[PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

Ani Sinha posted 1 patch 1 week, 6 days ago
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Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/libvirt tags/patchew/20220111181339.434963-1-ani@anisinha.ca
src/ch/ch_driver.c     |  2 --
src/qemu/qemu_driver.c |  7 +------
src/util/virprocess.c  | 17 +++++++++++++----
3 files changed, 14 insertions(+), 12 deletions(-)

[PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

Posted by Ani Sinha 1 week, 6 days ago
Currently virProcessGetStatInfo() always returns success and only logs error
when it is unable to parse the data. Make this function actually report the
error and return a negative value in this error scenario.

Fix the callers so that they do not override the error generated.
Also fix non-linux implementation of this function so as to report error.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
---
 src/ch/ch_driver.c     |  2 --
 src/qemu/qemu_driver.c |  7 +------
 src/util/virprocess.c  | 17 +++++++++++++----
 3 files changed, 14 insertions(+), 12 deletions(-)

changelog:
v4: on freebsd error on the logs is a problem appaently. try to fix
that.
v3: fix non linux implementation
v2: fix callers

diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c
index 53e0872207..3cbc668489 100644
--- a/src/ch/ch_driver.c
+++ b/src/ch/ch_driver.c
@@ -1073,8 +1073,6 @@ chDomainHelperGetVcpus(virDomainObj *vm,
             if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
                                       &vcpuinfo->cpu, NULL,
                                       vm->pid, vcpupid) < 0) {
-                virReportSystemError(errno, "%s",
-                                      _("cannot get vCPU placement & pCPU time"));
                 return -1;
             }
         }
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index d3d76c003f..65ac5ef367 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -1359,8 +1359,6 @@ qemuDomainHelperGetVcpus(virDomainObj *vm,
             if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
                                       &vcpuinfo->cpu, NULL,
                                       vm->pid, vcpupid) < 0) {
-                virReportSystemError(errno, "%s",
-                                     _("cannot get vCPU placement & pCPU time"));
                 return -1;
             }
         }
@@ -2521,8 +2519,6 @@ qemuDomainGetInfo(virDomainPtr dom,
     if (virDomainObjIsActive(vm)) {
         if (virProcessGetStatInfo(&(info->cpuTime), NULL, NULL,
                                   vm->pid, 0) < 0) {
-            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
-                           _("cannot read cputime for domain"));
             goto cleanup;
         }
     }
@@ -10530,8 +10526,7 @@ qemuDomainMemoryStatsInternal(virQEMUDriver *driver,
     }
 
     if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
-        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
-                       _("cannot get RSS for domain"));
+        virResetLastError();
     } else {
         stats[ret].tag = VIR_DOMAIN_MEMORY_STAT_RSS;
         stats[ret].val = rss;
diff --git a/src/util/virprocess.c b/src/util/virprocess.c
index b559a4257e..cbb31441cc 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -1779,12 +1779,20 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
     long rss = 0;
     int cpu = 0;
 
-    if (!proc_stat ||
-        virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10, &usertime) < 0 ||
+    if (!proc_stat) {
+        VIR_WARN("Unable to get proc stats from the kernel");
+        return 0;
+    }
+
+    if (virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10, &usertime) < 0 ||
         virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &systime) < 0 ||
         virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 ||
         virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) {
-        VIR_WARN("cannot parse process status data");
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("cannot parse process status data for pid '%d/%d'"),
+                       (int) pid, (int) tid);
+
+        return -1;
     }
 
     /* We got jiffies
@@ -1881,7 +1889,8 @@ virProcessGetStatInfo(unsigned long long *cpuTime G_GNUC_UNUSED,
                       pid_t pid G_GNUC_UNUSED,
                       pid_t tid G_GNUC_UNUSED)
 {
-    errno = ENOSYS;
+    virReportSystemError(ENOSYS, "%s",
+                         _("Process statistics data is not supported on this platform"));
     return -1;
 }
 
