================================================================== BUG: KMSAN: uninit-value in copyout lib/iov_iter.c:140 [inline] BUG: KMSAN: uninit-value in copy_page_to_iter_iovec lib/iov_iter.c:212 [inline] BUG: KMSAN: uninit-value in copy_page_to_iter+0x754/0x1b70 lib/iov_iter.c:716 CPU: 1 PID: 5776 Comm: syz-executor3 Not tainted 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 kmsan_internal_check_memory+0x164/0x1d0 mm/kmsan/kmsan.c:1176 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199 copyout lib/iov_iter.c:140 [inline] copy_page_to_iter_iovec lib/iov_iter.c:212 [inline] copy_page_to_iter+0x754/0x1b70 lib/iov_iter.c:716 shmem_file_read_iter+0x99f/0x1180 mm/shmem.c:2507 do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776 do_iter_read+0x303/0xd70 fs/read_write.c:895 vfs_readv fs/read_write.c:959 [inline] do_preadv+0x3a1/0x580 fs/read_write.c:1043 SYSC_preadv+0xc6/0xe0 fs/read_write.c:1093 SyS_preadv+0x77/0xa0 fs/read_write.c:1088 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x455259 RSP: 002b:00007fd251a5ac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007fd251a5b6d4 RCX: 0000000000455259 RDX: 0000000000000007 RSI: 0000000020000400 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000046f R14: 00000000006f9b08 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_alloc_meta_for_pages+0x161/0x3a0 mm/kmsan/kmsan.c:814 kmsan_alloc_page+0x82/0xe0 mm/kmsan/kmsan.c:868 __alloc_pages_nodemask+0xf5b/0x5dc0 mm/page_alloc.c:4283 alloc_pages_vma+0xcc8/0x1800 mm/mempolicy.c:2019 shmem_alloc_page mm/shmem.c:1471 [inline] shmem_alloc_and_acct_page+0x6d5/0x1000 mm/shmem.c:1496 shmem_getpage_gfp+0x35db/0x5770 mm/shmem.c:1771 shmem_getpage mm/shmem.c:131 [inline] shmem_fallocate+0xde2/0x1610 mm/shmem.c:2939 vfs_fallocate+0x9dc/0xde0 fs/open.c:319 SYSC_fallocate+0x119/0x1d0 fs/open.c:342 SyS_fallocate+0x64/0x90 fs/open.c:336 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Bytes 0-76 of 77 are uninitialized ==================================================================