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: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Douglas Gilbert 2020-10-15 14:57:35 -04:00 committed by Jens Axboe
parent a48faebe65
commit b2a182a402

View File

@ -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;
}