coresight: Fixes for v5.2-rc5

As requested here is a set to fix problems found up to now in this cycle, supplemented with stable tags where applicable.

Thanks,
Mathieu

Dan Carpenter (1):
coresight: Potential uninitialized variable in probe()

Suzuki K Poulose (4):
coresight: tmc-etr: Do not call smp_processor_id() from preemptible
coresight: tmc-etr: alloc_perf_buf: Do not call smp_processor_id from
preemptible
coresight: tmc-etf: Do not call smp_processor_id from preemptible
coresight: etb10: Do not call smp_processor_id from preemptible

 drivers/hwtracing/coresight/coresight-etb10.c   |  6 ++----
 drivers/hwtracing/coresight/coresight-funnel.c  |  1 +
 drivers/hwtracing/coresight/coresight-tmc-etf.c |  6 ++----
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 13 ++++---------
 4 files changed, 9 insertions(+), 17 deletions(-)

2.17.1


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From: Suzuki K Poulose <[email protected]>

During a perf session we try to allocate buffers on the "node" associated with the CPU the event is bound to. If it's not bound to a CPU, we use the current CPU node, using smp_processor_id(). However this is unsafe in a pre-emptible context and could generate the splats as below :

 BUG: using smp_processor_id() in preemptible [00000000] code: perf/1743
 caller is alloc_etr_buf.isra.6+0x80/0xa0
 CPU: 1 PID: 1743 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344
 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb  1 2019
  Call trace:
   dump_backtrace+0x0/0x150
   show_stack+0x14/0x20
   dump_stack+0x9c/0xc4
   debug_smp_processor_id+0x10c/0x110
   alloc_etr_buf.isra.6+0x80/0xa0
   tmc_alloc_etr_buffer+0x12c/0x1f0
   etm_setup_aux+0x1c4/0x230
   rb_alloc_aux+0x1b8/0x2b8
   perf_mmap+0x35c/0x478
   mmap_region+0x34c/0x4f0
   do_mmap+0x2d8/0x418
   vm_mmap_pgoff+0xd0/0xf8
   ksys_mmap_pgoff+0x88/0xf8
   __arm64_sys_mmap+0x28/0x38
   el0_svc_handler+0xd8/0x138
   el0_svc+0x8/0xc

Use NUMA_NO_NODE hint instead of using the current node for events not bound to CPUs.

---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

index df6e4b0b84e9..c6a36897924f 100644
@@ -1317,13 +1317,11 @@ static struct etr_perf_buffer *
 tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 		       int nr_pages, void **pages, bool snapshot)
 {
-	int node, cpu = event->cpu;
+	int node;
 	struct etr_buf *etr_buf;
 	struct etr_perf_buffer *etr_perf;
 
-	if (cpu == -1)
-		cpu = smp_processor_id();
-	node = cpu_to_node(cpu);
+	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
 
 	etr_perf = kzalloc_node(sizeof(*etr_perf), GFP_KERNEL, node);
 	if (!etr_perf)

2.17.1


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This should be:

Add:

	[core]
	        abbrev = 12

to your .gitconfig file, we only need 12 in the kernel tree. For now :)

thanks,

greg k-h

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From: Suzuki K Poulose <[email protected]>

During a perf session we try to allocate buffers on the "node" associated with the CPU the event is bound to. If it is not bound to a CPU, we use the current CPU node, using smp_processor_id(). However this is unsafe in a pre-emptible context and could generate the splats as below :

 BUG: using smp_processor_id() in preemptible [00000000] code: perf/1743
 caller is tmc_alloc_etr_buffer+0x1bc/0x1f0
 CPU: 1 PID: 1743 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344
 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb  1 2019
 Call trace:
  dump_backtrace+0x0/0x150
  show_stack+0x14/0x20
  dump_stack+0x9c/0xc4
  debug_smp_processor_id+0x10c/0x110
  tmc_alloc_etr_buffer+0x1bc/0x1f0
  etm_setup_aux+0x1c4/0x230
  rb_alloc_aux+0x1b8/0x2b8
  perf_mmap+0x35c/0x478
  mmap_region+0x34c/0x4f0
  do_mmap+0x2d8/0x418
  vm_mmap_pgoff+0xd0/0xf8
  ksys_mmap_pgoff+0x88/0xf8
  __arm64_sys_mmap+0x28/0x38
  el0_svc_handler+0xd8/0x138
  el0_svc+0x8/0xc

Use NUMA_NO_NODE hint instead of using the current node for events not bound to CPUs.

