| Message ID | 20190620221237.3536-2-mathieu.poirier@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 3ff44563dbb02456a33f2a42000f04db4ef19a8f |
| Headers | show |
| Series | coresight: Fixes for v5.2-rc5 | expand |
On Thu, Jun 20, 2019 at 04:12:33PM -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'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()") This should be: Fixes: 855ab61c16bf ("coresight: tmc-etr: Refactor function tmc_etr_setup_perf_buf()") Add: [core] abbrev = 12 to your .gitconfig file, we only need 12 in the kernel tree. For now :) thanks, greg k-h
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index df6e4b0b84e9..c6a36897924f 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -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)