Commit 9088616f authored Mar 16, 2015 by Colin Ian King Committed by Chris Metcalf Apr 17, 2015

arch: tile: fix null pointer dereference on pt_regs pointer



Cppcheck reports the following issue:
[arch/tile/kernel/stack.c:116]: (error) Possible null
  pointer dereference: p

In this case, on reporting on an odd fault, p is set to NULL
and immediately afterwords p is dereferenced iff
!kbt->profile is false.  Rather than doing this check just
return NULL rather than falling through to the potential
null pointer dereference (since the original intentional
outcome would be to return NULL anyhow) for this odd fault
case.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com> [tweaked lightly]

parent 5a3b4e80

arch/tile/kernel/stack.c

+8 −7

Original line number	Diff line number	Diff line
		@@ -108,14 +108,15 @@ static struct pt_regs valid_fault_handler(struct KBacktraceIterator kbt)
		p->sp < PAGE_OFFSET && p->sp != 0) {
		if (kbt->verbose)
		pr_err(" <%s while in user mode>\n", fault);
		} else if (kbt->verbose) {
		} else {
		if (kbt->verbose)
		pr_err(" (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
		p->pc, p->sp, p->ex1);
		p = NULL;
		return NULL;
		}
		if (!kbt->profile \|\| ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) == 0)
		return p;
		if (kbt->profile && ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) != 0)
		return NULL;
		return p;
		}

		/* Is the pc pointing to a sigreturn trampoline? */

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