Revision f2d7b53c0153f2daa8bc8f1ff29b5a1e03a36458 authored by Alexander Potapenko on 02 November 2022, 10:15:00 UTC, committed by Alexander Potapenko on 02 November 2022, 10:55:06 UTC
There is a case in exc_invalid_op handler that is executed outside the
irqentry_enter()/irqentry_exit() region when an UD2 instruction is used
to encode a call to __warn().

In that case the `struct pt_regs` passed to the interrupt handler is
never unpoisoned by KMSAN (this is normally done in irqentry_enter()),
which leads to false positives inside handle_bug().

Use kmsan_unpoison_entry_regs() to explicitly unpoison those registers
before using them.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Signed-off-by: Alexander Potapenko <glider@google.com>
1 parent 4dbc4d5
Raw File
memcat_p.c
// SPDX-License-Identifier: GPL-2.0

#include <linux/slab.h>

/*
 * Merge two NULL-terminated pointer arrays into a newly allocated
 * array, which is also NULL-terminated. Nomenclature is inspired by
 * memset_p() and memcat() found elsewhere in the kernel source tree.
 */
void **__memcat_p(void **a, void **b)
{
	void **p = a, **new;
	int nr;

	/* count the elements in both arrays */
	for (nr = 0, p = a; *p; nr++, p++)
		;
	for (p = b; *p; nr++, p++)
		;
	/* one for the NULL-terminator */
	nr++;

	new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL);
	if (!new)
		return NULL;

	/* nr -> last index; p points to NULL in b[] */
	for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1)
		new[nr] = *p;

	return new;
}
EXPORT_SYMBOL_GPL(__memcat_p);

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