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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: 0 PID: 5236 Comm: syz-executor6 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
 process_vm_rw_pages mm/process_vm_access.c:53 [inline]
 process_vm_rw_single_vec mm/process_vm_access.c:124 [inline]
 process_vm_rw_core+0xf6a/0x1930 mm/process_vm_access.c:220
 process_vm_rw+0x3d5/0x500 mm/process_vm_access.c:288
 SYSC_process_vm_readv+0x126/0x140 mm/process_vm_access.c:302
 SyS_process_vm_readv+0x8a/0xb0 mm/process_vm_access.c:298
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455259
RSP: 002b:00007f24e2981c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 00007f24e29826d4 RCX: 0000000000455259
RDX: 0000000000000001 RSI: 0000000020de4000 RDI: 00000000000000b9
RBP: 000000000072c010 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020d65fb8 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000471 R14: 00000000006f9b38 R15: 0000000000000002

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 include/linux/gfp.h:458 [inline]
 __alloc_pages_node include/linux/gfp.h:471 [inline]
 alloc_pages_vma+0x1565/0x1800 mm/mempolicy.c:2011
 do_huge_pmd_anonymous_page+0xf80/0x2520 mm/huge_memory.c:723
 create_huge_pmd mm/memory.c:3870 [inline]
 __handle_mm_fault mm/memory.c:4074 [inline]
 handle_mm_fault+0x30ba/0x7ba0 mm/memory.c:4140
 __do_page_fault+0xec4/0x1a10 arch/x86/mm/fault.c:1423
 do_page_fault+0xd3/0x260 arch/x86/mm/fault.c:1500
 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1151
 copy_user_generic_unrolled+0x89/0xc0 arch/x86/lib/copy_user_64.S:66
 copy_to_user include/linux/uaccess.h:183 [inline]
 seq_read+0x1c5f/0x2260 fs/seq_file.c:282
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x880/0xd70 fs/read_write.c:897
 vfs_readv fs/read_write.c:959 [inline]
 do_readv+0x295/0x5f0 fs/read_write.c:992
 SYSC_readv+0x9b/0xb0 fs/read_write.c:1079
 SyS_readv+0x56/0x80 fs/read_write.c:1076
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Bytes 0-74 of 75 are uninitialized
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