From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: gregkh@linuxfoundation.org
Cc: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/5] coresight: tmc-etr: alloc_perf_buf: Do not call smp_processor_id from preemptible
Date: Thu, 20 Jun 2019 16:12:34 -0600 [thread overview]
Message-ID: <20190620221237.3536-3-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20190620221237.3536-1-mathieu.poirier@linaro.org>
From: Suzuki K Poulose <suzuki.poulose@arm.com>
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.
Fixes: 22f429f19c4135d51e9 ("coresight: etm-perf: Add support for ETR backend")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable <stable@vger.kernel.org> # 4.20+
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index c6a36897924f..9f293b9dce8c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -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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next prev parent reply other threads:[~2019-06-20 22:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 22:12 [PATCH 0/5] coresight: Fixes for v5.2-rc5 Mathieu Poirier
2019-06-20 22:12 ` [PATCH 1/5] coresight: tmc-etr: Do not call smp_processor_id() from preemptible Mathieu Poirier
2019-07-03 19:14 ` Greg KH
2019-06-20 22:12 ` Mathieu Poirier [this message]
2019-06-20 22:12 ` [PATCH 3/5] coresight: tmc-etf: Do not call smp_processor_id " Mathieu Poirier
2019-06-20 22:12 ` [PATCH 4/5] coresight: etb10: " Mathieu Poirier
2019-06-20 22:12 ` [PATCH 5/5] coresight: Potential uninitialized variable in probe() Mathieu Poirier
2019-07-02 16:18 ` [PATCH 0/5] coresight: Fixes for v5.2-rc5 Mathieu Poirier
2019-07-03 19:13 ` Greg KH
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