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Y. Srinivasan" , Haiyang Zhang , Dexuan Cui , Helge Deller , linux-hyperv@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH 6.6.y 1/2] fbdev: hyperv_fb: Simplify hvfb_putmem Date: Thu, 8 Oct 2026 15:13:04 -0400 Message-ID: <20261008191309.98263-2-artem@trailofbits.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261008191309.98263-1-artem@trailofbits.com> References: <20261008191309.98263-1-artem@trailofbits.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Saurabh Sengar [ Upstream commit f5e728a50bb17336a20803dde488515b833ecd1d ] The device object required in 'hvfb_release_phymem' function for 'dma_free_coherent' can also be obtained from the 'info' pointer, making 'hdev' parameter in 'hvfb_putmem' redundant. Remove the unnecessary 'hdev' argument from 'hvfb_putmem'. [ Backport to 6.6.y: Pass info->device through the target's hvfb_release_phymem() helper and remove the now-redundant hdev argument from each hvfb_putmem() call. ] Signed-off-by: Saurabh Sengar Reviewed-by: Michael Kelley Tested-by: Michael Kelley Link: https://lore.kernel.org/r/1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com> Assisted-by: LLM Signed-off-by: Artem Dinaburg --- This is patch 1 of 2 in the ordered 6.6.y backport series. This is the prerequisite needed for the CVE-2025-21976 backport. Makes hvfb_putmem() derive the device from fb_info, which permits the following fix to move framebuffer-memory release into fb_destroy() and honor outstanding open references. The fix is already present in 6.12.y, 6.18.y, and 7.2.y, but not in 6.6.y. This fix also affects 6.1.y, which will need a separate backport; this submission contains only the 6.6.y patch. drivers/video/fbdev/hyperv_fb.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c index 80e8ec36b7db..80e6d9682179 100644 --- a/drivers/video/fbdev/hyperv_fb.c +++ b/drivers/video/fbdev/hyperv_fb.c @@ -973,7 +973,7 @@ static phys_addr_t hvfb_get_phymem(struct hv_device *hdev, } /* Release contiguous physical memory */ -static void hvfb_release_phymem(struct hv_device *hdev, +static void hvfb_release_phymem(struct device *device, phys_addr_t paddr, unsigned int size) { unsigned int order = get_order(size); @@ -981,7 +981,7 @@ static void hvfb_release_phymem(struct hv_device *hdev, if (order <= MAX_ORDER) __free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order); else - dma_free_coherent(&hdev->device, + dma_free_coherent(device, round_up(size, PAGE_SIZE), phys_to_virt(paddr), paddr); @@ -1100,7 +1100,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) } /* Release the framebuffer */ -static void hvfb_putmem(struct hv_device *hdev, struct fb_info *info) +static void hvfb_putmem(struct fb_info *info) { struct hvfb_par *par = info->par; @@ -1109,7 +1109,7 @@ static void hvfb_putmem(struct hv_device *hdev, struct fb_info *info) iounmap(par->mmio_vp); vmbus_free_mmio(par->mem->start, screen_fb_size); } else { - hvfb_release_phymem(hdev, info->fix.smem_start, + hvfb_release_phymem(info->device, info->fix.smem_start, screen_fb_size); } @@ -1223,7 +1223,7 @@ static int hvfb_probe(struct hv_device *hdev, error: fb_deferred_io_cleanup(info); - hvfb_putmem(hdev, info); + hvfb_putmem(info); error2: vmbus_close(hdev->channel); error1: @@ -1252,7 +1252,7 @@ static void hvfb_remove(struct hv_device *hdev) vmbus_close(hdev->channel); hv_set_drvdata(hdev, NULL); - hvfb_putmem(hdev, info); + hvfb_putmem(info); framebuffer_release(info); } -- 2.39.5