-- 
2.25.1

Re: [PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

Posted by Michal Prívozník 1 week, 5 days ago
On 1/11/22 19:13, Ani Sinha wrote:
> Currently virProcessGetStatInfo() always returns success and only logs error
> when it is unable to parse the data. Make this function actually report the
> error and return a negative value in this error scenario.
> 
> Fix the callers so that they do not override the error generated.
> Also fix non-linux implementation of this function so as to report error.
> 
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
>  src/ch/ch_driver.c     |  2 --
>  src/qemu/qemu_driver.c |  7 +------
>  src/util/virprocess.c  | 17 +++++++++++++----
>  3 files changed, 14 insertions(+), 12 deletions(-)
> 
> changelog:
> v4: on freebsd error on the logs is a problem appaently. try to fix
> that.
> v3: fix non linux implementation
> v2: fix callers
> 
> diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c
> index 53e0872207..3cbc668489 100644
> --- a/src/ch/ch_driver.c
> +++ b/src/ch/ch_driver.c
> @@ -1073,8 +1073,6 @@ chDomainHelperGetVcpus(virDomainObj *vm,
>              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
>                                        &vcpuinfo->cpu, NULL,
>                                        vm->pid, vcpupid) < 0) {
> -                virReportSystemError(errno, "%s",
> -                                      _("cannot get vCPU placement & pCPU time"));
>                  return -1;
>              }
>          }
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index d3d76c003f..65ac5ef367 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -1359,8 +1359,6 @@ qemuDomainHelperGetVcpus(virDomainObj *vm,
>              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
>                                        &vcpuinfo->cpu, NULL,
>                                        vm->pid, vcpupid) < 0) {
> -                virReportSystemError(errno, "%s",
> -                                     _("cannot get vCPU placement & pCPU time"));
>                  return -1;
>              }
>          }
> @@ -2521,8 +2519,6 @@ qemuDomainGetInfo(virDomainPtr dom,
>      if (virDomainObjIsActive(vm)) {
>          if (virProcessGetStatInfo(&(info->cpuTime), NULL, NULL,
>                                    vm->pid, 0) < 0) {
> -            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> -                           _("cannot read cputime for domain"));
>              goto cleanup;
>          }
>      }
> @@ -10530,8 +10526,7 @@ qemuDomainMemoryStatsInternal(virQEMUDriver *driver,
>      }
>  
>      if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
> -        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> -                       _("cannot get RSS for domain"));
> +        virResetLastError();
>      } else {
>          stats[ret].tag = VIR_DOMAIN_MEMORY_STAT_RSS;
>          stats[ret].val = rss;
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index b559a4257e..cbb31441cc 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -1779,12 +1779,20 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
>      long rss = 0;
>      int cpu = 0;
>  
> -    if (!proc_stat ||
> -        virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10, &usertime) < 0 ||
> +    if (!proc_stat) {
> +        VIR_WARN("Unable to get proc stats from the kernel");
> +        return 0;
> +    }
> +

I don't think I've objected to this part in v3, any reason for changing
it? Because now it's actually worse. For instance in
qemuDomainMemoryStatsInternal() there's the following:

long rss;

virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0);

Now, if virProcessGetStatInfo() returns 0 is @rss set? Depends whether
@proc_stat was NULL or not. But the caller has no way of figuring that out.

I believe all I wanted for you to do was to not change the semantics of
qemuDomainMemoryStatsInternal(). I even suggested how to do that.

Given how long we are discussing this, let me fix your v3 and merge it.

Michal

Re: [PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

Posted by Ani Sinha 1 week, 5 days ago
On Wed, Jan 12, 2022 at 6:49 PM Michal Prívozník <mprivozn@redhat.com>
wrote:

