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BUG: KMSAN: uninit-value in do_error_trap+0x39b/0x600 arch/x86/kernel/traps.c:297
CPU: 0 PID: 7040 Comm: syz-executor1 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
 do_error_trap+0x39b/0x600 arch/x86/kernel/traps.c:297
 do_invalid_op+0x46/0x50 arch/x86/kernel/traps.c:316
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RIP: 0010:kmsan_copy_to_user+0x141/0x160 mm/kmsan/kmsan.c:1213
RSP: 0018:ffff88014876fba0 EFLAGS: 00010206
RAX: ffff88014b841d80 RBX: ffff88014876fc10 RCX: 0000000000000024
RDX: 00007ffffffff000 RSI: ffff88014876fc10 RDI: fffffffffffffffc
RBP: ffff88014876fbe8 R08: 00000000000007e2 R09: 0000000000000000
R10: ffffffff7fffffff R11: 0000000000100000 R12: 0000000000000024
R13: fffffffffffffffc R14: ffff88014b842698 R15: 0000000000000024
 copy_to_user include/linux/uaccess.h:184 [inline]
 rtc_dev_ioctl+0x5f5/0x1310 drivers/rtc/rtc-dev.c:268
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0xaf0/0x2440 fs/ioctl.c:686
 SYSC_ioctl+0x1d2/0x260 fs/ioctl.c:701
 SyS_ioctl+0x54/0x80 fs/ioctl.c:692
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455979
RSP: 002b:00007f618da10c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f618da116d4 RCX: 0000000000455979
RDX: fffffffffffffffc RSI: 0000000080247009 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000034c R14: 00000000006f8fc0 R15: 0000000000000000

Local variable description: ----iter@filemap_map_pages
Variable was created at:
 filemap_map_pages+0x12d/0x1ac0 mm/filemap.c:2617
 do_fault_around mm/memory.c:3609 [inline]
 do_read_fault mm/memory.c:3643 [inline]
 do_fault mm/memory.c:3748 [inline]
 handle_pte_fault mm/memory.c:3979 [inline]
 __handle_mm_fault mm/memory.c:4103 [inline]
 handle_mm_fault+0x44ba/0x7e50 mm/memory.c:4140
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