From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EA88D3DB33C; Tue, 13 Oct 2026 11:38:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791891541; cv=none; b=DiA2AzjhDgqQ3BIonqC3MRY+ED5IbINJhaGjgRdXIIWhL1yhNesDr5XuyTaa6Ad3rPq4xwmVfP/+0d1vTAWTMLz09lRnAyby8OxEIjY83rSKiz9VAIhCWJzshfk/VEleqjD6egYD9c4GAO2mjMlLnEv27KfOVU7ZVCS/olu0QyE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791891541; c=relaxed/simple; bh=F3jbrUon50I/esfgt38aY5mZa678/5mAa/00VYW7/nc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BALNjAeggFBuFFeVxi5Tv+DcOHG0dOIAt7+3knOe6eiElfJc67UsURc5z5zZ56UllV7LDXgro1ga5xXp6mN3a5oPmbNeb61fUVmVTxho14SFiimaHpESsp2fAiCDnj9jWSs5oyGHGO9I0FDNoxO9kmxuCQs/JsSPU0kXkixasxs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BLyRBUQx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BLyRBUQx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D5421F000FF; Tue, 13 Oct 2026 11:38:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791891539; bh=iM7Kn1upRKCYgX3my+5a9iEmzXraOMK8a7ELFfehbz4=; h=From:To:Cc:Subject:Date; b=BLyRBUQxmYZGUAeaHFZEzWN0WXTwLON5T6iRtekbZ28LOLeR9AvTb8QnRRsdR8UrL 796ejjZfccuD7wK8vjH6e0Boe62b7KWRJAiNsO2+/iFFqlivG90MLbN+zX+XtyeNxw BSOsSoNeyqlzfthkBIEKIsy42+fN+u5Y542Fwl+ZhuPt370uFubIHQvZTVro25+q3G tRsN7O6rWjrxm6G1c9oVjlNalmF8GBsO+FEPP10IVtM0IHNoAr6fGG4YbFEdoI54UX 5ecw6Ce9ekUpN7fcRiYXc8kTPpNqGYgksodQGALu3/elqjmoNWNVpMzBLY+7FwgNJq Y3OIPV+5Y3Cfw== From: Lee Jones To: lee@kernel.org, Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: stable@vger.kernel.org Subject: [PATCH v2] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields Date: Tue, 13 Oct 2026 11:24:48 +0000 Message-ID: <20261013112449.1006088-1-lee@kernel.org> X-Mailer: git-send-email 2.56.0.385.gd3acb90ef8-goog Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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(). Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces") Cc: stable@vger.kernel.org Signed-off-by: Lee Jones --- v1 -> v2: - Check HIST_FIELD_FL_STACKTRACE instead of strstr(hist_field->type, "long[") so __bitmask() and __rel_bitmask() fields are also rejected. - Propagate HIST_FIELD_FL_STACKTRACE to variable references and field variables, whilst excluding variable aliases from per-element stacktrace capture. 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 8af97fd4ee2d..d8864b3165d2 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; -- 2.56.0.385.gd3acb90ef8-goog