On Thu, 2013-12-05 at 13:45 +0100, Jean Pihet wrote: > On 5 December 2013 09:34, Konstantin Khlebnikov > <k.khlebni...@samsung.com> wrote: > > This patch fixes corner case when (fp + 4) overflows unsigned long, > > for example: fp = 0xFFFFFFFF -> fp + 4 == 3. > > > > Signed-off-by: Konstantin Khlebnikov <k.khlebni...@samsung.com> > > --- > > arch/arm/kernel/stacktrace.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c > > index 00f79e5..af4e8c8 100644 > > --- a/arch/arm/kernel/stacktrace.c > > +++ b/arch/arm/kernel/stacktrace.c > > @@ -31,7 +31,7 @@ int notrace unwind_frame(struct stackframe *frame) > > high = ALIGN(low, THREAD_SIZE); > > > > /* check current frame pointer is within bounds */ > > - if (fp < (low + 12) || fp + 4 >= high) > > + if (fp < low + 12 || fp > high - 4) > Shouldn't that use the '>=' comparison?
nope, fp == high-4 is fine: -------------------+ ... -5 -4 -3 -2 -1 | -0 -------------------+ ^ ^ +---- fp +----- high stack frame contains four 'unsigned long' values: {fp, sp, lr, pc}. 'fp' points to 'pc', so totally there are 16 bytes: fp-12..fp+3 > > Jean > > return -EINVAL; > > > > /* restore the registers from the stack frame */ > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majord...@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/