From: Kajol Jain <kjain@xxxxxxxxxxxxx>
commit 76d588dddc459fefa1da96e0a081a397c5c8e216 upstream.
Current imc-pmu code triggers a WARNING with CONFIG_DEBUG_ATOMIC_SLEEP
and CONFIG_PROVE_LOCKING enabled, while running a thread_imc event.
Command to trigger the warning:
# perf stat -e thread_imc/CPM_CS_FROM_L4_MEM_X_DPTEG/ sleep 5
Performance counter stats for 'sleep 5':
0 thread_imc/CPM_CS_FROM_L4_MEM_X_DPTEG/
5.002117947 seconds time elapsed
0.000131000 seconds user
0.001063000 seconds sys
Below is snippet of the warning in dmesg:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 2869, name: perf-exec
preempt_count: 2, expected: 0
4 locks held by perf-exec/2869:
#0: c00000004325c540 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: bprm_execve+0x64/0xa90
#1: c00000004325c5d8 (&sig->exec_update_lock){++++}-{3:3}, at: begin_new_exec+0x460/0xef0
#2: c0000003fa99d4e0 (&cpuctx_lock){-...}-{2:2}, at: perf_event_exec+0x290/0x510
#3: c000000017ab8418 (&ctx->lock){....}-{2:2}, at: perf_event_exec+0x29c/0x510
irq event stamp: 4806
hardirqs last enabled at (4805): [<c000000000f65b94>] _raw_spin_unlock_irqrestore+0x94/0xd0
hardirqs last disabled at (4806): [<c0000000003fae44>] perf_event_exec+0x394/0x510
softirqs last enabled at (0): [<c00000000013c404>] copy_process+0xc34/0x1ff0
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 36 PID: 2869 Comm: perf-exec Not tainted 6.2.0-rc2-00011-g1247637727f2 #61
Hardware name: 8375-42A POWER9 0x4e1202 opal:v7.0-16-g9b85f7d961 PowerNV
Call Trace:
dump_stack_lvl+0x98/0xe0 (unreliable)
__might_resched+0x2f8/0x310
__mutex_lock+0x6c/0x13f0
thread_imc_event_add+0xf4/0x1b0
event_sched_in+0xe0/0x210
merge_sched_in+0x1f0/0x600
visit_groups_merge.isra.92.constprop.166+0x2bc/0x6c0
ctx_flexible_sched_in+0xcc/0x140
ctx_sched_in+0x20c/0x2a0
ctx_resched+0x104/0x1c0
perf_event_exec+0x340/0x510
begin_new_exec+0x730/0xef0
load_elf_binary+0x3f8/0x1e10
...
do not call blocking ops when !TASK_RUNNING; state=2001 set at [<00000000fd63e7cf>] do_nanosleep+0x60/0x1a0
WARNING: CPU: 36 PID: 2869 at kernel/sched/core.c:9912 __might_sleep+0x9c/0xb0
CPU: 36 PID: 2869 Comm: sleep Tainted: G W 6.2.0-rc2-00011-g1247637727f2 #61
Hardware name: 8375-42A POWER9 0x4e1202 opal:v7.0-16-g9b85f7d961 PowerNV
NIP: c000000000194a1c LR: c000000000194a18 CTR: c000000000a78670
REGS: c00000004d2134e0 TRAP: 0700 Tainted: G W (6.2.0-rc2-00011-g1247637727f2)
MSR: 9000000000021033 <SF,HV,ME,IR,DR,RI,LE> CR: 48002824 XER: 00000000
CFAR: c00000000013fb64 IRQMASK: 1
The above warning triggered because the current imc-pmu code uses mutex
lock in interrupt disabled sections. The function mutex_lock()
internally calls __might_resched(), which will check if IRQs are
disabled and in case IRQs are disabled, it will trigger the warning.
Fix the issue by changing the mutex lock to spinlock.