> On 1/11/22 19:13, Ani Sinha wrote:
> > Currently virProcessGetStatInfo() always returns success and only logs
> error
> > when it is unable to parse the data. Make this function actually report
> the
> > error and return a negative value in this error scenario.
> >
> > Fix the callers so that they do not override the error generated.
> > Also fix non-linux implementation of this function so as to report error.
> >
> > Signed-off-by: Ani Sinha <ani@anisinha.ca>
> > ---
> >  src/ch/ch_driver.c     |  2 --
> >  src/qemu/qemu_driver.c |  7 +------
> >  src/util/virprocess.c  | 17 +++++++++++++----
> >  3 files changed, 14 insertions(+), 12 deletions(-)
> >
> > changelog:
> > v4: on freebsd error on the logs is a problem appaently. try to fix
> > that.
> > v3: fix non linux implementation
> > v2: fix callers
> >
> > diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c
> > index 53e0872207..3cbc668489 100644
> > --- a/src/ch/ch_driver.c
> > +++ b/src/ch/ch_driver.c
> > @@ -1073,8 +1073,6 @@ chDomainHelperGetVcpus(virDomainObj *vm,
> >              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
> >                                        &vcpuinfo->cpu, NULL,
> >                                        vm->pid, vcpupid) < 0) {
> > -                virReportSystemError(errno, "%s",
> > -                                      _("cannot get vCPU placement &
> pCPU time"));
> >                  return -1;
> >              }
> >          }
> > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> > index d3d76c003f..65ac5ef367 100644
> > --- a/src/qemu/qemu_driver.c
> > +++ b/src/qemu/qemu_driver.c
> > @@ -1359,8 +1359,6 @@ qemuDomainHelperGetVcpus(virDomainObj *vm,
> >              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
> >                                        &vcpuinfo->cpu, NULL,
> >                                        vm->pid, vcpupid) < 0) {
> > -                virReportSystemError(errno, "%s",
> > -                                     _("cannot get vCPU placement &
> pCPU time"));
> >                  return -1;
> >              }
> >          }
> > @@ -2521,8 +2519,6 @@ qemuDomainGetInfo(virDomainPtr dom,
> >      if (virDomainObjIsActive(vm)) {
> >          if (virProcessGetStatInfo(&(info->cpuTime), NULL, NULL,
> >                                    vm->pid, 0) < 0) {
> > -            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> > -                           _("cannot read cputime for domain"));
> >              goto cleanup;
> >          }
> >      }
> > @@ -10530,8 +10526,7 @@ qemuDomainMemoryStatsInternal(virQEMUDriver
> *driver,
> >      }
> >
> >      if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
> > -        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> > -                       _("cannot get RSS for domain"));
> > +        virResetLastError();
> >      } else {
> >          stats[ret].tag = VIR_DOMAIN_MEMORY_STAT_RSS;
> >          stats[ret].val = rss;
> > diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> > index b559a4257e..cbb31441cc 100644
> > --- a/src/util/virprocess.c
> > +++ b/src/util/virprocess.c
> > @@ -1779,12 +1779,20 @@ virProcessGetStatInfo(unsigned long long
> *cpuTime,
> >      long rss = 0;
> >      int cpu = 0;
> >
> > -    if (!proc_stat ||
> > -        virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10,
> &usertime) < 0 ||
> > +    if (!proc_stat) {
> > +        VIR_WARN("Unable to get proc stats from the kernel");
> > +        return 0;
> > +    }
> > +
>
> I don't think I've objected to this part in v3, any reason for changing
> it? Because now it's actually worse. For instance in
> qemuDomainMemoryStatsInternal() there's the following:
>
> long rss;
>
> virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0);
>
> Now, if virProcessGetStatInfo() returns 0 is @rss set? Depends whether
> @proc_stat was NULL or not. But the caller has no way of figuring that out.
>
> I believe all I wanted for you to do was to not change the semantics of
> qemuDomainMemoryStatsInternal(). I even suggested how to do that.


Yes I did that in v4.
     }

     if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
-        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
-                       _("cannot get RSS for domain"));
+        virResetLastError();

I was also trying to find a solution for the logging issue as well as a
part of v4 which clearly was incorrect.


>

Re: [PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

Posted by Ani Sinha 1 week, 6 days ago
I just realized after sending this patch that I made the change in the
Linux version of the function. It may not be applicable for FreeBSD .
In any case I simply don’t understand if errors on the logs is a problem.
If it is maybe we need a FreeBSD version of this function as well not just
a larger bucket on non Linux flavours that report error .

