mm/memblock.c: warn if zero alignment was requested

rppt · torvalds · commit 2f770806fd2c · 2018-10-31T08:54:17.000-07:00
After updating all memblock users to explicitly specify SMP_CACHE_BYTES alignment rather than use 0, it is still possible that uncovered users may sneak in. Add a WARN_ON_ONCE for such cases. [sfr@canb.auug.org.au: use dump_stack() instead of WARN_ON_ONCE for the alignment checks] Link: http://lkml.kernel.org/r/20181016131927.6ceba6ab@canb.auug.org.au [akpm@linux-foundation.org: add apologetic comment] Link: http://lkml.kernel.org/r/20181011060850.GA19822@rapoport-lnx Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memblock.c b/mm/memblock.c
@@ -1247,6 +1247,12 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
 {
 	phys_addr_t found;
 
+	if (!align) {
+		/* Can't use WARNs this early in boot on powerpc */
+		dump_stack();
+		align = SMP_CACHE_BYTES;
+	}
+
 	found = memblock_find_in_range_node(size, align, start, end, nid,
 					    flags);
 	if (found && !memblock_reserve(found, size)) {
@@ -1369,6 +1375,11 @@ static void * __init memblock_alloc_internal(
 	if (WARN_ON_ONCE(slab_is_available()))
 		return kzalloc_node(size, GFP_NOWAIT, nid);
 
+	if (!align) {
+		dump_stack();
+		align = SMP_CACHE_BYTES;
+	}
+
 	if (max_addr > memblock.current_limit)
 		max_addr = memblock.current_limit;
 again:
