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* FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
@ 2020-01-27 15:37 gregkh
  2020-01-27 18:36 ` Tom Zanussi
  0 siblings, 1 reply; 7+ messages in thread
From: gregkh @ 2020-01-27 15:37 UTC (permalink / raw)
  To: rostedt, zanussi; +Cc: stable


The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Date: Mon, 20 Jan 2020 13:07:31 -0500
Subject: [PATCH] tracing: Fix histogram code when expression has same var as
 value

While working on a tool to convert SQL syntex into the histogram language of
the kernel, I discovered the following bug:

 # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >> synthetic_events
 # echo 'hist:keys=pid:start=common_timestamp' > events/sched/sched_waking/trigger
 # echo 'hist:keys=next_pid:delta=common_timestamp-$start,start2=$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger

Would not display any histograms in the sched_switch histogram side.

But if I were to swap the location of

  "delta=common_timestamp-$start" with "start2=$start"

Such that the last line had:

 # echo 'hist:keys=next_pid:start2=$start,delta=common_timestamp-$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger

The histogram works as expected.

What I found out is that the expressions clear out the value once it is
resolved. As the variables are resolved in the order listed, when
processing:

  delta=common_timestamp-$start

The $start is cleared. When it gets to "start2=$start", it errors out with
"unresolved symbol" (which is silent as this happens at the location of the
trace), and the histogram is dropped.

When processing the histogram for variable references, instead of adding a
new reference for a variable used twice, use the same reference. That way,
not only is it more efficient, but the order will no longer matter in
processing of the variables.

From Tom Zanussi:

 "Just to clarify some more about what the problem was is that without
  your patch, we would have two separate references to the same variable,
  and during resolve_var_refs(), they'd both want to be resolved
  separately, so in this case, since the first reference to start wasn't
  part of an expression, it wouldn't get the read-once flag set, so would
  be read normally, and then the second reference would do the read-once
  read and also be read but using read-once.  So everything worked and
  you didn't see a problem:

   from: start2=$start,delta=common_timestamp-$start

  In the second case, when you switched them around, the first reference
  would be resolved by doing the read-once, and following that the second
  reference would try to resolve and see that the variable had already
  been read, so failed as unset, which caused it to short-circuit out and
  not do the trigger action to generate the synthetic event:

   to: delta=common_timestamp-$start,start2=$start

  With your patch, we only have the single resolution which happens
  correctly the one time it's resolved, so this can't happen."

Link: https://lore.kernel.org/r/20200116154216.58ca08eb@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers")
Reviewed-by: Tom Zanuss <zanussi@kernel.org>
Tested-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index d33b046f985a..6ac35b9e195d 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -116,6 +116,7 @@ struct hist_field {
 	struct ftrace_event_field	*field;
 	unsigned long			flags;
 	hist_field_fn_t			fn;
+	unsigned int			ref;
 	unsigned int			size;
 	unsigned int			offset;
 	unsigned int                    is_signed;
@@ -2427,8 +2428,16 @@ static int contains_operator(char *str)
 	return field_op;
 }
 
+static void get_hist_field(struct hist_field *hist_field)
+{
+	hist_field->ref++;
+}
+
 static void __destroy_hist_field(struct hist_field *hist_field)
 {
+	if (--hist_field->ref > 1)
+		return;
+
 	kfree(hist_field->var.name);
 	kfree(hist_field->name);
 	kfree(hist_field->type);
@@ -2470,6 +2479,8 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
 	if (!hist_field)
 		return NULL;
 
+	hist_field->ref = 1;
+
 	hist_field->hist_data = hist_data;
 
 	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
@@ -2665,6 +2676,17 @@ static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
 {
 	unsigned long flags = HIST_FIELD_FL_VAR_REF;
 	struct hist_field *ref_field;
+	int i;
+
+	/* Check if the variable already exists */
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		ref_field = hist_data->var_refs[i];
+		if (ref_field->var.idx == var_field->var.idx &&
+		    ref_field->var.hist_data == var_field->hist_data) {
+			get_hist_field(ref_field);
+			return ref_field;
+		}
+	}
 
 	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
 	if (ref_field) {


^ permalink raw reply related	[flat|nested] 7+ messages in thread

* Re: FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
  2020-01-27 15:37 FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree gregkh
@ 2020-01-27 18:36 ` Tom Zanussi
  2020-01-27 18:51   ` Steven Rostedt
  0 siblings, 1 reply; 7+ messages in thread
From: Tom Zanussi @ 2020-01-27 18:36 UTC (permalink / raw)
  To: gregkh, rostedt; +Cc: stable

