| Message ID | 20190619195318.19254-22-mathieu.poirier@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 3a8710392db2c70f74aed6f06b16e8bec0f05a35 |
| Headers | show |
| Series | coresight: next v5.2-rc5 (V2) | expand |
On Wed, Jun 19, 2019 at 01:53:11PM -0600, Mathieu Poirier wrote: > 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> > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Same here, why isn't this 5.2-final and stable@vger.kernel.org material?
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 7c81f634ecb4..5d2bf6d18961 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1184,14 +1184,11 @@ 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.