Fixes: 8f95faaac56c ("powerpc/powernv: Detect and create IMC device")
Reported-by: Michael Petlan <mpetlan@xxxxxxxxxx>
Reported-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Kajol Jain <kjain@xxxxxxxxxxxxx>
[mpe: Fix comments, trim oops in change log, add reported-by tags]
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230106065157.182648-1-kjain@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/imc-pmu.h | 2
arch/powerpc/perf/imc-pmu.c | 136 +++++++++++++++++--------------------
2 files changed, 67 insertions(+), 71 deletions(-)
--- a/arch/powerpc/include/asm/imc-pmu.h
+++ b/arch/powerpc/include/asm/imc-pmu.h
@@ -132,7 +132,7 @@ struct imc_pmu {
* are inited.
*/
struct imc_pmu_ref {
- struct mutex lock;
+ spinlock_t lock;
unsigned int id;
int refc;
};
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -13,6 +13,7 @@
#include <asm/cputhreads.h>
#include <asm/smp.h>
#include <linux/string.h>
+#include <linux/spinlock.h>
/* Nest IMC data structures and variables */
@@ -20,7 +21,7 @@
* Used to avoid races in counting the nest-pmu units during hotplug
* register and unregister
*/
-static DEFINE_MUTEX(nest_init_lock);
+static DEFINE_SPINLOCK(nest_init_lock);
static DEFINE_PER_CPU(struct imc_pmu_ref *, local_nest_imc_refc);
static struct imc_pmu **per_nest_pmu_arr;
static cpumask_t nest_imc_cpumask;
@@ -49,7 +50,7 @@ static int trace_imc_mem_size;
* core and trace-imc
*/
static struct imc_pmu_ref imc_global_refc = {
- .lock = __MUTEX_INITIALIZER(imc_global_refc.lock),
+ .lock = __SPIN_LOCK_INITIALIZER(imc_global_refc.lock),
.id = 0,
.refc = 0,
};
@@ -393,7 +394,7 @@ static int ppc_nest_imc_cpu_offline(unsi
get_hard_smp_processor_id(cpu));
/*
* If this is the last cpu in this chip then, skip the reference
- * count mutex lock and make the reference count on this chip zero.
+ * count lock and make the reference count on this chip zero.
*/
ref = get_nest_pmu_ref(cpu);
if (!ref)
@@ -455,15 +456,15 @@ static void nest_imc_counters_release(st
/*
* See if we need to disable the nest PMU.
* If no events are currently in use, then we have to take a
- * mutex to ensure that we don't race with another task doing
+ * lock to ensure that we don't race with another task doing
* enable or disable the nest counters.
*/
ref = get_nest_pmu_ref(event->cpu);
if (!ref)
return;
- /* Take the mutex lock for this node and then decrement the reference count */
- mutex_lock(&ref->lock);
+ /* Take the lock for this node and then decrement the reference count */
+ spin_lock(&ref->lock);
if (ref->refc == 0) {
/*
* The scenario where this is true is, when perf session is
@@ -475,7 +476,7 @@ static void nest_imc_counters_release(st
* an OPAL call to disable the engine in that node.
*
*/
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
return;
}
ref->refc--;
@@ -483,7 +484,7 @@ static void nest_imc_counters_release(st
rc = opal_imc_counters_stop(OPAL_IMC_COUNTERS_NEST,
get_hard_smp_processor_id(event->cpu));
if (rc) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("nest-imc: Unable to stop the counters for core %d\n", node_id);
return;
}
@@ -491,7 +492,7 @@ static void nest_imc_counters_release(st
WARN(1, "nest-imc: Invalid event reference count\n");
ref->refc = 0;
}
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
}
static int nest_imc_event_init(struct perf_event *event)
@@ -550,26 +551,25 @@ static int nest_imc_event_init(struct pe
/*
* Get the imc_pmu_ref struct for this node.
- * Take the mutex lock and then increment the count of nest pmu events
- * inited.
+ * Take the lock and then increment the count of nest pmu events inited.