Hi Steve,

For 4.19, this patch applies if these patches are applied first:

commit 656fe2ba85e81d00e4447bf77b8da2be3c47acb2
Author: Tom Zanussi <tom.zanussi@linux.intel.com>
Date:   Tue Dec 18 14:33:24 2018 -0600

    tracing: Use hist trigger's var_ref array to destroy var_refs

commit de40f033d4e84e843d6a12266e3869015ea9097c
Author: Tom Zanussi <tom.zanussi@linux.intel.com>
Date:   Tue Dec 18 14:33:23 2018 -0600

    tracing: Remove open-coding of hist trigger var_ref management

After applying all 3 to 4.19, I built and ran the ftrace/trigger
selftests and didn't see any problems.

Tom


On Mon, 2020-01-27 at 16:37 +0100, gregkh@linuxfoundation.org wrote:
> The patch below does not apply to the 4.19-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git
> commit
> id to <stable@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 Mon Sep 17 00:00:00
> 2001
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> Date: Mon, 20 Jan 2020 13:07:31 -0500
> Subject: [PATCH] tracing: Fix histogram code when expression has same
> var as
>  value
> 
> While working on a tool to convert SQL syntex into the histogram
> language of
> the kernel, I discovered the following bug:
> 
>  # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >>
> synthetic_events
>  # echo 'hist:keys=pid:start=common_timestamp' >
> events/sched/sched_waking/trigger
>  # echo 'hist:keys=next_pid:delta=common_timestamp-
> $start,start2=$start:onmatch(sched.sched_waking).trace(first,$start2,
> common_timestamp,next_pid,$delta)' >
> events/sched/sched_switch/trigger
> 
> Would not display any histograms in the sched_switch histogram side.
> 
> But if I were to swap the location of
> 
>   "delta=common_timestamp-$start" with "start2=$start"
> 
> Such that the last line had:
> 
>  # echo 'hist:keys=next_pid:start2=$start,delta=common_timestamp-
> $start:onmatch(sched.sched_waking).trace(first,$start2,common_timesta
> mp,next_pid,$delta)' > events/sched/sched_switch/trigger
> 
> The histogram works as expected.
> 
> What I found out is that the expressions clear out the value once it
> is
> resolved. As the variables are resolved in the order listed, when
> processing:
> 
>   delta=common_timestamp-$start
> 
> The $start is cleared. When it gets to "start2=$start", it errors out
> with
> "unresolved symbol" (which is silent as this happens at the location
> of the
> trace), and the histogram is dropped.
> 
> When processing the histogram for variable references, instead of
> adding a
> new reference for a variable used twice, use the same reference. That
> way,
> not only is it more efficient, but the order will no longer matter in
> processing of the variables.
> 
> From Tom Zanussi:
> 
>  "Just to clarify some more about what the problem was is that
> without
>   your patch, we would have two separate references to the same
> variable,
>   and during resolve_var_refs(), they'd both want to be resolved
>   separately, so in this case, since the first reference to start
> wasn't
>   part of an expression, it wouldn't get the read-once flag set, so
> would
>   be read normally, and then the second reference would do the read-
> once
>   read and also be read but using read-once.  So everything worked
> and
>   you didn't see a problem:
> 
>    from: start2=$start,delta=common_timestamp-$start
> 
>   In the second case, when you switched them around, the first
> reference
>   would be resolved by doing the read-once, and following that the
> second
>   reference would try to resolve and see that the variable had
> already
>   been read, so failed as unset, which caused it to short-circuit out
> and
>   not do the trigger action to generate the synthetic event:
> 
>    to: delta=common_timestamp-$start,start2=$start
> 
>   With your patch, we only have the single resolution which happens
>   correctly the one time it's resolved, so this can't happen."
> 
> Link: https://lore.kernel.org/r/20200116154216.58ca08eb@gandalf.local
> .home
> 
> Cc: stable@vger.kernel.org
> Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to
> hist triggers")
> Reviewed-by: Tom Zanuss <zanussi@kernel.org>
> Tested-by: Tom Zanussi <zanussi@kernel.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> 
> diff --git a/kernel/trace/trace_events_hist.c
> b/kernel/trace/trace_events_hist.c
> index d33b046f985a..6ac35b9e195d 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -116,6 +116,7 @@ struct hist_field {
>  	struct ftrace_event_field	*field;
>  	unsigned long			flags;
>  	hist_field_fn_t			fn;
> +	unsigned int			ref;
>  	unsigned int			size;
>  	unsigned int			offset;
>  	unsigned int                    is_signed;
> @@ -2427,8 +2428,16 @@ static int contains_operator(char *str)
>  	return field_op;
>  }
>  
> +static void get_hist_field(struct hist_field *hist_field)
> +{
> +	hist_field->ref++;
> +}
> +
>  static void __destroy_hist_field(struct hist_field *hist_field)
>  {
> +	if (--hist_field->ref > 1)
> +		return;
> +
>  	kfree(hist_field->var.name);
>  	kfree(hist_field->name);
>  	kfree(hist_field->type);
> @@ -2470,6 +2479,8 @@ static struct hist_field
> *create_hist_field(struct hist_trigger_data *hist_data,
>  	if (!hist_field)
>  		return NULL;
>  
> +	hist_field->ref = 1;
> +
>  	hist_field->hist_data = hist_data;
>  
>  	if (flags & HIST_FIELD_FL_EXPR || flags &
> HIST_FIELD_FL_ALIAS)
> @@ -2665,6 +2676,17 @@ static struct hist_field
> *create_var_ref(struct hist_trigger_data *hist_data,
>  {
>  	unsigned long flags = HIST_FIELD_FL_VAR_REF;
>  	struct hist_field *ref_field;
> +	int i;
> +
> +	/* Check if the variable already exists */
> +	for (i = 0; i < hist_data->n_var_refs; i++) {
> +		ref_field = hist_data->var_refs[i];
> +		if (ref_field->var.idx == var_field->var.idx &&
> +		    ref_field->var.hist_data == var_field-
> >hist_data) {
> +			get_hist_field(ref_field);
> +			return ref_field;
> +		}
> +	}
>  
>  	ref_field = create_hist_field(var_field->hist_data, NULL,
> flags, NULL);
>  	if (ref_field) {
> 

