This is a note to let you know that I've just added the patch titled
drm/amd/display: use proper context for logging
to the 6.18-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-amd-display-use-proper-context-for-logging.patch
and it can be found in the queue-6.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 114b42507b6a23d9d24e24e4ef165233332c64d4 Mon Sep 17 00:00:00 2001
From: "Jiri Slaby (SUSE)" <[email protected]>
Date: Thu, 23 Jul 2026 06:25:48 +0200
Subject: drm/amd/display: use proper context for logging
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From: Jiri Slaby (SUSE) <[email protected]>
commit 114b42507b6a23d9d24e24e4ef165233332c64d4 upstream.
The same as the rest of the code, get_ss_info_from_atombios() uses
calc_pll_cs->ctx->logger for logging. But calc_pll_cs->ctx is
initialized only later in calc_pll_max_vco_construct(). Therefore, any
output using DC_LOG_SYNC() leads to a NULL pointer deference in
get_ss_info_from_atombios().
According to Sashiko, the very same problem exists in
dce112_get_pix_clk_dividers() and dcn3_get_pix_clk_dividers() too.
To avoid accessing the NULL context, use clk_src->base.ctx->logger
everywhere. That context in base is initialized earlier in
dce110_clk_src_construct() and dce112_clk_src_construct(). Before
get_ss_info_from_atombios() or Sashiko's get_pix_clk_dividers functions
above are actually called. This is done by redefining DC_LOGGER to
CTX->logger.
Before:
dce110_clk_src_construct() did:
-> sets clk_src->base.ctx = ctx;
-> ss_info_from_atombios_create()
-> get_ss_info_from_atombios() <- uses calc_pll_cs->ctx # BOOM
-> calc_pll_max_vco_construct() <- sets calc_pll_cs->ctx
After:
dce110_clk_src_construct() does:
-> sets clk_src->base.ctx = ctx;
-> ss_info_from_atombios_create()
-> get_ss_info_from_atombios() <- uses clk_src->base.ctx
Closes: https://bugzilla.suse.com/show_bug.cgi?id=1271175
Closes:
https://lore.kernel.org/all/[email protected]/
Fixes: 1296423bf23c ("drm/amd/display: define DC_LOGGER for logger")
Reviewed-by: Bhawanpreet Lakha <[email protected]>
Signed-off-by: Jiri Slaby (SUSE) <[email protected]>
Cc: Lakha, Bhawanpreet <[email protected]>
Cc: Harry Wentland <[email protected]>
Cc: Leo Li <[email protected]>
Cc: Rodrigo Siqueira <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "Christian König" <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Simona Vetter <[email protected]>
Cc: [email protected]
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit 6f16fcbb0c46a87e3d9685407e906573d60104b0)
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c | 20 ++++++++----------
1 file changed, 9 insertions(+), 11 deletions(-)
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
@@ -45,9 +45,7 @@
clk_src->base.ctx
#define DC_LOGGER \
- calc_pll_cs->ctx->logger
-#define DC_LOGGER_INIT() \
- struct calc_pll_clock_source *calc_pll_cs = &clk_src->calc_pll
+ CTX->logger
#undef FN
#define FN(reg_name, field_name) \
@@ -291,6 +289,7 @@ static bool calc_pll_dividers_in_range(
}
static uint32_t calculate_pixel_clock_pll_dividers(
+ struct dce110_clk_src *clk_src,
struct calc_pll_clock_source *calc_pll_cs,
struct pll_settings *pll_settings)
{
@@ -479,7 +478,7 @@ static uint32_t dce110_get_pix_clk_divid
{
uint32_t field = 0;
uint32_t pll_calc_error = MAX_PLL_CALC_ERROR;
- DC_LOGGER_INIT();
+
/* Check if reference clock is external (not pcie/xtalin)
* HW Dce80 spec:
* 00 - PCIE_REFCLK, 01 - XTALIN, 02 - GENERICA, 03 - GENERICB
@@ -522,12 +521,14 @@ static uint32_t dce110_get_pix_clk_divid
/*Calculate Dividers by HDMI object, no SS case or SS case */
pll_calc_error =
calculate_pixel_clock_pll_dividers(
+ clk_src,
&clk_src->calc_pll_hdmi,
pll_settings);
else
/*Calculate Dividers by default object, no SS case or SS case */
pll_calc_error =
calculate_pixel_clock_pll_dividers(
+ clk_src,
&clk_src->calc_pll,
pll_settings);
@@ -572,7 +573,6 @@ static uint32_t dce110_get_pix_clk_divid
{
struct dce110_clk_src *clk_src = TO_DCE110_CLK_SRC(cs);
uint32_t pll_calc_error = MAX_PLL_CALC_ERROR;
- DC_LOGGER_INIT();
if (pix_clk_params == NULL || pll_settings == NULL
|| pix_clk_params->requested_pix_clk_100hz == 0) {
@@ -604,7 +604,6 @@ static uint32_t dce112_get_pix_clk_divid
struct pll_settings *pll_settings)
{
struct dce110_clk_src *clk_src = TO_DCE110_CLK_SRC(cs);
- DC_LOGGER_INIT();
if (pix_clk_params == NULL || pll_settings == NULL
|| pix_clk_params->requested_pix_clk_100hz == 0) {
@@ -1370,8 +1369,6 @@ static uint32_t dcn3_get_pix_clk_divider
unsigned long long actual_pix_clk_100Hz = pix_clk_params ?
pix_clk_params->requested_pix_clk_100hz : 0;
struct dce110_clk_src *clk_src = TO_DCE110_CLK_SRC(cs);
- DC_LOGGER_INIT();
-
if (pix_clk_params == NULL || pll_settings == NULL
|| pix_clk_params->requested_pix_clk_100hz == 0) {
DC_LOG_ERROR(
@@ -1441,7 +1438,6 @@ static const struct clock_source_funcs d
.get_pixel_clk_frequency_100hz = get_pixel_clk_frequency_100hz
};
-
static void get_ss_info_from_atombios(
struct dce110_clk_src *clk_src,
enum as_signal_type as_signal,
@@ -1454,7 +1450,7 @@ static void get_ss_info_from_atombios(
struct spread_spectrum_info *ss_info_cur;
struct spread_spectrum_data *ss_data_cur;
uint32_t i;
- DC_LOGGER_INIT();
+
if (ss_entries_num == NULL) {
DC_LOG_SYNC(
"Invalid entry !!!\n");
@@ -1589,6 +1585,7 @@ static void ss_info_from_atombios_create
}
static bool calc_pll_max_vco_construct(
+ struct dce110_clk_src *clk_src,
struct calc_pll_clock_source *calc_pll_cs,
struct calc_pll_clock_source_init_data *init_data)
{
@@ -1740,6 +1737,7 @@ bool dce110_clk_src_construct(
ss_info_from_atombios_create(clk_src);
if (!calc_pll_max_vco_construct(
+ clk_src,
&clk_src->calc_pll,
&calc_pll_cs_init_data)) {
ASSERT_CRITICAL(false);
@@ -1754,7 +1752,7 @@ bool dce110_clk_src_construct(
if (!calc_pll_max_vco_construct(
- &clk_src->calc_pll_hdmi, &calc_pll_cs_init_data_hdmi)) {
+ clk_src, &clk_src->calc_pll_hdmi,
&calc_pll_cs_init_data_hdmi)) {
ASSERT_CRITICAL(false);
goto unexpected_failure;
}
Patches currently in stable-queue which might be from [email protected] are
queue-6.18/drm-amd-display-use-proper-context-for-logging.patch
