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 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply index 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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