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
  2020-01-27 18:36 ` Tom Zanussi
@ 2020-01-27 18:51   ` Steven Rostedt
  2020-01-27 19:19     ` Tom Zanussi
  0 siblings, 1 reply; 7+ messages in thread
From: Steven Rostedt @ 2020-01-27 18:51 UTC (permalink / raw)
  To: Tom Zanussi; +Cc: gregkh, stable

On Mon, 27 Jan 2020 12:36:21 -0600
Tom Zanussi <zanussi@kernel.org> wrote:

> Hi Steve,
> 
> For 4.19, this patch applies if these patches are applied first:
> 
> commit 656fe2ba85e81d00e4447bf77b8da2be3c47acb2
> Author: Tom Zanussi <tom.zanussi@linux.intel.com>
> Date:   Tue Dec 18 14:33:24 2018 -0600
> 
>     tracing: Use hist trigger's var_ref array to destroy var_refs
> 
> commit de40f033d4e84e843d6a12266e3869015ea9097c
> Author: Tom Zanussi <tom.zanussi@linux.intel.com>
> Date:   Tue Dec 18 14:33:23 2018 -0600
> 
>     tracing: Remove open-coding of hist trigger var_ref management
> 
> After applying all 3 to 4.19, I built and ran the ftrace/trigger
> selftests and didn't see any problems.
> 

Thanks, I was cherry-picking parts of those changes, but it wasn't
fixing the issue itself. Let me just backport both of them in full and
see if that works.

-- Steve

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
  2020-01-27 18:51   ` Steven Rostedt
@ 2020-01-27 19:19     ` Tom Zanussi
  2020-01-27 19:36       ` Steven Rostedt
  0 siblings, 1 reply; 7+ messages in thread
From: Tom Zanussi @ 2020-01-27 19:19 UTC (permalink / raw)
  To: Steven Rostedt; +Cc: gregkh, stable

On Mon, 2020-01-27 at 13:51 -0500, Steven Rostedt wrote:
> On Mon, 27 Jan 2020 12:36:21 -0600
> Tom Zanussi <zanussi@kernel.org> wrote:
> 
> > Hi Steve,
> > 
> > For 4.19, this patch applies if these patches are applied first:
> > 
> > commit 656fe2ba85e81d00e4447bf77b8da2be3c47acb2
> > Author: Tom Zanussi <tom.zanussi@linux.intel.com>
> > Date:   Tue Dec 18 14:33:24 2018 -0600
> > 
> >     tracing: Use hist trigger's var_ref array to destroy var_refs
> > 
> > commit de40f033d4e84e843d6a12266e3869015ea9097c
> > Author: Tom Zanussi <tom.zanussi@linux.intel.com>
> > Date:   Tue Dec 18 14:33:23 2018 -0600
> > 
> >     tracing: Remove open-coding of hist trigger var_ref management
> > 
> > After applying all 3 to 4.19, I built and ran the ftrace/trigger
> > selftests and didn't see any problems.
> > 
> 
> Thanks, I was cherry-picking parts of those changes, but it wasn't
> fixing the issue itself. Let me just backport both of them in full
> and
> see if that works.

