| From 024c1fd9dbcc1d8a847f1311f999d35783921b7f Mon Sep 17 00:00:00 2001 |
| From: Suzuki K Poulose <suzuki.poulose@arm.com> |
| Date: Thu, 20 Jun 2019 16:12:35 -0600 |
| Subject: coresight: tmc-etf: Do not call smp_processor_id from preemptible |
| |
| From: Suzuki K Poulose <suzuki.poulose@arm.com> |
| |
| commit 024c1fd9dbcc1d8a847f1311f999d35783921b7f upstream. |
| |
| 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. |
| |
| Fixes: 2e499bbc1a929ac ("coresight: tmc: implementing TMC-ETF AUX space API") |
| Cc: Mathieu Poirier <mathieu.poirier@linaro.org> |
| Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> |
| Cc: stable <stable@vger.kernel.org> # 4.7+ |
| Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> |
| Link: https://lore.kernel.org/r/20190620221237.3536-4-mathieu.poirier@linaro.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/hwtracing/coresight/coresight-tmc-etf.c | 4 +--- |
| 1 file changed, 1 insertion(+), 3 deletions(-) |
| |
| --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c |
| +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c |
| @@ -292,9 +292,7 @@ static void *tmc_alloc_etf_buffer(struct |
| int node; |
| struct cs_buffers *buf; |
| |
| - if (cpu == -1) |
| - cpu = smp_processor_id(); |
| - node = cpu_to_node(cpu); |
| + node = (cpu == -1) ? NUMA_NO_NODE : cpu_to_node(cpu); |
| |
| /* Allocate memory structure for interaction with Perf */ |
| buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node); |