Messages in this thread | | | Date | Thu, 17 May 2018 14:31:51 +0100 | From | Daniel Thompson <> | Subject | Re: [PATCH] misc: kgdbts: silence array underflow warning |
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On Thu, May 17, 2018 at 03:22:29PM +0300, Dan Carpenter wrote: > Smatch distrusts simple_strtol(). I don't know the code well enough > to say if the distrust is justified here, but it seems harmless to > silence the warning.
What warning does this fix? I'd prefer to have it in the description.
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c > index 6193270e7b3d..e0508acaedaa 100644 > --- a/drivers/misc/kgdbts.c > +++ b/drivers/misc/kgdbts.c > @@ -400,13 +400,15 @@ static void skip_back_repeat_test(char *arg) > int go_back = simple_strtol(arg, NULL, 10);
If go_back is out of range then this is a serious error in the test plans found in the module. Something simple and clear such as BUG_ON(go_back <= 0 || go_back > ts.idx) is probably sufficient.
> repeat_test--; > - if (repeat_test <= 0) { > + if (repeat_test <= 0 || go_back < 0) {
The BUG_ON() will mess things up because whatever breakpoints the test is using are still enabled.
If you really want to recover cleanly then perhaps:
+ if (repeat_test <= 0 || WARN_ON(go_back < 0 || go_back > ts.idx)) {
> ts.idx++; > } else { > if (repeat_test % 100 == 0) > v1printk("kgdbts:RUN ... %d remaining\n", repeat_test); > > ts.idx -= go_back; > + if (ts.idx < 0) > + ts.idx = 0;
Not sure about this. If we know the opcodes are bad then re-executing them doesn't seem like a good idea (hence covering it in the WARN_ON branch above).
Daniel.
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