From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54400) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1daYl9-0005En-Ec for qemu-devel@nongnu.org; Wed, 26 Jul 2017 22:42:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1daYl8-0007gC-PM for qemu-devel@nongnu.org; Wed, 26 Jul 2017 22:42:43 -0400 Sender: =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Wed, 26 Jul 2017 23:42:08 -0300 Message-Id: <20170727024224.22900-4-f4bug@amsat.org> In-Reply-To: <20170727024224.22900-1-f4bug@amsat.org> References: <20170727024224.22900-1-f4bug@amsat.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH for 2.10 v2 03/20] ivshmem: fix incorrect error handling in ivshmem_recv_msg() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini , Eric Blake , Markus Armbruster Cc: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, qemu-trivial@nongnu.org Screwed up in commit 3a55fc0f, v2.6.0. If qemu_chr_fe_read_all() returns -EINTR the do {} statement continues and the n accumulator used to complete reads upto sizeof(msg) is decremented by 4 (the value of EINTR on Linux). To avoid that, use simpler if() statements and continue if EINTR occured. hw/misc/ivshmem.c:650:14: warning: Loss of sign in implicit conversion } while (n < sizeof(msg)); ^ Reported-by: Clang Static Analyzer Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Markus Armbruster --- hw/misc/ivshmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c index a58f9ee579..47a015f072 100644 --- a/hw/misc/ivshmem.c +++ b/hw/misc/ivshmem.c @@ -642,7 +642,10 @@ static int64_t ivshmem_recv_msg(IVShmemState *s, int *pfd, Error **errp) do { ret = qemu_chr_fe_read_all(&s->server_chr, (uint8_t *)&msg + n, sizeof(msg) - n); - if (ret < 0 && ret != -EINTR) { + if (ret < 0) { + if (ret == -EINTR) { + continue; + } error_setg_errno(errp, -ret, "read from server failed"); return INT64_MIN; } -- 2.13.3