This is a note to let you know that I've just added the patch titled

    drm/meson: Fix OOB memory accesses in meson_viu_set_osd_lut()

to the 4.19-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-meson-fix-oob-memory-accesses-in-meson_viu_set_osd_lut.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.


From 97b2a3180a559a33852ac0cd77904166069484fd Mon Sep 17 00:00:00 2001
From: Lyude Paul <ly...@redhat.com>
Date: Sat, 24 Nov 2018 20:21:17 -0500
Subject: drm/meson: Fix OOB memory accesses in meson_viu_set_osd_lut()

From: Lyude Paul <ly...@redhat.com>

commit 97b2a3180a559a33852ac0cd77904166069484fd upstream.

Currently on driver bringup with KASAN enabled, meson triggers an OOB
memory access as shown below:

[  117.904528] 
==================================================================
[  117.904560] BUG: KASAN: global-out-of-bounds in 
meson_viu_set_osd_lut+0x7a0/0x890
[  117.904588] Read of size 4 at addr ffff20000a63ce24 by task systemd-udevd/498
[  117.904601]
[  118.083372] CPU: 4 PID: 498 Comm: systemd-udevd Not tainted 
4.20.0-rc3Lyude-Test+ #20
[  118.091143] Hardware name: amlogic khadas-vim2/khadas-vim2, BIOS 
2018.07-rc2-armbian 09/11/2018
[  118.099768] Call trace:
[  118.102181]  dump_backtrace+0x0/0x3e8
[  118.105796]  show_stack+0x14/0x20
[  118.109083]  dump_stack+0x130/0x1c4
[  118.112539]  print_address_description+0x60/0x25c
[  118.117214]  kasan_report+0x1b4/0x368
[  118.120851]  __asan_report_load4_noabort+0x18/0x20
[  118.125566]  meson_viu_set_osd_lut+0x7a0/0x890
[  118.129953]  meson_viu_init+0x10c/0x290
[  118.133741]  meson_drv_bind_master+0x474/0x748
[  118.138141]  meson_drv_bind+0x10/0x18
[  118.141760]  try_to_bring_up_master+0x3d8/0x768
[  118.146249]  component_add+0x214/0x570
[  118.149978]  meson_dw_hdmi_probe+0x18/0x20 [meson_dw_hdmi]
[  118.155404]  platform_drv_probe+0x98/0x138
[  118.159455]  really_probe+0x2a0/0xa70
[  118.163070]  driver_probe_device+0x1b4/0x2d8
[  118.167299]  __driver_attach+0x200/0x280
[  118.171189]  bus_for_each_dev+0x10c/0x1a8
[  118.175144]  driver_attach+0x38/0x50
[  118.178681]  bus_add_driver+0x330/0x608
[  118.182471]  driver_register+0x140/0x388
[  118.186361]  __platform_driver_register+0xc8/0x108
[  118.191117]  meson_dw_hdmi_platform_driver_init+0x1c/0x1000 [meson_dw_hdmi]
[  118.198022]  do_one_initcall+0x12c/0x3bc
[  118.201883]  do_init_module+0x1fc/0x638
[  118.205673]  load_module+0x4b4c/0x6808
[  118.209387]  __se_sys_init_module+0x2e8/0x3c0
[  118.213699]  __arm64_sys_init_module+0x68/0x98
[  118.218100]  el0_svc_common+0x104/0x210
[  118.221893]  el0_svc_handler+0x48/0xb8
[  118.225594]  el0_svc+0x8/0xc
[  118.228429]
[  118.229887] The buggy address belongs to the variable:
[  118.235007]  eotf_33_linear_mapping+0x84/0xc0
[  118.239301]
[  118.240752] Memory state around the buggy address:
[  118.245522]  ffff20000a63cd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00
[  118.252695]  ffff20000a63cd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00
[  118.259850] >ffff20000a63ce00: 00 00 00 00 04 fa fa fa fa fa fa fa 00 00 00 
00
[  118.267000]                                ^
[  118.271222]  ffff20000a63ce80: 00 fa fa fa fa fa fa fa 00 00 00 00 00 00 00 
00
[  118.278393]  ffff20000a63cf00: 00 00 00 00 00 00 00 00 00 00 00 00 04 fa fa 
fa
[  118.285542] 
==================================================================
[  118.292699] Disabling lock debugging due to kernel taint

It seems that when looping through the OSD EOTF LUT maps, we use the
same max iterator for OETF: 20. This is wrong though, since 20*2 is 40,
which means that we'll stop out of bounds on the EOTF maps.

