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Groups > linux.kernel > #1212260

[PATCH v2 3/6] perf: Annotate some of the error codes with perf_err()

From Alexander Shishkin <alexander.shishkin@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCH v2 3/6] perf: Annotate some of the error codes with perf_err()
Date 2015-08-24 16:40 +0200
Message-ID <q114L-23E-27@gated-at.bofh.it> (permalink)
References <q114K-23E-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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This patch annotates a few semi-random error paths in perf core to
illustrate the extended error reporting facility. Most of them can
be triggered from perf tools.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
 kernel/events/core.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3ff28fc8bd..7beab37ea6 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3382,10 +3382,10 @@ find_lively_task_by_vpid(pid_t vpid)
 	rcu_read_unlock();
 
 	if (!task)
-		return ERR_PTR(-ESRCH);
+		return PERF_ERR_PTR(-ESRCH, "task not found");
 
 	/* Reuse ptrace permission checks for now. */
-	err = -EACCES;
+	err = perf_err(-EACCES, "insufficient permissions for tracing this task");
 	if (!ptrace_may_access(task, PTRACE_MODE_READ))
 		goto errout;
 
@@ -3413,7 +3413,8 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
 	if (!task) {
 		/* Must be root to operate on a CPU event: */
 		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
-			return ERR_PTR(-EACCES);
+			return PERF_ERR_PTR(-EACCES,
+					    "must be root to operate on a CPU event");
 
 		/*
 		 * We could be clever and allow to attach a event to an
@@ -3421,7 +3422,7 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
 		 * that's for later.
 		 */
 		if (!cpu_online(cpu))
-			return ERR_PTR(-ENODEV);
+			return PERF_ERR_PTR(-ENODEV, "cpu is offline");
 
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
 		ctx = &cpuctx->ctx;
@@ -8134,15 +8135,16 @@ SYSCALL_DEFINE5(perf_event_open,
 
 	if (!attr.exclude_kernel) {
 		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
-			return -EACCES;
+			return perf_err_sync(&attr, -EACCES,
+					     "kernel tracing forbidden for the unprivileged");
 	}
 
 	if (attr.freq) {
 		if (attr.sample_freq > sysctl_perf_event_sample_rate)
-			return -EINVAL;
+			return perf_err_sync(&attr, -EINVAL, "sample_freq too high");
 	} else {
 		if (attr.sample_period & (1ULL << 63))
-			return -EINVAL;
+			return perf_err_sync(&attr, -EINVAL, "sample_period too high");
 	}
 
 	/*
@@ -8152,14 +8154,14 @@ SYSCALL_DEFINE5(perf_event_open,
 	 * cgroup.
 	 */
 	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
-		return -EINVAL;
+		return perf_err_sync(&attr, -EINVAL, "pid and cpu need to be set in cgroup mode");
 
 	if (flags & PERF_FLAG_FD_CLOEXEC)
 		f_flags |= O_CLOEXEC;
 
 	event_fd = get_unused_fd_flags(f_flags);
 	if (event_fd < 0)
-		return event_fd;
+		return perf_err_sync(&attr, event_fd, "can't obtain a file descriptor");
 
 	if (group_fd != -1) {
 		err = perf_fget_light(group_fd, &group);
-- 
2.5.0

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Thread

[PATCH v2 0/6] perf: Introduce extended syscall error reporting Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
  [PATCH v2 5/6] perf/x86/intel/pt: Use extended error reporting in event initialization Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
  [PATCH v2 6/6] perf/x86/intel/bts: Use extended error reporting in event initialization Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
  [PATCH v2 1/6] perf: Introduce extended syscall error reporting Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
    Re: [PATCH v2 1/6] perf: Introduce extended syscall error reporting Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-08-31 20:50 +0200
      Re: [PATCH v2 1/6] perf: Introduce extended syscall error reporting Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-09-01 08:40 +0200
  [PATCH v2 3/6] perf: Annotate some of the error codes with perf_err() Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
  [PATCH v2 2/6] perf: Add file name and line number to perf extended error reports Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
  [PATCH v2 4/6] perf/x86: Annotate some of the error codes with perf_err() Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-24 16:40 +0200
  Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-25 10:30 +0200
  Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Johannes Berg <johannes@sipsolutions.net> - 2015-08-25 11:00 +0200
    Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-25 11:10 +0200
      Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-25 11:20 +0200
        Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Johannes Berg <johannes@sipsolutions.net> - 2015-08-25 11:40 +0200
          Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-25 12:10 +0200
            Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Johannes Berg <johannes@sipsolutions.net> - 2015-08-25 12:30 +0200
              Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-26 07:00 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Johannes Berg <johannes@sipsolutions.net> - 2015-08-26 09:10 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-26 09:30 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-26 19:00 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-08-26 23:00 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Andrew Morton <akpm@linux-foundation.org> - 2015-08-26 20:50 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Peter Zijlstra <peterz@infradead.org> - 2015-08-26 22:10 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Andrew Morton <akpm@linux-foundation.org> - 2015-08-26 22:30 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error  reporting Vince Weaver <vince@deater.net> - 2015-08-26 23:00 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Andrew Morton <akpm@linux-foundation.org> - 2015-08-26 23:00 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error  reporting Vince Weaver <vince@deater.net> - 2015-08-26 23:20 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-28 12:10 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Arnaldo Carvalho de Melo <acme@infradead.org> - 2015-08-26 23:10 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-26 09:30 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Johannes Berg <johannes@sipsolutions.net> - 2015-08-26 09:40 +0200
                Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Ingo Molnar <mingo@kernel.org> - 2015-08-26 09:10 +0200
        Re: [PATCH v2 0/6] perf: Introduce extended syscall error reporting Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-26 13:40 +0200

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