Messages in this thread Patch in this message | | | From | "Fabio M. De Francesco" <> | Subject | [RFC PATCH] mm/highmem: VM_BUG_ON() if offset + len > PAGE_SIZE | Date | Sun, 24 Apr 2022 12:48:06 +0200 |
| |
Call VM_BUG_ON() if offset + len > PAGE_SIZE.
This is an RFC patch because I'm not sure if we actually need to BUG_ON(), so I'd like to know what Maintainers and other developers think about this proposal.
Please note that memset_page() uses VM_BUG_ON() to prevent the same issue.
Furthermore, I also cannot understand why memset_page() does not call flush_dcache_page() after memset() but I suppose that the different implementations of these two functions should be addressed in another RFC.
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> --- include/linux/highmem.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index c3d562b5f0c1..bdb16d5f8148 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -349,6 +349,8 @@ static inline void memcpy_to_page(struct page *page, size_t offset, static inline void memzero_page(struct page *page, size_t offset, size_t len) { char *addr = kmap_local_page(page); + + VM_BUG_ON(offset + len > PAGE_SIZE); memset(addr + offset, 0, len); flush_dcache_page(page); kunmap_local(addr); -- 2.34.1
| |