f75b1b1bed
UML needs it's own probe_kernel_read() to handle kernel mode faults correctly. The implementation uses mincore() on the host side to detect whether a page is owned by the UML kernel process. This fixes also a possible crash when sysrq-t is used. Starting with 3.10 sysrq-t calls probe_kernel_read() to read details from the kernel workers. As kernel worker are completely async pointers may turn NULL while reading them. Cc: <stian@nixia.no> Cc: <tj@kernel.org> Cc: <stable@vger.kernel.org> # 3.10.x Signed-off-by: Richard Weinberger <richard@nod.at>
24 lines
638 B
C
24 lines
638 B
C
/*
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* Copyright (C) 2013 Richard Weinberger <richrd@nod.at>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#include <os.h>
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long probe_kernel_read(void *dst, const void *src, size_t size)
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{
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void *psrc = (void *)rounddown((unsigned long)src, PAGE_SIZE);
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if ((unsigned long)src < PAGE_SIZE || size <= 0)
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return -EFAULT;
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if (os_mincore(psrc, size + src - psrc) <= 0)
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return -EFAULT;
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return __probe_kernel_read(dst, src, size);
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}
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