Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
Pre-existing issues: - [High] Framebuffer structure (`fb_info`) Use-After-Free and registration leak if `fb_device_create` fails. - [High] Concurrent sysfs stores and fbdev ioctls cause data races and hardware register clobbering due to missing locks. -- commit 2445fda1d6b2eaa304debdee2b9155ce76236747 Author: Karl Mehltretter <[email protected]> fbdev: sh_mobile_lcdcfb: Restore the per-overlay sysfs attributes This commit restores the per-overlay sysfs attributes by renaming them and registering the sysfs groups on each overlay's framebuffer device instead of the platform driver's dev_groups. It also fixes incorrect dev_get_drvdata() accesses caused by an earlier regression. > diff --git a/drivers/video/fbdev/sh_mobile_lcdcfb.c > b/drivers/video/fbdev/sh_mobile_lcdcfb.c > index e8324b01700f6..5743c96d54814 100644 > --- a/drivers/video/fbdev/sh_mobile_lcdcfb.c > +++ b/drivers/video/fbdev/sh_mobile_lcdcfb.c [ ... ] > @@ -1337,22 +1337,24 @@ overlay_rop3_store(struct device *dev, struct > device_attribute *attr, > return count; > } > > -static DEVICE_ATTR_RW(overlay_alpha); > -static DEVICE_ATTR_RW(overlay_mode); > -static DEVICE_ATTR_RW(overlay_position); > -static DEVICE_ATTR_RW(overlay_rop3); > - > -static struct attribute *overlay_sysfs_attrs[] __maybe_unused = { > - &dev_attr_overlay_alpha.attr, > - &dev_attr_overlay_mode.attr, > - &dev_attr_overlay_position.attr, > - &dev_attr_overlay_rop3.attr, > +static struct device_attribute dev_attr_ovl_alpha = > + __ATTR(ovl_alpha, 0644, overlay_alpha_show, overlay_alpha_store); [Severity: High] This isn't a bug introduced by this patch, but do these sysfs store callbacks need locking to prevent hardware state corruption? Functions like overlay_alpha_store() and overlay_rop3_store() modify overlay state variables and call sh_mobile_lcdc_overlay_setup() to perform direct I/O writes to the LCDC hardware registers without acquiring any locks. Concurrently, standard fbdev ioctls like fb_blank() modify the same state and call sh_mobile_lcdc_overlay_setup() from sh_mobile_lcdc_overlay_blank() while properly holding info->lock. Could concurrent sysfs writes and fbdev ioctls interleave register writes and clobber the hardware state? [ ... ] > @@ -1510,9 +1512,10 @@ sh_mobile_lcdc_overlay_fb_unregister(struct > sh_mobile_lcdc_overlay *ovl) > { > struct fb_info *info = ovl->info; > > - if (info == NULL || info->dev == NULL) > + if (!info || !dev_of_fbinfo(info)) > return; [Severity: High] This is a pre-existing issue, but does this early return cause a memory leak and use-after-free in the fbdev core? If fb_device_create() fails due to memory pressure or sysfs conflicts, info->dev is set to NULL but register_framebuffer() still returns success. When tearing down the device, this check for dev_of_fbinfo() evaluates to true and causes an early return, bypassing unregister_framebuffer(). Later, sh_mobile_lcdc_overlay_fb_cleanup() calls framebuffer_release(), which frees the fb_info structure while it is still linked in the fbdev core's registered_fb array. Can unregister_framebuffer() be called regardless of whether device creation succeeded, both here and in sh_mobile_lcdc_channel_fb_unregister()? > > + device_remove_groups(dev_of_fbinfo(info), overlay_sysfs_groups); > unregister_framebuffer(ovl->info); > } -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=1
