From: Xiaomeng Tong xiam0nd.tong@gmail.com
[ Upstream commit 5ac11fe03a0a83042d1a040dbce4fa2fb5521e23 ]
The bug is here: if (!buf) {
The list iterator value 'buf' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty (in this case, the check 'if (!buf) {' will always be false and never exit expectly).
To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'buf' as a dedicated pointer to point to the found element.
Fixes: 2419e55e532de ("misc: fastrpc: add mmap/unmap support") Signed-off-by: Xiaomeng Tong xiam0nd.tong@gmail.com Link: https://lore.kernel.org/r/20220327062202.5720-1-xiam0nd.tong@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/misc/fastrpc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index d0471fec37fb..65f24b6150aa 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -1349,17 +1349,18 @@ static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, struct fastrpc_req_munmap *req) { struct fastrpc_invoke_args args[1] = { [0] = { 0 } }; - struct fastrpc_buf *buf, *b; + struct fastrpc_buf *buf = NULL, *iter, *b; struct fastrpc_munmap_req_msg req_msg; struct device *dev = fl->sctx->dev; int err; u32 sc;
spin_lock(&fl->lock); - list_for_each_entry_safe(buf, b, &fl->mmaps, node) { - if ((buf->raddr == req->vaddrout) && (buf->size == req->size)) + list_for_each_entry_safe(iter, b, &fl->mmaps, node) { + if ((iter->raddr == req->vaddrout) && (iter->size == req->size)) { + buf = iter; break; - buf = NULL; + } } spin_unlock(&fl->lock);