5.15-stable patches

added patches:
	fbdev-fix-incorrect-address-computation-in-deferred-io.patch

diff --git a/queue-5.15/fbdev-fix-incorrect-address-computation-in-deferred-io.patch b/queue-5.15/fbdev-fix-incorrect-address-computation-in-deferred-io.patch
new file mode 100644 (file)
index 0000000..6428a83
--- /dev/null
+++ b/queue-5.15/fbdev-fix-incorrect-address-computation-in-deferred-io.patch
@@ -0,0 +1,57 @@
+From 78d9161d2bcd442d93d917339297ffa057dbee8c Mon Sep 17 00:00:00 2001
+From: Nam Cao <namcao@linutronix.de>
+Date: Tue, 23 Apr 2024 13:50:53 +0200
+Subject: fbdev: fix incorrect address computation in deferred IO
+
+From: Nam Cao <namcao@linutronix.de>
+
+commit 78d9161d2bcd442d93d917339297ffa057dbee8c upstream.
+
+With deferred IO enabled, a page fault happens when data is written to the
+framebuffer device. Then driver determines which page is being updated by
+calculating the offset of the written virtual address within the virtual
+memory area, and uses this offset to get the updated page within the
+internal buffer. This page is later copied to hardware (thus the name
+"deferred IO").
+
+This offset calculation is only correct if the virtual memory area is
+mapped to the beginning of the internal buffer. Otherwise this is wrong.
+For example, if users do:
+    mmap(ptr, 4096, PROT_WRITE, MAP_FIXED | MAP_SHARED, fd, 0xff000);
+
+Then the virtual memory area will mapped at offset 0xff000 within the
+internal buffer. This offset 0xff000 is not accounted for, and wrong page
+is updated.
+
+Correct the calculation by using vmf->pgoff instead. With this change, the
+variable "offset" will no longer hold the exact offset value, but it is
+rounded down to multiples of PAGE_SIZE. But this is still correct, because
+this variable is only used to calculate the page offset.
+
+Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
+Closes: https://lore.kernel.org/linux-fbdev/271372d6-e665-4e7f-b088-dee5f4ab341a@oracle.com
+Fixes: 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct")
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Nam Cao <namcao@linutronix.de>
+Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
+Tested-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
+Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
+Link: https://patchwork.freedesktop.org/patch/msgid/20240423115053.4490-1-namcao@linutronix.de
+[rebase to v5.15]
+Signed-off-by: Nam Cao <namcao@linutronix.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/video/fbdev/core/fb_defio.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/video/fbdev/core/fb_defio.c
++++ b/drivers/video/fbdev/core/fb_defio.c
+@@ -149,7 +149,7 @@ static vm_fault_t fb_deferred_io_mkwrite
+       unsigned long offset;
+       vm_fault_t ret;
+ 
+-      offset = (vmf->address - vmf->vma->vm_start);
++      offset = vmf->pgoff << PAGE_SHIFT;
+ 
+       /* this is a callback we get when userspace first tries to
+       write to the page. we schedule a workqueue. that workqueue

diff --git a/queue-5.15/series b/queue-5.15/series
index 9bc3f3a334db2b0891c4a8cba7ccb2594837e8e9..65159315497dee5eb22e1afd13ba1687b2acd1c3 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -73,3 +73,4 @@ dmaengine-idxd-fix-oops-during-rmmod-on-single-cpu-p.patch
 riscv-fix-vmalloc_start-definition.patch
 riscv-fix-task_size-on-64-bit-nommu.patch
 i2c-smbus-fix-null-function-pointer-dereference.patch
+fbdev-fix-incorrect-address-computation-in-deferred-io.patch