This is a note to let you know that I've just added the patch titled
coresight: trbe: Fix TRBE potential sleep in atomic context
to the 6.4-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:
coresight-trbe-fix-trbe-potential-sleep-in-atomic-co.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 008fd7a855d86ebc0d50df577d9b6be299c26a98
Author: Junhao He <hejunhao3@xxxxxxxxxx>
Date: Fri Aug 18 16:40:52 2023 +0800
coresight: trbe: Fix TRBE potential sleep in atomic context
[ Upstream commit c0a232f1e19e378c5c4e5973a996392942c80090 ]
smp_call_function_single() will allocate an IPI interrupt vector to
the target processor and send a function call request to the interrupt
vector. After the target processor receives the IPI interrupt, it will
execute arm_trbe_remove_coresight_cpu() call request in the interrupt
handler.
According to the device_unregister() stack information, if other process
is useing the device, the down_write() may sleep, and trigger deadlocks
or unexpected errors.
arm_trbe_remove_coresight_cpu
coresight_unregister
device_unregister
device_del
kobject_del
__kobject_del
sysfs_remove_dir
kernfs_remove
down_write ---------> it may sleep
Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
per TRBE.
Simply call arm_trbe_remove_coresight_cpu() directly without useing the
smp_call_function_single(), which is the same as registering the TRBE
coresight device.
Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Signed-off-by: Junhao He <hejunhao3@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230814093813.19152-2-hejunhao3@xxxxxxxxxx
[ Remove duplicate cpumask checks during removal ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
[ v3 - Remove the operation of assigning NULL to cpudata->drvdata ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Link: https://lore.kernel.org/r/20230818084052.10116-1-hejunhao3@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 1fc4fd79a1c69..925f6c9cecff4 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1223,6 +1223,16 @@ static void arm_trbe_enable_cpu(void *info)
enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
}
+static void arm_trbe_disable_cpu(void *info)
+{
+ struct trbe_drvdata *drvdata = info;
+ struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
+
+ disable_percpu_irq(drvdata->irq);
+ trbe_reset_local(cpudata);
+}
+
+
static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
{
struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
@@ -1324,18 +1334,12 @@ static void arm_trbe_probe_cpu(void *info)
cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
}
-static void arm_trbe_remove_coresight_cpu(void *info)
+static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
{
- int cpu = smp_processor_id();
- struct trbe_drvdata *drvdata = info;
- struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
- disable_percpu_irq(drvdata->irq);
- trbe_reset_local(cpudata);
if (trbe_csdev) {
coresight_unregister(trbe_csdev);
- cpudata->drvdata = NULL;
coresight_set_percpu_sink(cpu, NULL);
}
}
@@ -1364,8 +1368,10 @@ static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
{
int cpu;
- for_each_cpu(cpu, &drvdata->supported_cpus)
- smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1);
+ for_each_cpu(cpu, &drvdata->supported_cpus) {
+ smp_call_function_single(cpu, arm_trbe_disable_cpu, drvdata, 1);
+ arm_trbe_remove_coresight_cpu(drvdata, cpu);
+ }
free_percpu(drvdata->cpudata);
return 0;
}
@@ -1404,12 +1410,8 @@ static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
{
struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
- if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
- struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
-
- disable_percpu_irq(drvdata->irq);
- trbe_reset_local(cpudata);
- }
+ if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+ arm_trbe_disable_cpu(drvdata);
return 0;
}
