On Tue, Dec 28, 2010 at 2:18 PM, Ohad Ben-Cohen <ohad@xxxxxxxxxx> wrote: > On Tue, Dec 28, 2010 at 2:12 PM, Felipe Contreras > <felipe.contreras@xxxxxxxxx> wrote: >> I haven't investigated why that happens, but kernel-space should not >> panic regardless of what user-space does. > > Agree of course. But that's not what we were discussing... Well, hopefully after applying your patch it would be easier to figure that out. >>> Anyhow, a thread that is calling proc_*_dma() will both increase the >>> reference count and decrease it back before going back to user space. >>> Otherwise your patch would be problematic as well - who will unlock >>> the mutex you take in proc_*_dma() ? >> >> I'm saying that user-space might crash *before* proc_*_dma() finishes, >> before the reference count has been decreased. >> >> In my patch there would be no issue because proc_un_map() would wait >> until proc_*_dma() has released the lock. > > But what will happen if, as you say, user-space would crash before > proc_*_dma() has released the lock ? how could proc_un_map() run ? user-space crashed, not kernel-space; the code would continue to run and eventually release the lock. > This is all good, and I have no problem with it. As I said, I don't > resist your patch as a temporary fix. But it doesn't mean I like it... Yeah, so the chances of getting this fixed on 2.6.37 are dimmed. -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
