Re: Kernel oops with 6.14 when enabling TLS
From: Matthew Wilcox <willy@infradead.org>
Date: 2025-03-04 18:06:41
Also in:
linux-block, linux-mm, linux-nvme
Subsystem:
library code, memory management - core, the rest, userspace copyin/copyout (uiovec) · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds, Alexander Viro
On Tue, Mar 04, 2025 at 04:53:09PM +0000, Matthew Wilcox wrote:
Right, that's what happened in the block layer. We mark the bio with BIO_PAGE_PINNED if the pincount needs to be dropped. As a transitional period, we had BIO_PAGE_REFFED which indicated that the page refcount needed to be dropped. Perhaps there's something similar that network could be doing.
Until that time ... how does this look as a quick hack to avoid reverting the slab change?
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d6fed25243c3..ca08a923ac6d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -1520,7 +1520,10 @@ static inline void folio_get(struct folio *folio) static inline void get_page(struct page *page) { - folio_get(page_folio(page)); + struct folio *folio = page_folio(page); + if (WARN_ON_ONCE(folio_test_slab(folio))) + return; + folio_get(folio); } static inline __must_check bool try_get_page(struct page *page)
@@ -1614,6 +1617,8 @@ static inline void put_page(struct page *page) { struct folio *folio = page_folio(page); + if (folio_test_slab(folio)) + return; folio_put(folio); }
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 65f550cb5081..8c7fdb7d8c8f 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c@@ -1190,8 +1190,12 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, if (!n) return -ENOMEM; p = *pages; - for (int k = 0; k < n; k++) - get_page(p[k] = page + k); + for (int k = 0; k < n; k++) { + struct folio *folio = page_folio(page); + p[k] = page + k; + if (!folio_test_slab(folio)) + folio_get(folio); + } maxsize = min_t(size_t, maxsize, n * PAGE_SIZE - *start); i->count -= maxsize; i->iov_offset += maxsize;