This is a note to let you know that I've just added the patch titled
um: virt-pci: Avoid GCC non-NULL warning
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
um-virt-pci-avoid-gcc-non-null-warning.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.
>From bdc77507fecd00ddad2f502f86a48a9ec38f0f84 Mon Sep 17 00:00:00 2001
From: Kees Cook <keesc...@chromium.org>
Date: Thu, 1 Dec 2022 16:23:25 -0800
Subject: um: virt-pci: Avoid GCC non-NULL warning
From: Kees Cook <keesc...@chromium.org>
commit bdc77507fecd00ddad2f502f86a48a9ec38f0f84 upstream.
GCC gets confused about the return value of get_cpu_var() possibly
being NULL, so explicitly test for it before calls to memcpy() and
memset(). Avoids warnings like this:
arch/um/drivers/virt-pci.c: In function 'um_pci_send_cmd':
include/linux/fortify-string.h:48:33: warning: argument 1 null where
non-null expected [-Wnonnull]
48 | #define __underlying_memcpy __builtin_memcpy
| ^
include/linux/fortify-string.h:438:9: note: in expansion of macro
'__underlying_memcpy'
438 | __underlying_##op(p, q, __fortify_size);
\
| ^~~~~~~~~~~~~
include/linux/fortify-string.h:483:26: note: in expansion of macro
'__fortify_memcpy_chk'
483 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s,
\
| ^~~~~~~~~~~~~~~~~~~~
arch/um/drivers/virt-pci.c:100:9: note: in expansion of macro 'memcpy'
100 | memcpy(buf, cmd, cmd_size);
| ^~~~~~
While at it, avoid literal "8" and use stored sizeof(buf->data) in
memset() and um_pci_send_cmd().
Reported-by: kernel test robot <l...@intel.com>
Link: https://lore.kernel.org/lkml/202211271212.suzsc9f9-...@intel.com
Fixes: ba38961a069b ("um: Enable FORTIFY_SOURCE")
Cc: Richard Weinberger <rich...@nod.at>
Cc: Anton Ivanov <anton.iva...@cambridgegreys.com>
Cc: Johannes Berg <johan...@sipsolutions.net>
Cc: "Michael S. Tsirkin" <m...@redhat.com>
Cc: Al Viro <v...@zeniv.linux.org.uk>
Cc: Xiu Jianfeng <xiujianf...@huawei.com>
Cc: Vincent Whitchurch <vincent.whitchu...@axis.com>
Cc: linux-um@lists.infradead.org
Cc: sta...@vger.kernel.org
Signed-off-by: Kees Cook <keesc...@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/um/drivers/virt-pci.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/um/drivers/virt-pci.c
+++ b/arch/um/drivers/virt-pci.c
@@ -97,7 +97,8 @@ static int um_pci_send_cmd(struct um_pci
}
buf = get_cpu_var(um_pci_msg_bufs);
- memcpy(buf, cmd, cmd_size);
+ if (buf)
+ memcpy(buf, cmd, cmd_size);
if (posted) {
u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC);
@@ -182,6 +183,7 @@ static unsigned long um_pci_cfgspace_rea
struct um_pci_message_buffer *buf;
u8 *data;
unsigned long ret = ULONG_MAX;
+ size_t bytes = sizeof(buf->data);
if (!dev)
return ULONG_MAX;
@@ -189,7 +191,8 @@ static unsigned long um_pci_cfgspace_rea
buf = get_cpu_var(um_pci_msg_bufs);
data = buf->data;
- memset(buf->data, 0xff, sizeof(buf->data));
+ if (buf)
+ memset(data, 0xff, bytes);
switch (size) {
case 1:
@@ -204,7 +207,7 @@ static unsigned long um_pci_cfgspace_rea
goto out;
}
- if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, 8))
+ if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, bytes))
goto out;
switch (size) {
Patches currently in stable-queue which might be from keesc...@chromium.org are
queue-6.1/um-virt-pci-avoid-gcc-non-null-warning.patch
queue-6.1/random-add-helpers-for-random-numbers-with-given-floor-or-range.patch
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