* FAILED: patch "[PATCH] tracing/histograms: Reject non-stacktrace fields for" failed to apply to 6.1-stable tree
@ 2026-10-21 14:42 gregkh
2026-10-21 15:37 ` [PATCH 6.1.y] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2026-10-21 14:42 UTC (permalink / raw)
To: lee, mhiramat, rostedt; +Cc: stable
The patch below does not apply to the 6.1-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>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x a244c241593b5b38a08f0df2cb43c26574efbdcb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026102125-surely-nastily-2d17@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a244c241593b5b38a08f0df2cb43c26574efbdcb Mon Sep 17 00:00:00 2001
From: Lee Jones <lee@kernel.org>
Date: Tue, 13 Oct 2026 11:24:48 +0000
Subject: [PATCH] tracing/histograms: Reject non-stacktrace fields for
synthetic stacktrace fields
In check_synth_field(), when a synthetic event field is a stacktrace
(field->is_stack) and the histogram field is not a "long[" stacktrace
array, validation falls through to the generic size and signedness
comparison.
Because parse_synth_field() sets a stacktrace field's type to
"__data_loc unsigned long[]", its size is sizeof(u64) and
synth_field_signed() marks it as signed. Consequently, any 8-byte
signed scalar histogram field passes the fallback check, and its scalar
value is subsequently dereferenced as a kernel stacktrace pointer in
get_field_size() and trace_stack().
Furthermore, checking strstr(hist_field->type, "long[") is insufficient
because tracepoint fields defined with __bitmask() or __rel_bitmask()
also have type "__data_loc unsigned long[]" or "__rel_loc unsigned
long[]", whilst create_hist_field() treats them as 4-byte scalar values
without HIST_FIELD_FL_STACKTRACE.
Propagate HIST_FIELD_FL_STACKTRACE to variable references and field
variables (whilst excluding variable aliases from per-element
stacktrace capture), and reject any mismatch between
HIST_FIELD_FL_STACKTRACE and field->is_stack in check_synth_field().
Cc: stable@vger.kernel.org
Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces")
Link: https://patch.msgid.link/20261013112449.1006088-1-lee@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 571a57e0f369..dcb5d7321095 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2121,7 +2121,8 @@ static int init_var_ref(struct hist_field *ref_field,
ref_field->size = var_field->size;
ref_field->is_signed = var_field->is_signed;
ref_field->flags |= var_field->flags &
- (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
+ (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS |
+ HIST_FIELD_FL_STACKTRACE);
if (system) {
ref_field->system = kstrdup(system, GFP_KERNEL);
@@ -3318,6 +3319,7 @@ static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
ret = PTR_ERR(var);
goto err;
}
+ var->flags |= val->flags & HIST_FIELD_FL_STACKTRACE;
field_var = kzalloc_obj(struct field_var);
if (!field_var) {
@@ -3946,7 +3948,10 @@ static int check_synth_field(struct synth_event *event,
&& field->is_dynamic)
return 0;
- if (strstr(hist_field->type, "long[") && field->is_stack)
+ if (!!(hist_field->flags & HIST_FIELD_FL_STACKTRACE) != field->is_stack)
+ return -EINVAL;
+
+ if (field->is_stack)
return 0;
if (strcmp(field->type, hist_field->type) != 0) {
@@ -4487,7 +4492,8 @@ static int create_var_field(struct hist_trigger_data *hist_data,
if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
update_var_execname(hist_data->fields[val_idx]);
- if (!ret && hist_data->fields[val_idx]->flags &
+ if (!ret && !(hist_data->fields[val_idx]->flags & HIST_FIELD_FL_ALIAS) &&
+ hist_data->fields[val_idx]->flags &
(HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
@@ -5228,7 +5234,8 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
if (hist_field->flags & HIST_FIELD_FL_VAR) {
var_idx = hist_field->var.idx;
- if (hist_field->flags &
+ if (!(hist_field->flags & HIST_FIELD_FL_ALIAS) &&
+ hist_field->flags &
(HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE)) {
unsigned int str_start, var_str_idx, idx;
char *str, *val_str;
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 6.1.y] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields
2026-10-21 14:42 FAILED: patch "[PATCH] tracing/histograms: Reject non-stacktrace fields for" failed to apply to 6.1-stable tree gregkh
@ 2026-10-21 15:37 ` Sasha Levin
2026-10-22 7:50 ` Lee Jones
0 siblings, 1 reply; 3+ messages in thread
From: Sasha Levin @ 2026-10-21 15:37 UTC (permalink / raw)
To: stable; +Cc: Lee Jones, Masami Hiramatsu (Google), Steven Rostedt, Sasha Levin
From: Lee Jones <lee@kernel.org>
[ Upstream commit a244c241593b5b38a08f0df2cb43c26574efbdcb ]
In check_synth_field(), when a synthetic event field is a stacktrace
(field->is_stack) and the histogram field is not a "long[" stacktrace
array, validation falls through to the generic size and signedness
comparison.