On Tue, Jan 11, 2022 at 23:43 Ani Sinha <ani@anisinha.ca> wrote:

> Currently virProcessGetStatInfo() always returns success and only logs
> error
> when it is unable to parse the data. Make this function actually report the
> error and return a negative value in this error scenario.
>
> Fix the callers so that they do not override the error generated.
> Also fix non-linux implementation of this function so as to report error.
>
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
>  src/ch/ch_driver.c     |  2 --
>  src/qemu/qemu_driver.c |  7 +------
>  src/util/virprocess.c  | 17 +++++++++++++----
>  3 files changed, 14 insertions(+), 12 deletions(-)
>
> changelog:
> v4: on freebsd error on the logs is a problem appaently. try to fix
> that.
> v3: fix non linux implementation
> v2: fix callers
>
> diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c
> index 53e0872207..3cbc668489 100644
> --- a/src/ch/ch_driver.c
> +++ b/src/ch/ch_driver.c
> @@ -1073,8 +1073,6 @@ chDomainHelperGetVcpus(virDomainObj *vm,
>              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
>                                        &vcpuinfo->cpu, NULL,
>                                        vm->pid, vcpupid) < 0) {
> -                virReportSystemError(errno, "%s",
> -                                      _("cannot get vCPU placement & pCPU
> time"));
>                  return -1;
>              }
>          }
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index d3d76c003f..65ac5ef367 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -1359,8 +1359,6 @@ qemuDomainHelperGetVcpus(virDomainObj *vm,
>              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
>                                        &vcpuinfo->cpu, NULL,
>                                        vm->pid, vcpupid) < 0) {
> -                virReportSystemError(errno, "%s",
> -                                     _("cannot get vCPU placement & pCPU
> time"));
>                  return -1;
>              }
>          }
> @@ -2521,8 +2519,6 @@ qemuDomainGetInfo(virDomainPtr dom,
>      if (virDomainObjIsActive(vm)) {
>          if (virProcessGetStatInfo(&(info->cpuTime), NULL, NULL,
>                                    vm->pid, 0) < 0) {
> -            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> -                           _("cannot read cputime for domain"));
>              goto cleanup;
>          }
>      }
> @@ -10530,8 +10526,7 @@ qemuDomainMemoryStatsInternal(virQEMUDriver
> *driver,
>      }
>
>      if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
> -        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> -                       _("cannot get RSS for domain"));
> +        virResetLastError();
>      } else {
>          stats[ret].tag = VIR_DOMAIN_MEMORY_STAT_RSS;
>          stats[ret].val = rss;
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index b559a4257e..cbb31441cc 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -1779,12 +1779,20 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
>      long rss = 0;
>      int cpu = 0;
>
> -    if (!proc_stat ||
> -        virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10,
> &usertime) < 0 ||
> +    if (!proc_stat) {
> +        VIR_WARN("Unable to get proc stats from the kernel");
> +        return 0;
> +    }
> +
> +    if (virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10,
> &usertime) < 0 ||
>          virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10,
> &systime) < 0 ||
>          virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) <
> 0 ||
>          virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10,
> &cpu) < 0) {
> -        VIR_WARN("cannot parse process status data");
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("cannot parse process status data for pid
> '%d/%d'"),
> +                       (int) pid, (int) tid);
> +
> +        return -1;
>      }
>
>      /* We got jiffies
> @@ -1881,7 +1889,8 @@ virProcessGetStatInfo(unsigned long long *cpuTime
> G_GNUC_UNUSED,
>                        pid_t pid G_GNUC_UNUSED,
>                        pid_t tid G_GNUC_UNUSED)
>  {
> -    errno = ENOSYS;
> +    virReportSystemError(ENOSYS, "%s",
> +                         _("Process statistics data is not supported on
> this platform"));
>      return -1;
>  }
>
> --
> 2.25.1
>
>

Re: [PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

Posted by Michal Prívozník 1 week, 5 days ago
On 1/11/22 19:20, Ani Sinha wrote:
> I just realized after sending this patch that I made the change in the
> Linux version of the function. It may not be applicable for FreeBSD . 
> In any case I simply don’t understand if errors on the logs is a
> problem. If it is maybe we need a FreeBSD version of this function as
> well not just a larger bucket on non Linux flavours that report error .

Please don't top post on technical lists.

Well, I wouldn't be happy if a service was polluting my logs regularly,
would you?

Michal