This is a note to let you know that I've just added the patch titled qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute to the 4.9-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: qemu_fw_cfg-make-fw_cfg_rev_attr-a-proper-kobj_attribute.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fca41af18e10318e4de090db47d9fa7169e1bf2f Mon Sep 17 00:00:00 2001 From: Nathan Chancellor <nathan@xxxxxxxxxx> Date: Thu, 11 Feb 2021 12:42:58 -0700 Subject: qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Nathan Chancellor <nathan@xxxxxxxxxx> commit fca41af18e10318e4de090db47d9fa7169e1bf2f upstream. fw_cfg_showrev() is called by an indirect call in kobj_attr_show(), which violates clang's CFI checking because fw_cfg_showrev()'s second parameter is 'struct attribute', whereas the ->show() member of 'struct kobj_structure' expects the second parameter to be of type 'struct kobj_attribute'. $ cat /sys/firmware/qemu_fw_cfg/rev 3 $ dmesg | grep "CFI failure" [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8): Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where this would have been caught automatically by the incompatible pointer types compiler warning. Update fw_cfg_showrev() accordingly. Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device") Link: https://github.com/ClangBuiltLinux/linux/issues/1299 Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20210211194258.4137998-1-nathan@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/firmware/qemu_fw_cfg.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/firmware/qemu_fw_cfg.c +++ b/drivers/firmware/qemu_fw_cfg.c @@ -192,15 +192,13 @@ static int fw_cfg_do_platform_probe(stru /* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */ static u32 fw_cfg_rev; -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf) +static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a, + char *buf) { return sprintf(buf, "%u\n", fw_cfg_rev); } -static const struct { - struct attribute attr; - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf); -} fw_cfg_rev_attr = { +static const struct kobj_attribute fw_cfg_rev_attr = { .attr = { .name = "rev", .mode = S_IRUSR }, .show = fw_cfg_showrev, }; Patches currently in stable-queue which might be from nathan@xxxxxxxxxx are queue-4.9/qemu_fw_cfg-make-fw_cfg_rev_attr-a-proper-kobj_attribute.patch queue-4.9/powerpc-barrier-avoid-collision-with-clang-s-__lwsync-macro.patch