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When building s390 allmodconfig after commit9b91a65230("usb: gadget: uvc: increase worker prio to WQ_HIGHPRI"), the following error occurs: In file included from ../include/linux/string.h:253, from ../include/linux/bitmap.h:11, from ../include/linux/cpumask.h:12, from ../include/linux/smp.h:13, from ../include/linux/lockdep.h:14, from ../include/linux/rcupdate.h:29, from ../include/linux/rculist.h:11, from ../include/linux/pid.h:5, from ../include/linux/sched.h:14, from ../include/linux/ratelimit.h:6, from ../include/linux/dev_printk.h:16, from ../include/linux/device.h:15, from ../drivers/usb/gadget/function/f_uvc.c:9: In function ‘fortify_memset_chk’, inlined from ‘uvc_register_video’ at ../drivers/usb/gadget/function/f_uvc.c:424:2: ../include/linux/fortify-string.h:301:25: error: call to ‘__write_overflow_field’ declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning] 301 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This points to the memset() in uvc_register_video(). It is clear that the argument to sizeof() is incorrect, as uvc->vdev (a 'struct video_device') is being zeroed out but the size of uvc->video (a 'struct uvc_video') is being used as the third arugment to memset(). pahole shows that prior to commit9b91a65230("usb: gadget: uvc: increase worker prio to WQ_HIGHPRI"), 'struct video_device' and 'struct ucv_video' had the same size, meaning that the argument to sizeof() is incorrect semantically but there is no visible issue: $ pahole -s build/drivers/usb/gadget/function/f_uvc.o | grep -E "(uvc_video|video_device)\s+" video_device 1400 4 uvc_video 1400 3 After that change, uvc_video becomes slightly larger, meaning that the memset() will overwrite by 8 bytes: $ pahole -s build/drivers/usb/gadget/function/f_uvc.o | grep -E "(uvc_video|video_device)\s+" video_device 1400 4 uvc_video 1408 3 Fix the arugment to sizeof() so that there is no overwrite. Cc: stable@vger.kernel.org Fixes:e4ce9ed835("usb: gadget: uvc: ensure the vdev is unset") Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220928201921.3152163-1-nathan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.