A few fixes for drm panic, that I found when writing unit tests with kunit.
Jocelyn Falempe (6): drm/panic: Fix drawing the logo on a small narrow screen drm/panic: Fix overlap between qr code and logo drm/panic: Fix qr_code, ensure vmargin is positive drm/panic: Fix kmsg text drawing rectangle drm/panic: Fix divide by 0 if the screen width < font width drm/panic: Fix 24bit pixel crossing page boundaries
drivers/gpu/drm/drm_panic.c | 60 +++++++++++++++++++++++++++++++++---- 1 file changed, 54 insertions(+), 6 deletions(-)
base-commit: e4bea919584ff292c9156cf7d641a2ab3cbe27b0
If the logo width is bigger than the framebuffer width, and the height is big enough to hold the logo and the message, it will draw at x coordinate that are higher than the width, and ends up in a corrupted image.
Fixes: 4b570ac2eb54 ("drm/rect: Add drm_rect_overlap()") Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_panic.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 1d6312fa1429..23ba791c6131 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -429,6 +429,9 @@ static void drm_panic_logo_rect(struct drm_rect *rect, const struct font_desc *f static void drm_panic_logo_draw(struct drm_scanout_buffer *sb, struct drm_rect *rect, const struct font_desc *font, u32 fg_color) { + if (rect->x2 > sb->width || rect->y2 > sb->height) + return; + if (logo_mono) drm_panic_blit(sb, rect, logo_mono->data, DIV_ROUND_UP(drm_rect_width(rect), 8), 1, fg_color);
The borders of the qr code was not taken into account to check if it overlap with the logo, leading to the logo being partially covered.
Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_panic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 23ba791c6131..179cbf21f22d 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -749,7 +749,7 @@ static int _draw_panic_static_qr_code(struct drm_scanout_buffer *sb) /* Fill with the background color, and draw text on top */ drm_panic_fill(sb, &r_screen, bg_color);
- if (!drm_rect_overlap(&r_logo, &r_msg) && !drm_rect_overlap(&r_logo, &r_qr)) + if (!drm_rect_overlap(&r_logo, &r_msg) && !drm_rect_overlap(&r_logo, &r_qr_canvas)) drm_panic_logo_draw(sb, &r_logo, font, fg_color);
draw_txt_rectangle(sb, font, panic_msg, panic_msg_lines, true, &r_msg, fg_color);
Hi,
Thanks for your patch.
FYI: kernel test robot notices the stable kernel rule is not satisfied.
The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#opti...
Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree. Subject: [PATCH 2/6] drm/panic: Fix overlap between qr code and logo Link: https://lore.kernel.org/stable/20251009122955.562888-3-jfalempe%40redhat.com
Depending on qr_code size and screen size, the vertical margin can be negative, that means there is not enough room to draw the qr_code.
So abort early, to avoid a segfault by trying to draw at negative coordinates.
Fixes: cb5164ac43d0f ("drm/panic: Add a QR code panic screen") Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_panic.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 179cbf21f22d..281bb2dabf81 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -736,7 +736,10 @@ static int _draw_panic_static_qr_code(struct drm_scanout_buffer *sb) pr_debug("QR width %d and scale %d\n", qr_width, scale); r_qr_canvas = DRM_RECT_INIT(0, 0, qr_canvas_width * scale, qr_canvas_width * scale);
- v_margin = (sb->height - drm_rect_height(&r_qr_canvas) - drm_rect_height(&r_msg)) / 5; + v_margin = sb->height - drm_rect_height(&r_qr_canvas) - drm_rect_height(&r_msg); + if (v_margin < 0) + return -ENOSPC; + v_margin /= 5;
drm_rect_translate(&r_qr_canvas, (sb->width - r_qr_canvas.x2) / 2, 2 * v_margin); r_qr = DRM_RECT_INIT(r_qr_canvas.x1 + QR_MARGIN * scale, r_qr_canvas.y1 + QR_MARGIN * scale,
The rectangle height was larger than the screen size. This has no real impact.
Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_panic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 281bb2dabf81..69be9d835ccf 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -480,7 +480,7 @@ static int draw_line_with_wrap(struct drm_scanout_buffer *sb, const struct font_ struct drm_panic_line *line, int yoffset, u32 fg_color) { int chars_per_row = sb->width / font->width; - struct drm_rect r_txt = DRM_RECT_INIT(0, yoffset, sb->width, sb->height); + struct drm_rect r_txt = DRM_RECT_INIT(0, yoffset, sb->width, font->height); struct drm_panic_line line_wrap;
if (line->len > chars_per_row) {
In the unlikely case that the screen is tiny, and smaller than the font width, it leads to a divide by 0:
draw_line_with_wrap() chars_per_row = sb->width / font->width = 0 line_wrap.len = line->len % chars_per_row;
This will trigger a divide by 0
Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_panic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 69be9d835ccf..bc5158683b2b 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -523,7 +523,7 @@ static void draw_panic_static_kmsg(struct drm_scanout_buffer *sb) struct drm_panic_line line; int yoffset;
- if (!font) + if (!font || font->width > sb->width) return;
yoffset = sb->height - font->height - (sb->height % font->height) / 2;
When using page list framebuffer, and using RGB888 format, some pixels can cross the page boundaries, and this case was not handled, leading to writing 1 or 2 bytes on the next virtual address.
Add a check and a specific function to handle this case.
Fixes: c9ff2808790f0 ("drm/panic: Add support to scanout buffer as array of pages") Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_panic.c | 46 +++++++++++++++++++++++++++++++++++-- 1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index bc5158683b2b..d4b6ea42db0f 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -174,6 +174,33 @@ static void drm_panic_write_pixel24(void *vaddr, unsigned int offset, u32 color) *p = color & 0xff; }
+/* + * Special case if the pixel crosses page boundaries + */ +static void drm_panic_write_pixel24_xpage(void *vaddr, struct page *next_page, + unsigned int offset, u32 color) +{ + u8 *vaddr2; + u8 *p = vaddr + offset; + + vaddr2 = kmap_local_page_try_from_panic(next_page); + + *p++ = color & 0xff; + color >>= 8; + + if (offset == PAGE_SIZE - 1) + p = vaddr2; + + *p++ = color & 0xff; + color >>= 8; + + if (offset == PAGE_SIZE - 2) + p = vaddr2; + + *p = color & 0xff; + kunmap_local(vaddr2); +} + static void drm_panic_write_pixel32(void *vaddr, unsigned int offset, u32 color) { u32 *p = vaddr + offset; @@ -231,7 +258,14 @@ static void drm_panic_blit_page(struct page **pages, unsigned int dpitch, page = new_page; vaddr = kmap_local_page_try_from_panic(pages[page]); } - if (vaddr) + if (!vaddr) + continue; + + // Special case for 24bit, as a pixel might cross page boundaries + if (cpp == 3 && offset + 3 > PAGE_SIZE) + drm_panic_write_pixel24_xpage(vaddr, pages[page + 1], + offset, fg32); + else drm_panic_write_pixel(vaddr, offset, fg32, cpp); } } @@ -321,7 +355,15 @@ static void drm_panic_fill_page(struct page **pages, unsigned int dpitch, page = new_page; vaddr = kmap_local_page_try_from_panic(pages[page]); } - drm_panic_write_pixel(vaddr, offset, color, cpp); + if (!vaddr) + continue; + + // Special case for 24bit, as a pixel might cross page boundaries + if (cpp == 3 && offset + 3 > PAGE_SIZE) + drm_panic_write_pixel24_xpage(vaddr, pages[page + 1], + offset, color); + else + drm_panic_write_pixel(vaddr, offset, color, cpp); } } if (vaddr)
linux-stable-mirror@lists.linaro.org
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Jocelyn Falempe -
kernel test robot