This is a note to let you know that I've just added the patch titled drm/panfrost: Don't try to map pages that are already mapped to the 5.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-panfrost-don-t-try-to-map-pages-that-are-already-mapped.patch and it can be found in the queue-5.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f45da8204ff1707c529a8769f5467ff16f504b26 Mon Sep 17 00:00:00 2001 From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> Date: Fri, 5 Feb 2021 12:17:56 +0100 Subject: drm/panfrost: Don't try to map pages that are already mapped From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> commit f45da8204ff1707c529a8769f5467ff16f504b26 upstream. We allocate 2MB chunks at a time, so it might appear that a page fault has already been handled by a previous page fault when we reach panfrost_mmu_map_fault_addr(). Bail out in that case to avoid mapping the same area twice. Cc: <stable@xxxxxxxxxxxxxxx> Fixes: 187d2929206e ("drm/panfrost: Add support for GPU heap allocations") Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> Reviewed-by: Steven Price <steven.price@xxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20210205111757.585248-3-boris.brezillon@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/panfrost/panfrost_mmu.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c @@ -488,8 +488,14 @@ static int panfrost_mmu_map_fault_addr(s } bo->base.pages = pages; bo->base.pages_use_count = 1; - } else + } else { pages = bo->base.pages; + if (pages[page_offset]) { + /* Pages are already mapped, bail out. */ + mutex_unlock(&bo->base.pages_lock); + goto out; + } + } mapping = bo->base.base.filp->f_mapping; mapping_set_unevictable(mapping); @@ -522,6 +528,7 @@ static int panfrost_mmu_map_fault_addr(s dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr); +out: panfrost_gem_mapping_put(bomapping); return 0; Patches currently in stable-queue which might be from boris.brezillon@xxxxxxxxxxxxx are queue-5.11/drm-panfrost-don-t-try-to-map-pages-that-are-already-mapped.patch queue-5.11/drm-panfrost-clear-mmu-irqs-before-handling-the-fault.patch