The system dma-buf heap lets userspace allocate buffers from the page
allocator. However, these allocations are not accounted for in memcg,
allowing processes to escape limits that may be configured.

Pass __GFP_ACCOUNT for system heap allocations, based on the
dma_heap.mem_accounting parameter, to use memcg and account for them.

Signed-off-by: Eric Chanudet <echanude@redhat.com>
---
 drivers/dma-buf/heaps/system_heap.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 4c782fe33fd497a74eb5065797259576f9b651b6..4049d042afa14ec2f4d034f59f1740600a20c1e5 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -320,14 +320,17 @@ static struct page *alloc_largest_available(unsigned long size,
 {
 	struct page *page;
 	int i;
+	gfp_t flags;
 
 	for (i = 0; i < NUM_ORDERS; i++) {
 		if (size <  (PAGE_SIZE << orders[i]))
 			continue;
 		if (max_order < orders[i])
 			continue;
-
-		page = alloc_pages(order_flags[i], orders[i]);
+		flags = order_flags[i];
+		if (mem_accounting)
+			flags |= __GFP_ACCOUNT;
+		page = alloc_pages(flags, orders[i]);
 		if (!page)
 			continue;
 		return page;

-- 
2.52.0

On Fri, Jan 16, 2026 at 12:06 PM Eric Chanudet <echanude@redhat.com> wrote:
>
> The system dma-buf heap lets userspace allocate buffers from the page
> allocator. However, these allocations are not accounted for in memcg,
> allowing processes to escape limits that may be configured.
>
> Pass __GFP_ACCOUNT for system heap allocations, based on the
> dma_heap.mem_accounting parameter, to use memcg and account for them.
>
> Signed-off-by: Eric Chanudet <echanude@redhat.com>

Reviewed-by: T.J. Mercier <tjmercier@google.com>

Hello Eric,

On Sat, 17 Jan 2026 at 04:07, T.J. Mercier <tjmercier@google.com> wrote:
>
> On Fri, Jan 16, 2026 at 12:06 PM Eric Chanudet <echanude@redhat.com> wrote:
> >
> > The system dma-buf heap lets userspace allocate buffers from the page
> > allocator. However, these allocations are not accounted for in memcg,
> > allowing processes to escape limits that may be configured.
> >
> > Pass __GFP_ACCOUNT for system heap allocations, based on the
> > dma_heap.mem_accounting parameter, to use memcg and account for them.
> >
> > Signed-off-by: Eric Chanudet <echanude@redhat.com>
>
> Reviewed-by: T.J. Mercier <tjmercier@google.com>

Thank you for the series; LGTM, I'll push it tonight to drm-misc-next.

Best,
Sumit.