netlink: 8 bytes leftover after parsing attributes in process `syz-executor4'. ================================================================== BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184 [inline] BUG: KMSAN: uninit-value in vcs_read+0x18ba/0x1cc0 drivers/tty/vt/vc_screen.c:352 CPU: 1 PID: 12437 Comm: syz-executor5 Not tainted 4.17.0-rc5+ #103 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+0x185/0x1d0 lib/dump_stack.c:113 kmsan_report+0x149/0x260 mm/kmsan/kmsan.c:1084 kmsan_internal_check_memory+0x179/0x1e0 mm/kmsan/kmsan.c:1196 kmsan_copy_to_user+0x75/0x160 mm/kmsan/kmsan.c:1219 copy_to_user include/linux/uaccess.h:184 [inline] vcs_read+0x18ba/0x1cc0 drivers/tty/vt/vc_screen.c:352 __vfs_read+0x1a5/0x9b0 fs/read_write.c:416 vfs_read+0x36c/0x6b0 fs/read_write.c:452 ksys_read fs/read_write.c:578 [inline] __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x1bf/0x3e0 fs/read_write.c:586 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x455a09 RSP: 002b:00007f24020b7c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f24020b86d4 RCX: 0000000000455a09 RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000567 R14: 00000000006fd248 R15: 0000000000000000 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline] kmsan_save_stack mm/kmsan/kmsan.c:294 [inline] kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:529 vcs_read+0xd01/0x1cc0 drivers/tty/vt/vc_screen.c:274 __vfs_read+0x1a5/0x9b0 fs/read_write.c:416 vfs_read+0x36c/0x6b0 fs/read_write.c:452 ksys_read fs/read_write.c:578 [inline] __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x1bf/0x3e0 fs/read_write.c:586 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315 __kmalloc+0x141/0x350 mm/slub.c:3818 kmalloc include/linux/slab.h:517 [inline] vc_allocate+0x438/0x800 drivers/tty/vt/vt.c:787 con_install+0x8c/0x640 drivers/tty/vt/vt.c:2880 tty_driver_install_tty drivers/tty/tty_io.c:1224 [inline] tty_init_dev+0x1b0/0x1020 drivers/tty/tty_io.c:1324 tty_open_by_driver drivers/tty/tty_io.c:1959 [inline] tty_open+0x15e7/0x2ea0 drivers/tty/tty_io.c:2007 chrdev_open+0xc20/0xd90 fs/char_dev.c:417 do_dentry_open+0xcf8/0x15f0 fs/open.c:784 vfs_open+0x1b7/0x2e0 fs/open.c:906 do_last fs/namei.c:3365 [inline] path_openat+0x4724/0x6470 fs/namei.c:3501 do_filp_open+0x261/0x640 fs/namei.c:3535 do_sys_open+0x624/0x960 fs/open.c:1093 __do_sys_open fs/open.c:1111 [inline] __se_sys_open fs/open.c:1106 [inline] __x64_sys_open+0xf2/0x130 fs/open.c:1106 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Bytes 0-7 of 8 are uninitialized Memory access starts at ffff880196f1d000 ==================================================================