Because parse_synth_field() sets a stacktrace field's type to
"__data_loc unsigned long[]", its size is sizeof(u64) and
synth_field_signed() marks it as signed. Consequently, any 8-byte
signed scalar histogram field passes the fallback check, and its scalar
value is subsequently dereferenced as a kernel stacktrace pointer in
get_field_size() and trace_stack().
Furthermore, checking strstr(hist_field->type, "long[") is insufficient
because tracepoint fields defined with __bitmask() or __rel_bitmask()
also have type "__data_loc unsigned long[]" or "__rel_loc unsigned
long[]", whilst create_hist_field() treats them as 4-byte scalar values
without HIST_FIELD_FL_STACKTRACE.
Propagate HIST_FIELD_FL_STACKTRACE to variable references and field
variables (whilst excluding variable aliases from per-element
stacktrace capture), and reject any mismatch between
HIST_FIELD_FL_STACKTRACE and field->is_stack in check_synth_field().
Cc: stable@vger.kernel.org
Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces")
Link: https://patch.msgid.link/20261013112449.1006088-1-lee@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ sashal: Retained string-only buffer conditions because histogram stacktrace-variable support is absent. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/trace/trace_events_hist.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 40d9de933fc85..f04037d01bdd7 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2067,7 +2067,8 @@ static int init_var_ref(struct hist_field *ref_field,
ref_field->size = var_field->size;
ref_field->is_signed = var_field->is_signed;
ref_field->flags |= var_field->flags &
- (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
+ (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS |
+ HIST_FIELD_FL_STACKTRACE);
if (system) {
ref_field->system = kstrdup(system, GFP_KERNEL);
@@ -3210,6 +3211,7 @@ static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
ret = PTR_ERR(var);
goto err;
}
+ var->flags |= val->flags & HIST_FIELD_FL_STACKTRACE;
field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
if (!field_var) {
@@ -3837,7 +3839,10 @@ static int check_synth_field(struct synth_event *event,
&& field->is_dynamic)
return 0;
- if (strstr(hist_field->type, "long[") && field->is_stack)
+ if (!!(hist_field->flags & HIST_FIELD_FL_STACKTRACE) != field->is_stack)
+ return -EINVAL;
+
+ if (field->is_stack)
return 0;
if (strcmp(field->type, hist_field->type) != 0) {
@@ -4360,7 +4365,8 @@ static int create_var_field(struct hist_trigger_data *hist_data,
if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
update_var_execname(hist_data->fields[val_idx]);
- if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
+ if (!ret && !(hist_data->fields[val_idx]->flags & HIST_FIELD_FL_ALIAS) &&
+ hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
return ret;
@@ -5093,7 +5099,8 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
if (hist_field->flags & HIST_FIELD_FL_VAR) {
var_idx = hist_field->var.idx;
- if (hist_field->flags & HIST_FIELD_FL_STRING) {
+ if (!(hist_field->flags & HIST_FIELD_FL_ALIAS) &&
+ hist_field->flags & HIST_FIELD_FL_STRING) {
unsigned int str_start, var_str_idx, idx;
char *str, *val_str;
unsigned int size;
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 6.1.y] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields
2026-10-21 15:37 ` [PATCH 6.1.y] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields Sasha Levin
@ 2026-10-22 7:50 ` Lee Jones
0 siblings, 0 replies; 3+ messages in thread
From: Lee Jones @ 2026-10-22 7:50 UTC (permalink / raw)
To: Sasha Levin; +Cc: stable, Masami Hiramatsu (Google), Steven Rostedt
On Wed, 21 Oct 2026, Sasha Levin wrote:
> From: Lee Jones <lee@kernel.org>
>
> [ Upstream commit a244c241593b5b38a08f0df2cb43c26574efbdcb ]
>
> In check_synth_field(), when a synthetic event field is a stacktrace
> (field->is_stack) and the histogram field is not a "long[" stacktrace
> array, validation falls through to the generic size and signedness
> comparison.
