> On Fri, 2015-01-30 at 19:08 +0700, Arseny Solokha wrote: >> MMU_NO_CONTEXT is conditionally defined as 0 or (unsigned int)-1. > > For nohash it is specifically -1.
>> However, in __flush_tlb_page() a corresponding variable is only tested >> for open coded 0, which can cause NULL pointer dereference if `mm' >> argument was legitimately passed as such. >> >> Bail out early in case the first argument is NULL, thus eliminate confusion >> between different values of MMU_NO_CONTEXT and avoid disabling and then >> re-enabling preemption unnecessarily. > > How did you notice this? Did you see an oops, or was it code > inspection? I'm wondering what codepath gets here with mm == NULL. Just a code inspection. It didn't seemed right at the first glance. Arsény > > -Scott -- 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/
