On Sat, 4 Jan 2014, John David Anglin wrote: > On 4-Jan-14, at 2:55 PM, Mikulas Patocka wrote: > > > On Sat, 4 Jan 2014, John David Anglin wrote: > > > > > On 4-Jan-14, at 12:45 PM, Mikulas Patocka wrote: > > > > > > > * flush_dcache_page asks for the list of userspace mappings, however > > > > that > > > > page->mapping field is reused by the slab subsystem for a different > > > > purpose. This causes the crash. > > > > > > I'd noticed the other day that the parisc implementation of > > > flush_dcache_page() > > > should return if "!mapping || mapping != page->mapping" is true. This > > > would > > > have avoided crash. > > > > > > Dave > > > > I think no. > > > > page_mapping returns NULL if the page has only anonymous mapping and it is > > not placed in the swap cache. In this case, you need to flush the kernel > > cache. > > > The suggestion is to add the "mapping != page->mapping" to the current NULL > check. > It occurs after the kernel cache flush. "if (!mapping || mapping != page->mapping) return;" returns if the mapping is NULL (and that is wrong because the variable mapping is NULL for anonymous pages). You could probably return "if (!mapping && !PageAnon(page))", but the other architectures aren't doing it. > It doesn't seem right to flush the vma mappings associated with swap address > space > and that appears to be happening with current code. > > Dave > -- > John David Anglin dave.anglin@xxxxxxxx I suppose that "vma_interval_tree_foreach" is empty operation for swap address space. Or isn't it? Mikulas -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
