The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Thanks, Sasha

------------------ original commit in Linus's tree ------------------

From 38b43539d64b2fa020b3b9a752a986769f87f7a6 Mon Sep 17 00:00:00 2001 From: Tony Battersby tonyb@cybernetics.com Date: Thu, 29 Feb 2024 13:08:09 -0500 Subject: [PATCH] block: Fix page refcounts for unaligned buffers in __bio_release_pages()

Fix an incorrect number of pages being released for buffers that do not start at the beginning of a page.

Fixes: 1b151e2435fc ("block: Remove special-casing of compound pages") Cc: stable@vger.kernel.org Signed-off-by: Tony Battersby tonyb@cybernetics.com Tested-by: Greg Edwards gedwards@ddn.com Link: https://lore.kernel.org/r/86e592a9-98d4-4cff-a646-0c0084328356@cybernetics.c... Signed-off-by: Jens Axboe axboe@kernel.dk --- block/bio.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/block/bio.c b/block/bio.c index 496867b51609f..a8b6919400270 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1153,7 +1153,7 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty)

bio_for_each_folio_all(fi, bio) { struct page *page; - size_t done = 0; + size_t nr_pages;

if (mark_dirty) { folio_lock(fi.folio); @@ -1161,10 +1161,11 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty) folio_unlock(fi.folio); } page = folio_page(fi.folio, fi.offset / PAGE_SIZE); + nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE - + fi.offset / PAGE_SIZE + 1; do { bio_release_page(bio, page++); - done += PAGE_SIZE; - } while (done < fi.length); + } while (--nr_pages != 0); } } EXPORT_SYMBOL_GPL(__bio_release_pages);