alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate

alloc_pages_bulk_node() may partially succeed and allocate fewer than the
requested nr_pages.  There are several conditions under which this can
occur, but we have encountered the case where CONFIG_PAGE_OWNER is enabled
causing all bulk allocations to always fallback to single page allocations
due to commit 187ad460b841 ("mm/page_alloc: avoid page allocator recursion
with pagesets.lock held").

Currently vm_module_tags_populate() immediately fails when
alloc_pages_bulk_node() returns fewer than the requested number of pages.
When this happens memory allocation profiling gets disabled, for example

[   14.297583] [9:       modprobe:  465] Failed to allocate memory for allocation tags in the module scsc_wlan. Memory allocation profiling is disabled!
[   14.299339] [9:       modprobe:  465] modprobe: Failed to insmod '/vendor/lib/modules/scsc_wlan.ko' with args '': Out of memory

This patch causes vm_module_tags_populate() to retry bulk allocations for
the remaining memory instead of failing immediately which will avoid the
disablement of memory allocation profiling.

Link: https://lkml.kernel.org/r/20250409225111.3770347-1-tjmercier@google.com
Fixes: 0f9b685626da ("alloc_tag: populate memory for module tags as needed")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Reported-by: Janghyuck Kim <janghyuck.kim@samsung.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
index 1d893e31361493326bd65996beef0fcfd9d20fa6..25ecc1334b67ddd238b86d2ec785d1b6b3b7ce85 100644 (file)
--- a/lib/alloc_tag.c
+++ b/lib/alloc_tag.c
@@ -422,11 +422,20 @@ static int vm_module_tags_populate(void)
                unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN);
                unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN);
                unsigned long more_pages;
-               unsigned long nr;
+               unsigned long nr = 0;
 
                more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT;
-               nr = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,
-                                          NUMA_NO_NODE, more_pages, next_page);
+               while (nr < more_pages) {
+                       unsigned long allocated;
+
+                       allocated = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,
+                               NUMA_NO_NODE, more_pages - nr, next_page + nr);
+
+                       if (!allocated)
+                               break;
+                       nr += allocated;
+               }
+
                if (nr < more_pages ||
                    vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL,
                                     next_page, PAGE_SHIFT) < 0) {