From bc4f359b3b607daac0290d0038561237a86b38cb Mon Sep 17 00:00:00 2001 From: Anton Gusev Date: Tue, 31 Jan 2023 10:58:18 +0300 Subject: [PATCH 1/8] tracing: Fix wrong return in kprobe_event_gen_test.c Overwriting the error code with the deletion result may cause the function to return 0 despite encountering an error. Commit b111545d26c0 ("tracing: Remove the useless value assignment in test_create_synth_event()") solves a similar issue by returning the original error code, so this patch does the same. Found by Linux Verification Center (linuxtesting.org) with SVACE. Link: https://lore.kernel.org/linux-trace-kernel/20230131075818.5322-1-aagusev@ispras.ru Signed-off-by: Anton Gusev Reviewed-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/kprobe_event_gen_test.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c index 4850fdfe27f1..5a4b722b5045 100644 --- a/kernel/trace/kprobe_event_gen_test.c +++ b/kernel/trace/kprobe_event_gen_test.c @@ -146,7 +146,7 @@ static int __init test_gen_kprobe_cmd(void) if (trace_event_file_is_valid(gen_kprobe_test)) gen_kprobe_test = NULL; /* We got an error after creating the event, delete it */ - ret = kprobe_event_delete("gen_kprobe_test"); + kprobe_event_delete("gen_kprobe_test"); goto out; } @@ -211,7 +211,7 @@ static int __init test_gen_kretprobe_cmd(void) if (trace_event_file_is_valid(gen_kretprobe_test)) gen_kretprobe_test = NULL; /* We got an error after creating the event, delete it */ - ret = kprobe_event_delete("gen_kretprobe_test"); + kprobe_event_delete("gen_kretprobe_test"); goto out; } From 7a025e066e0f0afd39cc88a089929ccb945ce9e8 Mon Sep 17 00:00:00 2001 From: Tom Rix Date: Thu, 9 Mar 2023 10:04:14 -0500 Subject: [PATCH 2/8] tracing/osnoise: set several trace_osnoise.c variables storage-class-specifier to static smatch reports several similar warnings kernel/trace/trace_osnoise.c:220:1: warning: symbol '__pcpu_scope_per_cpu_osnoise_var' was not declared. Should it be static? kernel/trace/trace_osnoise.c:243:1: warning: symbol '__pcpu_scope_per_cpu_timerlat_var' was not declared. Should it be static? kernel/trace/trace_osnoise.c:335:14: warning: symbol 'interface_lock' was not declared. Should it be static? kernel/trace/trace_osnoise.c:2242:5: warning: symbol 'timerlat_min_period' was not declared. Should it be static? kernel/trace/trace_osnoise.c:2243:5: warning: symbol 'timerlat_max_period' was not declared. Should it be static? These variables are only used in trace_osnoise.c, so it should be static Link: https://lore.kernel.org/linux-trace-kernel/20230309150414.4036764-1-trix@redhat.com Signed-off-by: Tom Rix Acked-by: Masami Hiramatsu (Google) Acked-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_osnoise.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 04f0fdae19a1..9176bb7a9bb4 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -217,7 +217,7 @@ struct osnoise_variables { /* * Per-cpu runtime information. */ -DEFINE_PER_CPU(struct osnoise_variables, per_cpu_osnoise_var); +static DEFINE_PER_CPU(struct osnoise_variables, per_cpu_osnoise_var); /* * this_cpu_osn_var - Return the per-cpu osnoise_variables on its relative CPU @@ -240,7 +240,7 @@ struct timerlat_variables { u64 count; }; -DEFINE_PER_CPU(struct timerlat_variables, per_cpu_timerlat_var); +static DEFINE_PER_CPU(struct timerlat_variables, per_cpu_timerlat_var); /* * this_cpu_tmr_var - Return the per-cpu timerlat_variables on its relative CPU @@ -332,7 +332,7 @@ struct timerlat_sample { /* * Protect the interface. */ -struct mutex interface_lock; +static struct mutex interface_lock; /* * Tracer data. @@ -2239,8 +2239,8 @@ static struct trace_min_max_param osnoise_print_stack = { /* * osnoise/timerlat_period: min 100 us, max 1 s */ -u64 timerlat_min_period = 100; -u64 timerlat_max_period = 1000000; +static u64 timerlat_min_period = 100; +static u64 timerlat_max_period = 1000000; static struct trace_min_max_param timerlat_period = { .lock = &interface_lock, .val = &osnoise_data.timerlat_period, From 4c42f5f0d1dd20bddd9f940beb1e6ccad60c4498 Mon