---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

index c6a36897924f..9f293b9dce8c 100644
@@ -1178,14 +1178,11 @@ static struct etr_buf *
 alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 	      int nr_pages, void **pages, bool snapshot)
 {
-	int node, cpu = event->cpu;
+	int node;
 	struct etr_buf *etr_buf;
 	unsigned long size;
 
-	if (cpu == -1)
-		cpu = smp_processor_id();
-	node = cpu_to_node(cpu);
-
+	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
 	/*
 	 * Try to match the perf ring buffer size if it is larger
 	 * than the size requested via sysfs.

2.17.1


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From: Suzuki K Poulose <[email protected]>

During a perf session we try to allocate buffers on the "node" associated with the CPU the event is bound to. If it is not bound to a CPU, we use the current CPU node, using smp_processor_id(). However this is unsafe in a pre-emptible context and could generate the splats as below :

 BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544
 caller is tmc_alloc_etf_buffer+0x5c/0x60
 CPU: 2 PID: 2544 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344
 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb  1 2019
 Call trace:
  dump_backtrace+0x0/0x150
  show_stack+0x14/0x20
  dump_stack+0x9c/0xc4
  debug_smp_processor_id+0x10c/0x110
  tmc_alloc_etf_buffer+0x5c/0x60
  etm_setup_aux+0x1c4/0x230
  rb_alloc_aux+0x1b8/0x2b8
  perf_mmap+0x35c/0x478
  mmap_region+0x34c/0x4f0
  do_mmap+0x2d8/0x418
  vm_mmap_pgoff+0xd0/0xf8
  ksys_mmap_pgoff+0x88/0xf8
  __arm64_sys_mmap+0x28/0x38
  el0_svc_handler+0xd8/0x138
  el0_svc+0x8/0xc

Use NUMA_NO_NODE hint instead of using the current node for events not bound to CPUs.

---
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

index 2527b5d3b65e..8de109de171f 100644
@@ -378,12 +378,10 @@ static void *tmc_alloc_etf_buffer(struct coresight_device *csdev,
 				  struct perf_event *event, void **pages,
 				  int nr_pages, bool overwrite)
 {
-	int node, cpu = event->cpu;
+	int node;
 	struct cs_buffers *buf;
 
-	if (cpu == -1)
-		cpu = smp_processor_id();
-	node = cpu_to_node(cpu);
+	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
 
 	/* Allocate memory structure for interaction with Perf */
 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);

2.17.1


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From: Suzuki K Poulose <[email protected]>

During a perf session we try to allocate buffers on the "node" associated with the CPU the event is bound to. If it is not bound to a CPU, we use the current CPU node, using smp_processor_id(). However this is unsafe in a pre-emptible context and could generate the splats as below :

 BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544

Use NUMA_NO_NODE hint instead of using the current node for events not bound to CPUs.

---
 drivers/hwtracing/coresight/coresight-etb10.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

index 4ee4c80a4354..543cc3d36e1d 100644
@@ -373,12 +373,10 @@ static void *etb_alloc_buffer(struct coresight_device *csdev,
 			      struct perf_event *event, void **pages,
 			      int nr_pages, bool overwrite)
 {
-	int node, cpu = event->cpu;
+	int node;
 	struct cs_buffers *buf;
 
-	if (cpu == -1)
-		cpu = smp_processor_id();
-	node = cpu_to_node(cpu);
+	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
 
 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
 	if (!buf)

2.17.1


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From: Dan Carpenter <[email protected]>

The "drvdata->atclk" clock is optional, but if it gets set to an error pointer then we're accidentally return an uninitialized variable instead of success.

---
 drivers/hwtracing/coresight/coresight-funnel.c | 1 +
 1 file changed, 1 insertion(+)

index 16b0c0e1e43a..ad6e16c96263 100644
@@ -241,6 +241,7 @@ static int funnel_probe(struct device *dev, struct resource *res)
 	}
 
 	pm_runtime_put(dev);
+	ret = 0;
 
 out_disable_clk:
 	if (ret && !IS_ERR_OR_NULL(drvdata->atclk))

2.17.1


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Hi Greg,

I haven't heard back from this set nor can I find the patches in any of your trees. Given the late state in the cycle I'm not sure what to do, i.e should I do a resend of this set or send you another series to go in the 5.3 merge window - please advise.

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I'll take these for 5.3-rc1 and if anything needs to go in 5.2, we can backport them to stable then.

thanks,

greg k-h

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