From: Tingwei Zhang <tingwei@codeaurora.org>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mike Leach <mike.leach@linaro.org>
Cc: tsoni@codeaurora.org,
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
coresight@lists.linaro.org, Mao Jinlong <jinlmao@codeaurora.org>,
linux-kernel@vger.kernel.org,
Tingwei Zhang <tingwei@codeaurora.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] coresight: cti: write regsiters directly in cti_enable_hw()
Date: Tue, 18 Aug 2020 19:10:57 +0800 [thread overview]
Message-ID: <20200818111057.19755-3-tingwei@codeaurora.org> (raw)
In-Reply-To: <20200818111057.19755-1-tingwei@codeaurora.org>
Deadlock as below is triggered by one CPU holds drvdata->spinlock
and calls cti_enable_hw(). Smp_call_function_single() is called
in cti_enable_hw() and tries to let another CPU write CTI registers.
That CPU is trying to get drvdata->spinlock in cti_cpu_pm_notify()
and doesn't response to IPI from smp_call_function_single().
[ 988.335937] CPU: 6 PID: 10258 Comm: sh Tainted: G W L
5.8.0-rc6-mainline-16783-gc38daa79b26b-dirty #1
[ 988.346364] Hardware name: Thundercomm Dragonboard 845c (DT)
[ 988.352073] pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--)
[ 988.357689] pc : smp_call_function_single+0x158/0x1b8
[ 988.362782] lr : smp_call_function_single+0x124/0x1b8
...
[ 988.451638] Call trace:
[ 988.454119] smp_call_function_single+0x158/0x1b8
[ 988.458866] cti_enable+0xb4/0xf8 [coresight_cti]
[ 988.463618] coresight_control_assoc_ectdev+0x6c/0x128 [coresight]
[ 988.469855] coresight_enable+0x1f0/0x364 [coresight]
[ 988.474957] enable_source_store+0x5c/0x9c [coresight]
[ 988.480140] dev_attr_store+0x14/0x28
[ 988.483839] sysfs_kf_write+0x38/0x4c
[ 988.487532] kernfs_fop_write+0x1c0/0x2b0
[ 988.491585] vfs_write+0xfc/0x300
[ 988.494931] ksys_write+0x78/0xe0
[ 988.498283] __arm64_sys_write+0x18/0x20
[ 988.502240] el0_svc_common+0x98/0x160
[ 988.506024] do_el0_svc+0x78/0x80
[ 988.509377] el0_sync_handler+0xd4/0x270
[ 988.513337] el0_sync+0x164/0x180
This change write CTI registers directly in cti_enable_hw().
Config->hw_powered has been checked to be true with spinlock holded.
CTI is powered and can be programmed until spinlock is released.
Fixes: 6a0953ce7de9 ("coresight: cti: Add CPU idle pm notifer to CTI devices")
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
---
drivers/hwtracing/coresight/coresight-cti.c | 17 +----------------
1 file changed, 1 insertion(+), 16 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index 3ccc703dc940..869569eb8c7f 100644
--- a/drivers/hwtracing/coresight/coresight-cti.c
+++ b/drivers/hwtracing/coresight/coresight-cti.c
@@ -86,13 +86,6 @@ void cti_write_all_hw_regs(struct cti_drvdata *drvdata)
CS_LOCK(drvdata->base);
}
-static void cti_enable_hw_smp_call(void *info)
-{
- struct cti_drvdata *drvdata = info;
-
- cti_write_all_hw_regs(drvdata);
-}
-
/* write regs to hardware and enable */
static int cti_enable_hw(struct cti_drvdata *drvdata)
{
@@ -112,15 +105,7 @@ static int cti_enable_hw(struct cti_drvdata *drvdata)
if (rc)
goto cti_err_not_enabled;
- if (drvdata->ctidev.cpu >= 0) {
- rc = smp_call_function_single(drvdata->ctidev.cpu,
- cti_enable_hw_smp_call,
- drvdata, 1);
- if (rc)
- goto cti_err_not_enabled;
- } else {
- cti_write_all_hw_regs(drvdata);
- }
+ cti_write_all_hw_regs(drvdata);
config->hw_enabled = true;
atomic_inc(&drvdata->config.enable_req_count);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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next prev parent reply other threads:[~2020-08-18 11:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-18 11:10 [PATCH] coresight: cti: disclaim device only when it's claimed Tingwei Zhang
2020-08-18 11:10 ` [PATCH] coresight: cti: remove pm_runtime_get_sync() from CPU hotplug Tingwei Zhang
2020-08-18 12:47 ` Mike Leach
2020-08-18 11:10 ` Tingwei Zhang [this message]
2020-08-20 8:06 ` [PATCH] coresight: cti: write regsiters directly in cti_enable_hw() Mike Leach
2020-08-27 18:12 ` Mathieu Poirier
2020-08-28 3:18 ` Tingwei Zhang
2020-08-31 20:28 ` Mathieu Poirier
2020-09-01 6:35 ` Tingwei Zhang
2020-08-27 19:17 ` Mathieu Poirier
2020-08-20 8:12 ` [PATCH] coresight: cti: disclaim device only when it's claimed Mike Leach
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