*/
ref = get_nest_pmu_ref(event->cpu);
if (!ref)
return -EINVAL;
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
if (ref->refc == 0) {
rc = opal_imc_counters_start(OPAL_IMC_COUNTERS_NEST,
get_hard_smp_processor_id(event->cpu));
if (rc) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("nest-imc: Unable to start the counters for node %d\n",
node_id);
return rc;
}
}
++ref->refc;
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
event->destroy = nest_imc_counters_release;
return 0;
@@ -605,9 +605,8 @@ static int core_imc_mem_init(int cpu, in
return -ENOMEM;
mem_info->vbase = page_address(page);
- /* Init the mutex */
core_imc_refc[core_id].id = core_id;
- mutex_init(&core_imc_refc[core_id].lock);
+ spin_lock_init(&core_imc_refc[core_id].lock);
rc = opal_imc_counters_init(OPAL_IMC_COUNTERS_CORE,
__pa((void *)mem_info->vbase),
@@ -696,9 +695,8 @@ static int ppc_core_imc_cpu_offline(unsi
perf_pmu_migrate_context(&core_imc_pmu->pmu, cpu, ncpu);
} else {
/*
- * If this is the last cpu in this core then, skip taking refernce
- * count mutex lock for this core and directly zero "refc" for
- * this core.
+ * If this is the last cpu in this core then skip taking reference
+ * count lock for this core and directly zero "refc" for this core.
*/
opal_imc_counters_stop(OPAL_IMC_COUNTERS_CORE,
get_hard_smp_processor_id(cpu));
@@ -713,11 +711,11 @@ static int ppc_core_imc_cpu_offline(unsi
* last cpu in this core and core-imc event running
* in this cpu.
*/
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
if (imc_global_refc.id == IMC_DOMAIN_CORE)
imc_global_refc.refc--;
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
}
return 0;
}
@@ -732,7 +730,7 @@ static int core_imc_pmu_cpumask_init(voi
static void reset_global_refc(struct perf_event *event)
{
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
imc_global_refc.refc--;
/*
@@ -744,7 +742,7 @@ static void reset_global_refc(struct per
imc_global_refc.refc = 0;
imc_global_refc.id = 0;
}
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
}
static void core_imc_counters_release(struct perf_event *event)
@@ -757,17 +755,17 @@ static void core_imc_counters_release(st
/*
* See if we need to disable the IMC PMU.
* If no events are currently in use, then we have to take a
- * mutex to ensure that we don't race with another task doing
+ * lock to ensure that we don't race with another task doing
* enable or disable the core counters.
*/
core_id = event->cpu / threads_per_core;
- /* Take the mutex lock and decrement the refernce count for this core */
+ /* Take the lock and decrement the refernce count for this core */
ref = &core_imc_refc[core_id];
if (!ref)
return;
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
if (ref->refc == 0) {
/*
* The scenario where this is true is, when perf session is
@@ -779,7 +777,7 @@ static void core_imc_counters_release(st
* an OPAL call to disable the engine in that core.
*
*/
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
return;
}
ref->refc--;
@@ -787,7 +785,7 @@ static void core_imc_counters_release(st
rc = opal_imc_counters_stop(OPAL_IMC_COUNTERS_CORE,
get_hard_smp_processor_id(event->cpu));
if (rc) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("IMC: Unable to stop the counters for core %d\n", core_id);
return;
}
@@ -795,7 +793,7 @@ static void core_imc_counters_release(st
WARN(1, "core-imc: Invalid event reference count\n");
ref->refc = 0;
}
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
reset_global_refc(event);
}
@@ -833,7 +831,6 @@ static int core_imc_event_init(struct pe
if ((!pcmi->vbase))
return -ENODEV;
- /* Get the core_imc mutex for this core */
ref = &core_imc_refc[core_id];
if (!ref)
return -EINVAL;
@@ -841,22 +838,22 @@ static int core_imc_event_init(struct pe
/*
* Core pmu units are enabled only when it is used.
* See if this is triggered for the first time.
- * If yes, take the mutex lock and enable the core counters.
+ * If yes, take the lock and enable the core counters.
* If not, just increment the count in core_imc_refc struct.
*/
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
if (ref->refc == 0) {
rc = opal_imc_counters_start(OPAL_IMC_COUNTERS_CORE,
get_hard_smp_processor_id(event->cpu));
if (rc) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("core-imc: Unable to start the counters for core %d\n",
core_id);
return rc;
}
}
++ref->refc;
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
/*
* Since the system can run either in accumulation or trace-mode
@@ -867,7 +864,7 @@ static int core_imc_event_init(struct pe
* to know whether any other trace/thread imc
* events are running.
