From 2e11f8296d22134c4fca7eb022eea2b09facd307 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 21 Aug 2014 11:09:17 -0500 Subject: [PATCH] nfs: cap request size to fit a kmalloced page array pNFS servers may return arbitrarily large layouts. Trim back the I/O size to one that we can at least allocate the page array for. Signed-off-by: Christoph Hellwig Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index be7cbce6e4c7..94e16ec88312 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -481,6 +481,14 @@ size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, return 0; } + /* + * Limit the request size so that we can still allocate a page array + * for it without upsetting the slab allocator. + */ + if (((desc->pg_count + req->wb_bytes) >> PAGE_SHIFT) * + sizeof(struct page) > PAGE_SIZE) + return 0; + return min(desc->pg_bsize - desc->pg_count, (size_t)req->wb_bytes); } EXPORT_SYMBOL_GPL(nfs_generic_pg_test); -- 2.20.1