It does fix the issue for me and passes the selftests.  Remember that
4.19 doesn't have the .trace() hist action - you need to use the event
name e.g. .first()

Tom

> 
> -- Steve

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
  2020-01-27 19:19     ` Tom Zanussi
@ 2020-01-27 19:36       ` Steven Rostedt
  2020-01-27 22:31         ` Steven Rostedt
  0 siblings, 1 reply; 7+ messages in thread
From: Steven Rostedt @ 2020-01-27 19:36 UTC (permalink / raw)
  To: Tom Zanussi; +Cc: gregkh, stable

On Mon, 27 Jan 2020 13:19:28 -0600
Tom Zanussi <zanussi@kernel.org> wrote:

> It does fix the issue for me and passes the selftests.  Remember that
> 4.19 doesn't have the .trace() hist action - you need to use the event
> name e.g. .first()

Yeah I did that, but it was still clearing out the start variable when
I tried. I'll test the full commits next, right after I fix my git repo
that got corrupted because it had an alternative based on a repo that
rebased :-(

-- Steve

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
  2020-01-27 19:36       ` Steven Rostedt
@ 2020-01-27 22:31         ` Steven Rostedt
  2020-01-28  8:02           ` Greg KH
  0 siblings, 1 reply; 7+ messages in thread
From: Steven Rostedt @ 2020-01-27 22:31 UTC (permalink / raw)
  To: Tom Zanussi; +Cc: gregkh, stable

On Mon, 27 Jan 2020 14:36:24 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Mon, 27 Jan 2020 13:19:28 -0600
> Tom Zanussi <zanussi@kernel.org> wrote:
> 
> > It does fix the issue for me and passes the selftests.  Remember that
> > 4.19 doesn't have the .trace() hist action - you need to use the event
> > name e.g. .first()  
> 
> Yeah I did that, but it was still clearing out the start variable when
> I tried. I'll test the full commits next, right after I fix my git repo
> that got corrupted because it had an alternative based on a repo that
> rebased :-(
> 

Finally got my repo fixed. Yes, after applying the two commits, this
failed patch applies fine, and it does fix the issue. The test I did:

 # mount -t tracefs nodev /sys/kernel/tracing
 # cd /sys/kernel/tracing
 # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >> synthetic_events
 # echo 'hist:keys=pid:start=common_timestamp' > events/sched/sched_waking/trigger 
 # echo 'hist:keys=next_pid:delta=common_timestamp-$start,start2=$start:onmatch(sched.sched_waking).first($start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger
 # cat events/sched/sched_switch/hist

And make sure there were events:

 # cat events/sched/sched_switch/hist 
# event histogram
#
# trigger info: hist:keys=next_pid:vals=hitcount:delta=common_timestamp-$start,start2=$start:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_waking).first($start2,common_timestamp,next_pid,$delta) [active]
#

{ next_pid:       1246 } hitcount:          1
{ next_pid:        153 } hitcount:          1
{ next_pid:         21 } hitcount:          1
{ next_pid:         26 } hitcount:          1
{ next_pid:       1245 } hitcount:          1
{ next_pid:       1613 } hitcount:          1
{ next_pid:       1303 } hitcount:          1
{ next_pid:       1375 } hitcount:          1
{ next_pid:         67 } hitcount:          1
{ next_pid:         41 } hitcount:          1
{ next_pid:         12 } hitcount:          1
{ next_pid:         31 } hitcount:          1
{ next_pid:         46 } hitcount:          1
{ next_pid:         36 } hitcount:          1
{ next_pid:         16 } hitcount:          1
{ next_pid:        606 } hitcount:          3
{ next_pid:        102 } hitcount:          3
{ next_pid:        936 } hitcount:          3
{ next_pid:         13 } hitcount:          6
{ next_pid:         10 } hitcount:          7
{ next_pid:       1584 } hitcount:         13
{ next_pid:       1579 } hitcount:         27
{ next_pid:        145 } hitcount:         30
{ next_pid:       1417 } hitcount:         33

Totals:
    Hits: 140
    Entries: 24
    Dropped: 0

Greg,

This patch is dependent on commits
656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and
de40f033d4e84e843d6a12266e3869015ea9097c

Can you backport them as well to 4.19 and then apply this fix?