*/
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
if (imc_global_refc.id == 0 || imc_global_refc.id == IMC_DOMAIN_CORE) {
/*
* No other trace/thread imc events are running in
@@ -876,10 +873,10 @@ static int core_imc_event_init(struct pe
imc_global_refc.id = IMC_DOMAIN_CORE;
imc_global_refc.refc++;
} else {
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
return -EBUSY;
}
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
event->hw.event_base = (u64)pcmi->vbase + (config & IMC_EVENT_OFFSET_MASK);
event->destroy = core_imc_counters_release;
@@ -951,10 +948,10 @@ static int ppc_thread_imc_cpu_offline(un
mtspr(SPRN_LDBAR, (mfspr(SPRN_LDBAR) & (~(1UL << 63))));
/* Reduce the refc if thread-imc event running on this cpu */
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
if (imc_global_refc.id == IMC_DOMAIN_THREAD)
imc_global_refc.refc--;
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
return 0;
}
@@ -994,7 +991,7 @@ static int thread_imc_event_init(struct
if (!target)
return -EINVAL;
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
/*
* Check if any other trace/core imc events are running in the
* system, if not set the global id to thread-imc.
@@ -1003,10 +1000,10 @@ static int thread_imc_event_init(struct
imc_global_refc.id = IMC_DOMAIN_THREAD;
imc_global_refc.refc++;
} else {
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
return -EBUSY;
}
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
event->pmu->task_ctx_nr = perf_sw_context;
event->destroy = reset_global_refc;
@@ -1128,25 +1125,25 @@ static int thread_imc_event_add(struct p
/*
* imc pmus are enabled only when it is used.
* See if this is triggered for the first time.
- * If yes, take the mutex lock and enable the counters.
+ * If yes, take the lock and enable the counters.
* If not, just increment the count in ref count struct.
*/
ref = &core_imc_refc[core_id];
if (!ref)
return -EINVAL;
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
if (ref->refc == 0) {
if (opal_imc_counters_start(OPAL_IMC_COUNTERS_CORE,
get_hard_smp_processor_id(smp_processor_id()))) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("thread-imc: Unable to start the counter\
for core %d\n", core_id);
return -EINVAL;
}
}
++ref->refc;
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
return 0;
}
@@ -1163,12 +1160,12 @@ static void thread_imc_event_del(struct
return;
}
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
ref->refc--;
if (ref->refc == 0) {
if (opal_imc_counters_stop(OPAL_IMC_COUNTERS_CORE,
get_hard_smp_processor_id(smp_processor_id()))) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("thread-imc: Unable to stop the counters\
for core %d\n", core_id);
return;
@@ -1176,7 +1173,7 @@ static void thread_imc_event_del(struct
} else if (ref->refc < 0) {
ref->refc = 0;
}
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
/* Set bit 0 of LDBAR to zero, to stop posting updates to memory */
mtspr(SPRN_LDBAR, (mfspr(SPRN_LDBAR) & (~(1UL << 63))));
@@ -1217,9 +1214,8 @@ static int trace_imc_mem_alloc(int cpu_i
}
}
- /* Init the mutex, if not already */
trace_imc_refc[core_id].id = core_id;
- mutex_init(&trace_imc_refc[core_id].lock);
+ spin_lock_init(&trace_imc_refc[core_id].lock);
mtspr(SPRN_LDBAR, 0);
return 0;
@@ -1239,10 +1235,10 @@ static int ppc_trace_imc_cpu_offline(uns
* Reduce the refc if any trace-imc event running
* on this cpu.
