6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka mpatocka@redhat.com
commit 9793c269da6cd339757de6ba5b2c8681b54c99af upstream.
The commit 5054e778fcd9c ("dm crypt: allocate compound pages if possible") changed dm-crypt to use compound pages to improve performance. Unfortunately, there was an oversight: the allocation of compound pages was not accounted at all. Normal pages are accounted in a percpu counter cc->n_allocated_pages and dm-crypt is limited to allocate at most 2% of memory. Because compound pages were not accounted at all, dm-crypt could allocate memory over the 2% limit.
Fix this by adding the accounting of compound pages, so that memory consumption of dm-crypt is properly limited.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Fixes: 5054e778fcd9c ("dm crypt: allocate compound pages if possible") Cc: stable@vger.kernel.org # v6.5+ Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-crypt.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -1699,11 +1699,17 @@ retry: order = min(order, remaining_order);
while (order > 0) { + if (unlikely(percpu_counter_read_positive(&cc->n_allocated_pages) + + (1 << order) > dm_crypt_pages_per_client)) + goto decrease_order; pages = alloc_pages(gfp_mask | __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | __GFP_COMP, order); - if (likely(pages != NULL)) + if (likely(pages != NULL)) { + percpu_counter_add(&cc->n_allocated_pages, 1 << order); goto have_pages; + } +decrease_order: order--; }
@@ -1741,10 +1747,13 @@ static void crypt_free_buffer_pages(stru
if (clone->bi_vcnt > 0) { /* bio_for_each_folio_all crashes with an empty bio */ bio_for_each_folio_all(fi, clone) { - if (folio_test_large(fi.folio)) + if (folio_test_large(fi.folio)) { + percpu_counter_sub(&cc->n_allocated_pages, + 1 << folio_order(fi.folio)); folio_put(fi.folio); - else + } else { mempool_free(&fi.folio->page, &cc->page_pool); + } } } }