===================================================== BUG: KMSAN: uninit-value in kmsan_handle_dma_page mm/kmsan/kmsan_hooks.c:348 [inline] BUG: KMSAN: uninit-value in kmsan_handle_dma+0x9f/0xb0 mm/kmsan/kmsan_hooks.c:375 CPU: 1 PID: 8881 Comm: syz-executor327 Not tainted 5.6.0-rc7-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+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423 kmsan_handle_dma_page mm/kmsan/kmsan_hooks.c:348 [inline] kmsan_handle_dma+0x9f/0xb0 mm/kmsan/kmsan_hooks.c:375 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+0xe7e/0x1090 drivers/scsi/virtio_scsi.c:578 scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1554 [inline] scsi_queue_rq+0x41c5/0x4d20 drivers/scsi/scsi_lib.c:1689 blk_mq_dispatch_rq_list+0xf81/0x2850 block/blk-mq.c:1246 blk_mq_do_dispatch_sched block/blk-mq-sched.c:115 [inline] blk_mq_sched_dispatch_requests+0xbe0/0x1840 block/blk-mq-sched.c:216 __blk_mq_run_hw_queue+0x171/0x3a0 block/blk-mq.c:1382 __blk_mq_delay_run_hw_queue+0x15d/0x6a0 block/blk-mq.c:1459 blk_mq_run_hw_queue+0x4ac/0x670 block/blk-mq.c:1512 blk_mq_sched_insert_requests+0x496/0x640 block/blk-mq-sched.c:474 blk_mq_flush_plug_list+0xb31/0xca0 block/blk-mq.c:1762 blk_flush_plug_list+0x70f/0x790 block/blk-core.c:1766 blk_finish_plug+0xa0/0xd0 block/blk-core.c:1783 ext4_writepages+0x57e1/0x62a0 fs/ext4/inode.c:2833 do_writepages+0x143/0x400 mm/page-writeback.c:2344 __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+0x4c7/0xb90 fs/file_table.c:280 ____fput+0x37/0x40 fs/file_table.c:313 task_work_run+0x214/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x3c8/0x520 arch/x86/entry/common.c:195 syscall_return_slowpath+0x95/0x5f0 arch/x86/entry/common.c:278 do_syscall_32_irqs_on arch/x86/entry/common.c:354 [inline] do_fast_syscall_32+0x422/0x6e0 arch/x86/entry/common.c:410 entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f86d99 Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000ffd8507c EFLAGS: 00000296 ORIG_RAX: 0000000000000006 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000004 RSI: 00000000080fd00c RDI: 0000000000000006 RBP: 00000000ffd850c4 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:470 [inline] iov_iter_copy_from_user_atomic+0xf5b/0x1500 lib/iov_iter.c:1005 generic_perform_write+0x499/0x9a0 mm/filemap.c:3295 ext4_buffered_write_iter+0x795/0xac0 fs/ext4/file.c:270 ext4_file_write_iter+0x1330/0x2c70 fs/ext4/file.c:491 do_iter_readv_writev+0xa23/0xc70 include/linux/fs.h:1896 do_iter_write+0x304/0xdc0 fs/read_write.c:998 vfs_iter_write+0x118/0x180 fs/read_write.c:1039 iter_file_splice_write+0xb1b/0x17b0 fs/splice.c:760 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x19e/0x200 fs/splice.c:1037 splice_direct_to_actor+0x8a9/0x11e0 fs/splice.c:992 do_splice_direct+0x342/0x580 fs/splice.c:1080 do_sendfile+0xff5/0x1d10 fs/read_write.c:1520 __do_compat_sys_sendfile fs/read_write.c:1602 [inline] __se_compat_sys_sendfile+0x301/0x3c0 fs/read_write.c:1585 __ia32_compat_sys_sendfile+0x11a/0x160 fs/read_write.c:1585 do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline] do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410 entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139 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 kmsan_copy_to_user+0x50/0x90 mm/kmsan/kmsan_hooks.c:262 _copy_to_user+0x15a/0x1f0 lib/usercopy.c:33 copy_to_user include/linux/uaccess.h:174 [inline] proc_put_long kernel/sysctl.c:2260 [inline] __do_proc_dointvec+0xed3/0x1a70 kernel/sysctl.c:2385 do_proc_dointvec kernel/sysctl.c:2412 [inline] proc_dointvec+0x139/0x160 kernel/sysctl.c:2572 proc_sys_call_handler+0xa92/0xd00 fs/proc/proc_sysctl.c:616 proc_sys_read+0xc6/0xe0 fs/proc/proc_sysctl.c:630 do_loop_readv_writev fs/read_write.c:714 [inline] do_iter_read+0x8df/0xe10 fs/read_write.c:935 vfs_readv+0x1ee/0x280 fs/read_write.c:1053 kernel_readv fs/splice.c:365 [inline] default_file_splice_read+0xb1d/0x11d0 fs/splice.c:422 do_splice_to fs/splice.c:892 [inline] splice_direct_to_actor+0x5d8/0x11e0 fs/splice.c:971 do_splice_direct+0x342/0x580 fs/splice.c:1080 do_sendfile+0xff5/0x1d10 fs/read_write.c:1520 __do_compat_sys_sendfile fs/read_write.c:1602 [inline] __se_compat_sys_sendfile+0x301/0x3c0 fs/read_write.c:1585 __ia32_compat_sys_sendfile+0x11a/0x160 fs/read_write.c:1585 do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline] do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410 entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139 Local variable ----tmp.i@__do_proc_dointvec created at: proc_put_long kernel/sysctl.c:2256 [inline] __do_proc_dointvec+0xd1b/0x1a70 kernel/sysctl.c:2385 proc_put_long kernel/sysctl.c:2256 [inline] __do_proc_dointvec+0xd1b/0x1a70 kernel/sysctl.c:2385 Byte 1 of 4096 is uninitialized Memory access of size 4096 starts at ffff9e1ef3e37000 =====================================================