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BUG: KMSAN: uninit-value in ident_p4d_init arch/x86/mm/ident_map.c:74 [inline]
BUG: KMSAN: uninit-value in kernel_ident_mapping_init+0x65a/0x8d0 arch/x86/mm/ident_map.c:111
CPU: 0 PID: 4506 Comm: syz-executor502 Not tainted 4.16.0+ #87
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
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 ident_p4d_init arch/x86/mm/ident_map.c:74 [inline]
 kernel_ident_mapping_init+0x65a/0x8d0 arch/x86/mm/ident_map.c:111
 init_pgtable arch/x86/kernel/machine_kexec_64.c:135 [inline]
 machine_kexec_prepare+0x27f/0x1090 arch/x86/kernel/machine_kexec_64.c:253
 do_kexec_load kernel/kexec.c:143 [inline]
 SYSC_kexec_load+0xb8a/0xe80 kernel/kexec.c:233
 SyS_kexec_load+0x66/0x90 kernel/kexec.c:195
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x445449
RSP: 002b:00007ffb9038ddb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f6
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445449
RDX: 0000000020003600 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00000000006dac20 R08: 00007ffb9038e700 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc9dfb09cf R14: 00007ffb9038e9c0 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_current+0x6b5/0x970 mm/mempolicy.c:2055
 alloc_pages include/linux/gfp.h:494 [inline]
 kimage_alloc_pages kernel/kexec_core.c:304 [inline]
 kimage_alloc_normal_control_pages kernel/kexec_core.c:378 [inline]
 kimage_alloc_control_pages+0x177/0x1490 kernel/kexec_core.c:485
 kimage_alloc_init kernel/kexec.c:83 [inline]
 do_kexec_load kernel/kexec.c:136 [inline]
 SYSC_kexec_load+0x85b/0xe80 kernel/kexec.c:233
 SyS_kexec_load+0x66/0x90 kernel/kexec.c:195
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
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