From: Takashi Iwai Date: Sun, 29 Jan 2023 08:28:56 +0000 (+0100) Subject: fbdev: Fix invalid page access after closing deferred I/O devices X-Git-Tag: v6.6.17~4688^2^2~84 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3efc61d95259956db25347e2a9562c3e54546e20;p=platform%2Fkernel%2Flinux-rpi.git fbdev: Fix invalid page access after closing deferred I/O devices When a fbdev with deferred I/O is once opened and closed, the dirty pages still remain queued in the pageref list, and eventually later those may be processed in the delayed work. This may lead to a corruption of pages, hitting an Oops. This patch makes sure to cancel the delayed work and clean up the pageref list at closing the device for addressing the bug. A part of the cleanup code is factored out as a new helper function that is called from the common fb_release(). Reviewed-by: Patrik Jakobsson Cc: Signed-off-by: Takashi Iwai Tested-by: Miko Larsson Fixes: 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct") Reviewed-by: Thomas Zimmermann Signed-off-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20230129082856.22113-1-tiwai@suse.de --- diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c index c730253..583cbcf 100644 --- a/drivers/video/fbdev/core/fb_defio.c +++ b/drivers/video/fbdev/core/fb_defio.c @@ -313,7 +313,7 @@ void fb_deferred_io_open(struct fb_info *info, } EXPORT_SYMBOL_GPL(fb_deferred_io_open); -void fb_deferred_io_cleanup(struct fb_info *info) +void fb_deferred_io_release(struct fb_info *info) { struct fb_deferred_io *fbdefio = info->fbdefio; struct page *page; @@ -327,6 +327,14 @@ void fb_deferred_io_cleanup(struct fb_info *info) page = fb_deferred_io_page(info, i); page->mapping = NULL; } +} +EXPORT_SYMBOL_GPL(fb_deferred_io_release); + +void fb_deferred_io_cleanup(struct fb_info *info) +{ + struct fb_deferred_io *fbdefio = info->fbdefio; + + fb_deferred_io_release(info); kvfree(info->pagerefs); mutex_destroy(&fbdefio->lock); diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 3a6c845..ab3545a 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1454,6 +1454,10 @@ __releases(&info->lock) struct fb_info * const info = file->private_data; lock_fb_info(info); +#if IS_ENABLED(CONFIG_FB_DEFERRED_IO) + if (info->fbdefio) + fb_deferred_io_release(info); +#endif if (info->fbops->fb_release) info->fbops->fb_release(info,1); module_put(info->fbops->owner); diff --git a/include/linux/fb.h b/include/linux/fb.h index 96b9632..73eb1f8 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -662,6 +662,7 @@ extern int fb_deferred_io_init(struct fb_info *info); extern void fb_deferred_io_open(struct fb_info *info, struct inode *inode, struct file *file); +extern void fb_deferred_io_release(struct fb_info *info); extern void fb_deferred_io_cleanup(struct fb_info *info); extern int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync);