This is a note to let you know that I've just added the patch titled
dm crypt: account large pages in cc->n_allocated_pages
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-crypt-account-large-pages-in-cc-n_allocated_pages.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9793c269da6cd339757de6ba5b2c8681b54c99af Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Tue, 31 Oct 2023 19:12:54 +0100
Subject: dm crypt: account large pages in cc->n_allocated_pages
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
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@xxxxxxxxxx>
Fixes: 5054e778fcd9c ("dm crypt: allocate compound pages if possible")
Cc: stable@xxxxxxxxxxxxxxx # v6.5+
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
+ }
}
}
}
Patches currently in stable-queue which might be from mpatocka@xxxxxxxxxx are
queue-6.6/dm-crypt-account-large-pages-in-cc-n_allocated_pages.patch
