmsan_hooks.c:357 CPU: 1 PID: 9006 Comm: syz-executor.1 Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1df/0x240 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x358/0x3d0 mm/kmsan/kmsan.c:457 kmsan_handle_dma_page mm/kmsan/kmsan_hooks.c:328 [inline] kmsan_handle_dma+0x9f/0xb0 mm/kmsan/kmsan_hooks.c:357 vring_map_one_sg drivers/virtio/virtio_ring.c:336 [inline] virtqueue_add_split drivers/virtio/virtio_ring.c:491 [inline] virtqueue_add+0x46db/0x70f0 drivers/virtio/virtio_ring.c:1714 virtqueue_add_sgs+0x319/0x330 drivers/virtio/virtio_ring.c:1748 __virtscsi_add_cmd drivers/scsi/virtio_scsi.c:447 [inline] virtscsi_add_cmd+0x888/0xb20 drivers/scsi/virtio_scsi.c:481 virtscsi_queuecommand+0xe72/0x1080 drivers/scsi/virtio_scsi.c:578 scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1538 [inline] scsi_queue_rq+0x3eb7/0x4b00 drivers/scsi/scsi_lib.c:1668 blk_mq_dispatch_rq_list+0x931/0x3430 block/blk-mq.c:1277 blk_mq_do_dispatch_sched+0x609/0x880 block/blk-mq-sched.c:134 __blk_mq_sched_dispatch_requests+0x60e/0x8f0 block/blk-mq-sched.c:245 blk_mq_sched_dispatch_requests+0x15d/0x2d0 block/blk-mq-sched.c:276 __blk_mq_run_hw_queue+0x171/0x3a0 block/blk-mq.c:1418 __blk_mq_delay_run_hw_queue+0x15d/0x6a0 block/blk-mq.c:1495 blk_mq_run_hw_queue+0x4ac/0x670 block/blk-mq.c:1548 blk_mq_sched_insert_requests+0x496/0x640 block/blk-mq-sched.c:530 blk_mq_flush_plug_list+0xb21/0xca0 block/blk-mq.c:1817 blk_flush_plug_list+0x72f/0x7b0 block/blk-core.c:1859 blk_finish_plug+0xa0/0xd0 block/blk-core.c:1876 ext4_writepages+0x59d0/0x64c0 fs/ext4/inode.c:2833 do_writepages+0x143/0x400 mm/page-writeback.c:2354 __filemap_fdatawrite_range+0x53b/0x5b0 mm/filemap.c:421 __filemap_fdatawrite mm/filemap.c:429 [inline] filemap_flush+0x66/0x70 mm/filemap.c:456 ext4_alloc_da_blocks+0x22d/0x290 fs/ext4/inode.c:3146 ext4_release_file+0xa0/0x3e0 fs/ext4/file.c:142 __fput+0x4ae/0xb80 fs/file_table.c:281 ____fput+0x37/0x40 fs/file_table.c:314 task_work_run+0x1ee/0x2d0 kernel/task_work.c:135 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:240 [inline] __prepare_exit_to_usermode+0x422/0x4d0 arch/x86/entry/common.c:270 __syscall_return_slowpath+0x89/0x5b0 arch/x86/entry/common.c:353 do_syscall_32_irqs_on arch/x86/entry/common.c:433 [inline] __do_fast_syscall_32+0x303/0x400 arch/x86/entry/common.c:477 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7faf549 Code: Bad RIP value. RSP: 002b:00000000ff8ca1dc EFLAGS: 00000296 ORIG_RAX: 0000000000000006 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000 RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116 memcpy_from_page lib/iov_iter.c:468 [inline] iov_iter_copy_from_user_atomic+0x11b1/0x1780 lib/iov_iter.c:1003 generic_perform_write+0x499/0x9a0 mm/filemap.c:3326 ext4_buffered_write_iter+0x795/0xac0 fs/ext4/file.c:270 ext4_file_write_iter+0x1034/0x2dd0 fs/ext4/file.c:498 do_iter_readv_writev+0x94a/0xb10 include/linux/fs.h:1902 do_iter_write+0x303/0xdc0 fs/read_write.c:1018 vfs_iter_write+0x118/0x180 fs/read_write.c:1059 iter_file_splice_write+0xb5f/0x1800 fs/splice.c:750 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x1fd/0x580 fs/splice.c:1016 splice_direct_to_actor+0x6b2/0xf50 fs/splice.c:971 do_splice_direct+0x342/0x580 fs/splice.c:1059 do_sendfile+0x101b/0x1d40 fs/read_write.c:1540 __do_compat_sys_sendfile fs/read_write.c:1616 [inline] __se_compat_sys_sendfile+0x1cb/0x3c0 fs/read_write.c:1605 __ia32_compat_sys_sendfile+0x56/0x70 fs/read_write.c:1605 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline] __do_fast_syscall_32+0x2aa/0x400 arch/x86/entry/common.c:477 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Uninit was created at: kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:144 kmsan_internal_alloc_meta_for_pages mm/kmsan/kmsan_shadow.c:269 [inline] kmsan_alloc_page+0xb9/0x180 mm/kmsan/kmsan_shadow.c:293 __alloc_pages_nodemask+0x56a2/0x5dc0 mm/page_alloc.c:4889 alloc_pages_current+0x672/0x990 mm/mempolicy.c:2292 alloc_pages include/linux/gfp.h:545 [inline] push_pipe+0x605/0xb70 lib/iov_iter.c:537 __pipe_get_pages lib/iov_iter.c:1278 [inline] pipe_get_pages_alloc lib/iov_iter.c:1385 [inline] iov_iter_get_pages_alloc+0x18a9/0x21c0 lib/iov_iter.c:1403 default_file_splice_read fs/splice.c:385 [inline] do_splice_to+0x4fc/0x14f0 fs/splice.c:871 splice_direct_to_actor+0x45c/0xf50 fs/splice.c:950 do_splice_direct+0x342/0x580 fs/splice.c:1059 do_sendfile+0x101b/0x1d40 fs/read_write.c:1540 __do_compat_sys_sendfile fs/read_write.c:1616 [inline] __se_compat_sys_sendfile+0x1cb/0x3c0 fs/read_write.c:1605 __ia32_compat_sys_sendfile+0x56/0x70 fs/read_write.c:1605 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline] __do_fast_syscall_32+0x2aa/0x400 arch/x86/entry/common.c:477 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Bytes 0-4095 of 4096 are uninitialized Memory access of size 4096 starts at ffffa34058834000 =====================================================