Sep 17 00:00:00 2001 From: Tero Kristo Date: Fri, 10 Mar 2023 12:04:50 +0200 Subject: [PATCH 3/8] trace/hwlat: Do not wipe the contents of per-cpu thread data Do not wipe the contents of the per-cpu kthread data when starting the tracer, as this will completely forget about already running instances and can later start new additional per-cpu threads. Link: https://lore.kernel.org/all/20230302113654.2984709-1-tero.kristo@linux.intel.com/ Link: https://lkml.kernel.org/r/20230310100451.3948583-2-tero.kristo@linux.intel.com Cc: stable@vger.kernel.org Fixes: f46b16520a087 ("trace/hwlat: Implement the per-cpu mode") Signed-off-by: Tero Kristo Acked-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_hwlat.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index d440ddd5fd8b..edc26dc22c3f 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -584,9 +584,6 @@ static int start_per_cpu_kthreads(struct trace_array *tr) */ cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask); - for_each_online_cpu(cpu) - per_cpu(hwlat_per_cpu_data, cpu).kthread = NULL; - for_each_cpu(cpu, current_mask) { retval = start_cpu_kthread(cpu); if (retval) From 08697bca9bbba15f2058fdbd9f970bd5f6a8a2e8 Mon Sep 17 00:00:00 2001 From: Tero Kristo Date: Fri, 10 Mar 2023 12:04:51 +0200 Subject: [PATCH 4/8] trace/hwlat: Do not start per-cpu thread if it is already running The hwlatd tracer will end up starting multiple per-cpu threads with the following script: #!/bin/sh cd /sys/kernel/debug/tracing echo 0 > tracing_on echo hwlat > current_tracer echo per-cpu > hwlat_detector/mode echo 100000 > hwlat_detector/width echo 200000 > hwlat_detector/window echo 1 > tracing_on To fix the issue, check if the hwlatd thread for the cpu is already running, before starting a new one. Along with the previous patch, this avoids running multiple instances of the same CPU thread on the system. Link: https://lore.kernel.org/all/20230302113654.2984709-1-tero.kristo@linux.intel.com/ Link: https://lkml.kernel.org/r/20230310100451.3948583-3-tero.kristo@linux.intel.com Cc: stable@vger.kernel.org Fixes: f46b16520a087 ("trace/hwlat: Implement the per-cpu mode") Signed-off-by: Tero Kristo Acked-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_hwlat.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index edc26dc22c3f..c4945f8adc11 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -492,6 +492,10 @@ static int start_cpu_kthread(unsigned int cpu) { struct task_struct *kthread; + /* Do not start a new hwlatd thread if it is already running */ + if (per_cpu(hwlat_per_cpu_data, cpu).kthread) + return 0; + kthread = kthread_run_on_cpu(kthread_fn, NULL, cpu, "hwlatd/%u"); if (IS_ERR(kthread)) { pr_err(BANNER "could not start sampling thread\n"); From 8732565549011cabbea08329a1aefd78a68d96c7 Mon Sep 17 00:00:00 2001 From: Tom Rix Date: Sat, 11 Mar 2023 08:51:13 -0500 Subject: [PATCH 5/8] ftrace: Set direct_ops storage-class-specifier to static smatch reports this warning kernel/trace/ftrace.c:2594:19: warning: symbol 'direct_ops' was not declared. Should it be static? The variable direct_ops is only used in ftrace.c, so it should be static Link: https://lore.kernel.org/linux-trace-kernel/20230311135113.711824-1-trix@redhat.com Signed-off-by: Tom Rix Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a47f7d93e32d..ec2897a76004 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2503,7 +2503,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip, arch_ftrace_set_direct_caller(fregs, addr); } -struct ftrace_ops direct_ops = { +static struct ftrace_ops direct_ops = { .func = call_direct_funcs, .flags = FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_PERMANENT, From e400be674a1a40e9dcb2e95f84d6c1fd2d88f31d Mon Sep 17 00:00:00 2001 From: Sung-hun Kim Date: Tue, 14 Mar 2023 10:37:07 +0900 Subject: [PATCH 6/8] tracing: Make splice_read available again Since the commit 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") is applied to the kernel, splice() and sendfile() calls on the trace file (/sys/kernel/debug/tracing /trace) return EINVAL. This patch restores these system calls by initializing splice_read in file_operations of the trace file. This patch only enables such functionalities for the read case. Link: https://lore.kernel.org/linux-trace-kernel/20230314013707.28814-1-sfoon.kim@samsung.com Cc: stable@vger.kernel.org Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Signed-off-by: Sung-hun Kim Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index fbb602a8b64b..4e9a7a952025 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5164,6 +5164,8 @@ loff_t tracing_lseek(struct file *file, loff_t offset, int whence) static const struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = tracing_write_stub, .llseek = tracing_lseek, .release = tracing_release, From a98151ad53b53f010ee364ec2fd06445b328578b Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Wed, 15 Mar 2023 15:24:46 +0100 Subject: [PATCH 7/8] ring-buffer: remove obsolete comment for free_buffer_page() The comment refers to mm/slob.c which is being removed. It comes from commit ed56829cb319 ("ring_buffer: reset buffer page when freeing") and according to Steven the borrowed code was a page mapcount and mapping reset, which was later removed by commit e4c2ce82ca27 ("ring_buffer: allocate buffer page pointer"). Thus the comment is not accurate anyway, remove it. Link: https://lore.kernel.org/linux-trace-kernel/20230315142446.27040-1-vbabka@suse.cz Cc: Masami Hiramatsu Cc: Ingo Molnar Reported-by: Mike Rapoport Suggested-by: Steven Rostedt (Google) Fixes: e4c2ce82ca27 ("ring_buffer: allocate buffer page pointer") Signed-off-by: Vlastimil Babka Reviewed-by: Mukesh Ojha Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 071184324d18..3c7cd135333f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -354,10 +354,6 @@ static void rb_init_page(struct buffer_data_page *bpage) local_set(&bpage->commit, 0); } -/* - * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing - * this issue out. - */ static void free_buffer_page(struct buffer_page *bpage) { free_page((unsigned long)bpage->page); From 71c7a30442b724717a30d5e7d1662ba4904eb3d4 Mon Sep 17 00:00:00 2001 From: Costa Shulyupin Date: Thu, 16 Mar 2023 16:45:35 +0200 Subject: [PATCH 8/8] tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr There is a problem with the behavior of hwlat in a container, resulting in incorrect output. A warning message is generated: "cpumask changed while in round-robin mode, switching to mode none", and the tracing_cpumask is ignored. This issue arises because the kernel thread, hwlatd, is not a part of the container, and the function sched_setaffinity is unable to locate it using its PID. Additionally, the task_struct of hwlatd is already known. Ultimately, the function set_cpus_allowed_ptr achieves the same outcome as sched_setaffinity, but employs task_struct instead of PID. Test case: # cd /sys/kernel/tracing # echo 0 > tracing_on # echo round-robin > hwlat_detector/mode # echo hwlat > current_tracer # unshare --fork --pid bash -c 'echo 1 > tracing_on' # dmesg -c Actual behavior: [573502.809060] hwlat_detector: cpumask changed while in round-robin mode, switching to mode none Link: https://lore.kernel.org/linux-trace-kernel/20230316144535.1004952-1-costa.shul@redhat.com Cc: Masami Hiramatsu Fixes: 0330f7aa8ee63 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Costa Shulyupin Acked-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_hwlat.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index c4945f8adc11..2f37a6e68aa9 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -339,7 +339,7 @@ static void move_to_next_cpu(void) cpumask_clear(current_mask); cpumask_set_cpu(next_cpu, current_mask); - sched_setaffinity(0, current_mask); + set_cpus_allowed_ptr(current, current_mask); return; change_mode: @@ -446,7 +446,7 @@ static int start_single_kthread(struct trace_array *tr) } - sched_setaffinity(kthread->pid, current_mask); + set_cpus_allowed_ptr(kthread, current_mask); kdata->kthread = kthread; wake_up_process(kthread);