*/
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
if (imc_global_refc.id == IMC_DOMAIN_TRACE)
imc_global_refc.refc--;
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
return 0;
}
@@ -1345,17 +1341,17 @@ static int trace_imc_event_add(struct pe
}
mtspr(SPRN_LDBAR, ldbar_value);
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
if (ref->refc == 0) {
if (opal_imc_counters_start(OPAL_IMC_COUNTERS_TRACE,
get_hard_smp_processor_id(smp_processor_id()))) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("trace-imc: Unable to start the counters for core %d\n", core_id);
return -EINVAL;
}
}
++ref->refc;
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
return 0;
}
@@ -1388,19 +1384,19 @@ static void trace_imc_event_del(struct p
return;
}
- mutex_lock(&ref->lock);
+ spin_lock(&ref->lock);
ref->refc--;
if (ref->refc == 0) {
if (opal_imc_counters_stop(OPAL_IMC_COUNTERS_TRACE,
get_hard_smp_processor_id(smp_processor_id()))) {
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
pr_err("trace-imc: Unable to stop the counters for core %d\n", core_id);
return;
}
} else if (ref->refc < 0) {
ref->refc = 0;
}
- mutex_unlock(&ref->lock);
+ spin_unlock(&ref->lock);
trace_imc_event_stop(event, flags);
}
@@ -1424,7 +1420,7 @@ static int trace_imc_event_init(struct p
* no other thread is running any core/thread imc
* events
*/
- mutex_lock(&imc_global_refc.lock);
+ spin_lock(&imc_global_refc.lock);
if (imc_global_refc.id == 0 || imc_global_refc.id == IMC_DOMAIN_TRACE) {
/*
* No core/thread imc events are running in the
@@ -1433,10 +1429,10 @@ static int trace_imc_event_init(struct p
imc_global_refc.id = IMC_DOMAIN_TRACE;
imc_global_refc.refc++;
} else {
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
return -EBUSY;
}
- mutex_unlock(&imc_global_refc.lock);
+ spin_unlock(&imc_global_refc.lock);
event->hw.idx = -1;
target = event->hw.target;
@@ -1509,10 +1505,10 @@ static int init_nest_pmu_ref(void)
i = 0;
for_each_node(nid) {
/*
- * Mutex lock to avoid races while tracking the number of
+ * Take the lock to avoid races while tracking the number of
* sessions using the chip's nest pmu units.
*/
- mutex_init(&nest_imc_refc[i].lock);
+ spin_lock_init(&nest_imc_refc[i].lock);
/*
* Loop to init the "id" with the node_id. Variable "i" initialized to
@@ -1609,7 +1605,7 @@ static void imc_common_mem_free(struct i
static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
{
if (pmu_ptr->domain == IMC_DOMAIN_NEST) {
- mutex_lock(&nest_init_lock);
+ spin_lock(&nest_init_lock);
if (nest_pmus == 1) {
cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
kfree(nest_imc_refc);
@@ -1619,7 +1615,7 @@ static void imc_common_cpuhp_mem_free(st
if (nest_pmus > 0)
nest_pmus--;
- mutex_unlock(&nest_init_lock);
+ spin_unlock(&nest_init_lock);
}
/* Free core_imc memory */
@@ -1776,11 +1772,11 @@ int init_imc_pmu(struct device_node *par
* rest. To handle the cpuhotplug callback unregister, we track
* the number of nest pmus in "nest_pmus".
*/
- mutex_lock(&nest_init_lock);
+ spin_lock(&nest_init_lock);
if (nest_pmus == 0) {
ret = init_nest_pmu_ref();
if (ret) {
- mutex_unlock(&nest_init_lock);
+ spin_unlock(&nest_init_lock);
kfree(per_nest_pmu_arr);
per_nest_pmu_arr = NULL;
goto err_free_mem;
@@ -1788,7 +1784,7 @@ int init_imc_pmu(struct device_node *par
/* Register for cpu hotplug notification. */
ret = nest_pmu_cpumask_init();
if (ret) {
- mutex_unlock(&nest_init_lock);
+ spin_unlock(&nest_init_lock);
kfree(nest_imc_refc);
kfree(per_nest_pmu_arr);
per_nest_pmu_arr = NULL;
@@ -1796,7 +1792,7 @@ int init_imc_pmu(struct device_node *par
}
}
nest_pmus++;
- mutex_unlock(&nest_init_lock);
+ spin_unlock(&nest_init_lock);
break;
case IMC_DOMAIN_CORE:
ret = core_imc_pmu_cpumask_init();