>
> Because parse_synth_field() sets a stacktrace field's type to
> "__data_loc unsigned long[]", its size is sizeof(u64) and
> synth_field_signed() marks it as signed. Consequently, any 8-byte
> signed scalar histogram field passes the fallback check, and its scalar
> value is subsequently dereferenced as a kernel stacktrace pointer in
> get_field_size() and trace_stack().
>
> Furthermore, checking strstr(hist_field->type, "long[") is insufficient
> because tracepoint fields defined with __bitmask() or __rel_bitmask()
> also have type "__data_loc unsigned long[]" or "__rel_loc unsigned
> long[]", whilst create_hist_field() treats them as 4-byte scalar values
> without HIST_FIELD_FL_STACKTRACE.
>
> Propagate HIST_FIELD_FL_STACKTRACE to variable references and field
> variables (whilst excluding variable aliases from per-element
> stacktrace capture), and reject any mismatch between
> HIST_FIELD_FL_STACKTRACE and field->is_stack in check_synth_field().
>
> Cc: stable@vger.kernel.org
> Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces")
> Link: https://patch.msgid.link/20261013112449.1006088-1-lee@kernel.org
> Signed-off-by: Lee Jones <lee@kernel.org>
> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> [ sashal: Retained string-only buffer conditions because histogram stacktrace-variable support is absent. ]
Nice. Thanks Robo Sasha!
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> kernel/trace/trace_events_hist.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 40d9de933fc85..f04037d01bdd7 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -2067,7 +2067,8 @@ static int init_var_ref(struct hist_field *ref_field,
> ref_field->size = var_field->size;
> ref_field->is_signed = var_field->is_signed;
> ref_field->flags |= var_field->flags &
> - (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
> + (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS |
> + HIST_FIELD_FL_STACKTRACE);
>
> if (system) {
> ref_field->system = kstrdup(system, GFP_KERNEL);
> @@ -3210,6 +3211,7 @@ static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
> ret = PTR_ERR(var);
> goto err;
> }
> + var->flags |= val->flags & HIST_FIELD_FL_STACKTRACE;
>
> field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
> if (!field_var) {
> @@ -3837,7 +3839,10 @@ static int check_synth_field(struct synth_event *event,
> && field->is_dynamic)
> return 0;
>
> - if (strstr(hist_field->type, "long[") && field->is_stack)
> + if (!!(hist_field->flags & HIST_FIELD_FL_STACKTRACE) != field->is_stack)
> + return -EINVAL;
> +
> + if (field->is_stack)
> return 0;
>
> if (strcmp(field->type, hist_field->type) != 0) {
> @@ -4360,7 +4365,8 @@ static int create_var_field(struct hist_trigger_data *hist_data,
> if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
> update_var_execname(hist_data->fields[val_idx]);
>
> - if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
> + if (!ret && !(hist_data->fields[val_idx]->flags & HIST_FIELD_FL_ALIAS) &&
> + hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
> hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
>
> return ret;
> @@ -5093,7 +5099,8 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
> if (hist_field->flags & HIST_FIELD_FL_VAR) {
> var_idx = hist_field->var.idx;
>
> - if (hist_field->flags & HIST_FIELD_FL_STRING) {
> + if (!(hist_field->flags & HIST_FIELD_FL_ALIAS) &&
> + hist_field->flags & HIST_FIELD_FL_STRING) {
> unsigned int str_start, var_str_idx, idx;
> char *str, *val_str;
> unsigned int size;
> --
> 2.53.0
>
--
Lee Jones
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-10-21 14:42 FAILED: patch "[PATCH] tracing/histograms: Reject non-stacktrace fields for" failed to apply to 6.1-stable tree gregkh
2026-10-21 15:37 ` [PATCH 6.1.y] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields Sasha Levin
2026-10-22 7:50 ` Lee Jones
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