But, this whole thing is already confusing enough to read through as-is,
so let's just replace all of the hardcoded sizes with
OSD_(OETF/EOTF)_LUT_SIZE / 2.

Signed-off-by: Lyude Paul <ly...@redhat.com>
Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Cc: Neil Armstrong <narmstr...@baylibre.com>
Cc: Maxime Ripard <maxime.rip...@bootlin.com>
Cc: Carlo Caione <ca...@caione.org>
Cc: Kevin Hilman <khil...@baylibre.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-amlo...@lists.infradead.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: <sta...@vger.kernel.org> # v4.10+
Acked-by: Neil Armstrong <narmstr...@baylibre.com>
Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20181125012117.31915-1-ly...@redhat.com
Signed-off-by: Sean Paul <seanp...@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/gpu/drm/meson/meson_viu.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/meson/meson_viu.c
+++ b/drivers/gpu/drm/meson/meson_viu.c
@@ -184,18 +184,18 @@ void meson_viu_set_osd_lut(struct meson_
        if (lut_sel == VIU_LUT_OSD_OETF) {
                writel(0, priv->io_base + _REG(addr_port));
 
-               for (i = 0; i < 20; i++)
+               for (i = 0; i < (OSD_OETF_LUT_SIZE / 2); i++)
                        writel(r_map[i * 2] | (r_map[i * 2 + 1] << 16),
                                priv->io_base + _REG(data_port));
 
                writel(r_map[OSD_OETF_LUT_SIZE - 1] | (g_map[0] << 16),
                        priv->io_base + _REG(data_port));
 
-               for (i = 0; i < 20; i++)
+               for (i = 0; i < (OSD_OETF_LUT_SIZE / 2); i++)
                        writel(g_map[i * 2 + 1] | (g_map[i * 2 + 2] << 16),
                                priv->io_base + _REG(data_port));
 
-               for (i = 0; i < 20; i++)
+               for (i = 0; i < (OSD_OETF_LUT_SIZE / 2); i++)
                        writel(b_map[i * 2] | (b_map[i * 2 + 1] << 16),
                                priv->io_base + _REG(data_port));
 
@@ -211,18 +211,18 @@ void meson_viu_set_osd_lut(struct meson_
        } else if (lut_sel == VIU_LUT_OSD_EOTF) {
                writel(0, priv->io_base + _REG(addr_port));
 
-               for (i = 0; i < 20; i++)
+               for (i = 0; i < (OSD_EOTF_LUT_SIZE / 2); i++)
                        writel(r_map[i * 2] | (r_map[i * 2 + 1] << 16),
                                priv->io_base + _REG(data_port));
 
                writel(r_map[OSD_EOTF_LUT_SIZE - 1] | (g_map[0] << 16),
                        priv->io_base + _REG(data_port));
 
-               for (i = 0; i < 20; i++)
+               for (i = 0; i < (OSD_EOTF_LUT_SIZE / 2); i++)
                        writel(g_map[i * 2 + 1] | (g_map[i * 2 + 2] << 16),
                                priv->io_base + _REG(data_port));
 
-               for (i = 0; i < 20; i++)
+               for (i = 0; i < (OSD_EOTF_LUT_SIZE / 2); i++)
                        writel(b_map[i * 2] | (b_map[i * 2 + 1] << 16),
                                priv->io_base + _REG(data_port));
 


Patches currently in stable-queue which might be from ly...@redhat.com are

queue-4.19/drm-meson-enable-fast_io-in-meson_dw_hdmi_regmap_config.patch
queue-4.19/drm-amd-dm-understand-why-attaching-path-tile-properties-are-needed.patch
queue-4.19/drm-amd-dm-don-t-forget-to-attach-mst-encoders.patch
queue-4.19/drm-meson-fixes-for-drm_crtc_vblank_on-off-support.patch
queue-4.19/drm-meson-fix-oob-memory-accesses-in-meson_viu_set_osd_lut.patch
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