From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH v4 1/4] coresight: tmc-etr: Do not call smp_processor_id() from preemptible
Date: Thu, 6 Jun 2019 17:16:44 +0100 [thread overview]
Message-ID: <1559837807-15447-2-git-send-email-suzuki.poulose@arm.com> (raw)
In-Reply-To: <1559837807-15447-1-git-send-email-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'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.
Fixes: 855ab61c16bf70b646 ("coresight: tmc-etr: Refactor function tmc_etr_setup_perf_buf()")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index ce0114a..7c81f63 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1323,13 +1323,11 @@ 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)
--
2.7.4
next prev parent reply other threads:[~2019-06-06 16:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 16:16 [PATCH v4 0/4] coresight: Do not call smp_processor_id from pre-emptible contexts Suzuki K Poulose
2019-06-06 16:16 ` Suzuki K Poulose [this message]
2019-06-06 16:16 ` [PATCH v4 2/4] coresight: tmc-etr: alloc_perf_buf: Do not call smp_processor_id from preemptible Suzuki K Poulose
2019-06-06 16:16 ` [PATCH v4 3/4] coresight: tmc-etf: " Suzuki K Poulose
2019-06-06 16:16 ` [PATCH v4 4/4] coresight: etb10: " Suzuki K Poulose
2019-06-06 17:46 ` [PATCH v4 0/4] coresight: Do not call smp_processor_id from pre-emptible contexts Mathieu Poirier
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