[PATCH 6.1 0726/1146] coresight: cti: Fix null pointer error on CTI init before ETM

Greg Kroah-Hartman
2022-12-28T16:29:39Z

From: Mike Leach <mike.leach@linaro.org>

[ Upstream commit 3dc228b35387803d9c43ed1b098aabb1d3ae9c7d ]

When CTI is discovered first then the function
coresight_set_assoc_ectdev_mutex() is called to set the association
between CTI and ETM device. Recent lockdep fix passes a null pointer.

This patch passes the correct pointer.

Before patch: log of boot oops sequence with CTI discovered first:

[ 12.424091] cs_system_cfg: CoreSight Configuration manager initialised
[ 12.483474] coresight cti_sys0: CTI initialized
[ 12.488109] coresight cti_sys1: CTI initialized
[ 12.503594] coresight cti_cpu0: CTI initialized
[ 12.517877] coresight-cpu-debug 850000.debug: Coresight debug-CPU0 initialized
[ 12.523479] coresight-cpu-debug 852000.debug: Coresight debug-CPU1 initialized
[ 12.529926] coresight-cpu-debug 854000.debug: Coresight debug-CPU2 initialized
[ 12.541808] coresight stm0: STM32 initialized
[ 12.544421] coresight-cpu-debug 856000.debug: Coresight debug-CPU3 initialized
[ 12.585639] coresight cti_cpu1: CTI initialized
[ 12.614028] coresight cti_cpu2: CTI initialized
[ 12.631679] CSCFG registered etm0
[ 12.633920] coresight etm0: CPU0: etm v4.0 initialized
[ 12.656392] coresight cti_cpu3: CTI initialized

...

[ 12.708383] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000348

...

[ 12.755094] Internal error: Oops: 0000000096000044 [#1] SMP
[ 12.761817] Modules linked in: coresight_etm4x(+) coresight_tmc coresight_cpu_debug coresight_replicator coresight_funnel coresight_cti coresight_tpiu coresight_stm coresight
[ 12.767210] CPU: 3 PID: 1346 Comm: systemd-udevd Not tainted 6.1.0-rc3tid-v6tid-v6-235166-gf7f7d7a2204a-dirty #498
[ 12.782827] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
[ 12.793154] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 12.800010] pc : coresight_set_assoc_ectdev_mutex+0x30/0x50 [coresight]
[ 12.806694] lr : coresight_set_assoc_ectdev_mutex+0x30/0x50 [coresight]

...

[ 12.885064] Call trace:
[ 12.892352] coresight_set_assoc_ectdev_mutex+0x30/0x50 [coresight]
[ 12.894693] cti_add_assoc_to_csdev+0x144/0x1b0 [coresight_cti]
[ 12.900943] coresight_register+0x2c8/0x320 [coresight]
[ 12.906844] etm4_add_coresight_dev.isra.27+0x148/0x280 [coresight_etm4x]
[ 12.912056] etm4_probe+0x144/0x1c0 [coresight_etm4x]
[ 12.918998] etm4_probe_amba+0x40/0x78 [coresight_etm4x]
[ 12.924032] amba_probe+0x11c/0x1f0

After patch: similar log

[ 12.444467] cs_system_cfg: CoreSight Configuration manager initialised
[ 12.456329] coresight-cpu-debug 850000.debug: Coresight debug-CPU0 initialized
[ 12.456754] coresight-cpu-debug 852000.debug: Coresight debug-CPU1 initialized
[ 12.469672] coresight-cpu-debug 854000.debug: Coresight debug-CPU2 initialized
[ 12.476098] coresight-cpu-debug 856000.debug: Coresight debug-CPU3 initialized
[ 12.532409] coresight stm0: STM32 initialized
[ 12.533708] coresight cti_sys0: CTI initialized
[ 12.539478] coresight cti_sys1: CTI initialized
[ 12.550106] coresight cti_cpu0: CTI initialized
[ 12.633931] coresight cti_cpu1: CTI initialized
[ 12.634664] coresight cti_cpu2: CTI initialized
[ 12.638090] coresight cti_cpu3: CTI initialized
[ 12.721136] CSCFG registered etm0

...

[ 12.762643] CSCFG registered etm1
[ 12.762666] coresight etm1: CPU1: etm v4.0 initialized
[ 12.776258] CSCFG registered etm2
[ 12.776282] coresight etm2: CPU2: etm v4.0 initialized
[ 12.784357] CSCFG registered etm3
[ 12.785455] coresight etm3: CPU3: etm v4.0 initialized

Error can also be triggered by manually starting the modules using modprobe
in the following order:

root@linaro-developer:/home/linaro/cs-mods# modprobe coresight
root@linaro-developer:/home/linaro/cs-mods# modprobe coresight-cti
root@linaro-developer:/home/linaro/cs-mods# modprobe coresight-etm4x

Tested on Dragonboard DB410c
Applies to coresight/next

Fixes: 23722fb46725 ("coresight: Fix possible deadlock with lock dependency")
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20221123193818.6253-1-mike.leach@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwtracing/coresight/coresight-cti-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index c6e8c6542f24..d2cf4f4848e1 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -564,7 +564,7 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
* if we found a matching csdev then update the ECT
* association pointer for the device with this CTI.
*/
- coresight_set_assoc_ectdev_mutex(csdev->ect_dev,
+ coresight_set_assoc_ectdev_mutex(csdev,
ect_item->csdev);
break;
}
--
2.35.1