Commit b2a182a4 authored by Douglas Gilbert's avatar Douglas Gilbert Committed by Jens Axboe

sgl_alloc_order: fix memory leak

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: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a48faebe
...@@ -514,7 +514,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length, ...@@ -514,7 +514,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length,
elem_len = min_t(u64, length, PAGE_SIZE << order); elem_len = min_t(u64, length, PAGE_SIZE << order);
page = alloc_pages(gfp, order); page = alloc_pages(gfp, order);
if (!page) { if (!page) {
sgl_free(sgl); sgl_free_order(sgl, order);
return NULL; return NULL;
} }
......
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