From fe2c34bab6d46469ad3095955dc37e984dc24e38 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Fri, 17 Nov 2023 13:38:46 -0800 Subject: iov_iter: fix copy_page_to_iter_nofault() The recent conversion to inline functions made two mistakes: 1. It tries to copy the full amount requested (bytes), not just what's available in the kmap'd page (n). 2. It's not applying the offset in the first page. Note that copy_page_to_iter_nofault() is only used by /proc/kcore. This was detected by drgn's test suite. Fixes: f1982740f5e7 ("iov_iter: Convert iterate*() to inline funcs") Signed-off-by: Omar Sandoval Link: https://lore.kernel.org/r/c1616e06b5248013cbbb1881bb4fef85a7a69ccb.1700257019.git.osandov@fb.com Acked-by: David Howells Signed-off-by: Christian Brauner --- lib/iov_iter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/iov_iter.c') diff --git a/lib/iov_iter.c b/lib/iov_iter.c index de7d11cf4c63..8ff6824a1005 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -409,7 +409,7 @@ size_t copy_page_to_iter_nofault(struct page *page, unsigned offset, size_t byte void *kaddr = kmap_local_page(page); size_t n = min(bytes, (size_t)PAGE_SIZE - offset); - n = iterate_and_advance(i, bytes, kaddr, + n = iterate_and_advance(i, n, kaddr + offset, copy_to_user_iter_nofault, memcpy_to_iter); kunmap_local(kaddr); -- cgit