Thanks!

-- Steve

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree
  2020-01-27 22:31         ` Steven Rostedt
@ 2020-01-28  8:02           ` Greg KH
  0 siblings, 0 replies; 7+ messages in thread
From: Greg KH @ 2020-01-28  8:02 UTC (permalink / raw)
  To: Steven Rostedt; +Cc: Tom Zanussi, stable

On Mon, Jan 27, 2020 at 05:31:09PM -0500, Steven Rostedt wrote:
> On Mon, 27 Jan 2020 14:36:24 -0500
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > On Mon, 27 Jan 2020 13:19:28 -0600
> > Tom Zanussi <zanussi@kernel.org> wrote:
> > 
> > > It does fix the issue for me and passes the selftests.  Remember that
> > > 4.19 doesn't have the .trace() hist action - you need to use the event
> > > name e.g. .first()  
> > 
> > Yeah I did that, but it was still clearing out the start variable when
> > I tried. I'll test the full commits next, right after I fix my git repo
> > that got corrupted because it had an alternative based on a repo that
> > rebased :-(
> > 
> 
> Finally got my repo fixed. Yes, after applying the two commits, this
> failed patch applies fine, and it does fix the issue. The test I did:
> 
>  # mount -t tracefs nodev /sys/kernel/tracing
>  # cd /sys/kernel/tracing
>  # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >> synthetic_events
>  # echo 'hist:keys=pid:start=common_timestamp' > events/sched/sched_waking/trigger 
>  # echo 'hist:keys=next_pid:delta=common_timestamp-$start,start2=$start:onmatch(sched.sched_waking).first($start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger
>  # cat events/sched/sched_switch/hist
> 
> And make sure there were events:
> 
>  # cat events/sched/sched_switch/hist 
> # event histogram
> #
> # trigger info: hist:keys=next_pid:vals=hitcount:delta=common_timestamp-$start,start2=$start:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_waking).first($start2,common_timestamp,next_pid,$delta) [active]
> #
> 
> { next_pid:       1246 } hitcount:          1
> { next_pid:        153 } hitcount:          1
> { next_pid:         21 } hitcount:          1
> { next_pid:         26 } hitcount:          1
> { next_pid:       1245 } hitcount:          1
> { next_pid:       1613 } hitcount:          1
> { next_pid:       1303 } hitcount:          1
> { next_pid:       1375 } hitcount:          1
> { next_pid:         67 } hitcount:          1
> { next_pid:         41 } hitcount:          1
> { next_pid:         12 } hitcount:          1
> { next_pid:         31 } hitcount:          1
> { next_pid:         46 } hitcount:          1
> { next_pid:         36 } hitcount:          1
> { next_pid:         16 } hitcount:          1
> { next_pid:        606 } hitcount:          3
> { next_pid:        102 } hitcount:          3
> { next_pid:        936 } hitcount:          3
> { next_pid:         13 } hitcount:          6
> { next_pid:         10 } hitcount:          7
> { next_pid:       1584 } hitcount:         13
> { next_pid:       1579 } hitcount:         27
> { next_pid:        145 } hitcount:         30
> { next_pid:       1417 } hitcount:         33
> 
> Totals:
>     Hits: 140
>     Entries: 24
>     Dropped: 0
> 
> Greg,
> 
> This patch is dependent on commits
> 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and
> de40f033d4e84e843d6a12266e3869015ea9097c
> 
> Can you backport them as well to 4.19 and then apply this fix?

Will do, thanks!

greg k-h

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2020-01-28  8:02 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-01-27 15:37 FAILED: patch "[PATCH] tracing: Fix histogram code when expression has same var as" failed to apply to 4.19-stable tree gregkh
2020-01-27 18:36 ` Tom Zanussi
2020-01-27 18:51   ` Steven Rostedt
2020-01-27 19:19     ` Tom Zanussi
2020-01-27 19:36       ` Steven Rostedt
2020-01-27 22:31         ` Steven Rostedt
2020-01-28  8:02           ` Greg KH

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