From c421c082088ef10baec2612cea5973907a6acc21 Mon Sep 17 00:00:00 2001 From: Douglas Gilbert Date: Thu, 15 Oct 2020 14:57:35 -0400 Subject: [PATCH] sgl_alloc_order: fix memory leak [ Upstream commit b2a182a40278bc5849730e66bca01a762188ed86 ] sgl_alloc_order() can fail when 'length' is large on a memory constrained system. When order > 0 it will potentially be making several multi-page allocations with the later ones more likely to fail than the earlier one. So it is important that sgl_alloc_order() frees up any pages it has obtained before returning NULL. In the case when order > 0 it calls the wrong free page function and leaks. In testing the leak was sufficient to bring down my 8 GiB laptop with OOM. Reviewed-by: Bart Van Assche Signed-off-by: Douglas Gilbert Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- lib/scatterlist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 5813072bc589..29346184fcf2 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -514,7 +514,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length, elem_len = min_t(u64, length, PAGE_SIZE << order); page = alloc_pages(gfp, order); if (!page) { - sgl_free(sgl); + sgl_free_order(sgl, order); return NULL; }