From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792597039; b=p+poqNDw2cqUeYANUAsTTcohMt+xkSGugIixpez7cvBoAHDVHjyprMP3yoQH3xC+duNU vBn9ZIJCzPjWHtMkJu3YX/o2EcqPbPI04efYwRfOa6ZDjZOqZR9o8xsuZtUTIwxWInIw1 dRil2km/tyaY5mj92NC++1jVP2tjgoGFFuFJCxvfqzr48qQNd7KC4q6kqRVJLurSMAirj 06pGqA2DhPiDSNyLMkv4PU2YtqBnivznYUNRFIVgN0jcKZhVG83L565OGeS9CkEg7IkU5 xBTl1+xya0vvNIY8Fq4IOIBydHe7nodPwYCgxUfp+qjR8t0EEaPTfWmAcZ26Pex0YSA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792597039; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=/TAFCYmY1d6h1533UQpOgy7mkXVJ98JtODw5xZZ2twk=; b=nqqhpfRAy1TkgP3DCPyLykrHHxe6HFMKQLYzuQ6YcA/oePcf1C9R6qgQV3icXmUluVF3 63eSox3t9GMBDn7Pt0Jqhzvo5/cgs5nuYHpRKq2QnpkmwJyE/x+7RkfondYzEJrZ/L5+K KEBxpzMqsEJY4Dnv46MH10eYShFlB5yBX9MVgo4hqLioALa8OXawH/MaWGQ+yjfqaxTYG P2OTtUuwefqyTq3uFdBHCalp+8mRTWeVMvJTFeOXU+S746+UCjgbtou+qDBKUbO0W6oTh x0+NNfh0BWOfZgqKOuVY5kzRseLejzxyk19PpcRA8ec1vbYO9wWfBNdefSUcU26kBSg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=IlKLCenB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 657B0606A31A for ; Wed, 21 Oct 2026 15:37:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=IlKLCenB Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D5AD1F000C2; Wed, 21 Oct 2026 15:37:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792597039; bh=/TAFCYmY1d6h1533UQpOgy7mkXVJ98JtODw5xZZ2twk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IlKLCenBs0WwOlA3FB3Q+h0uzYNT7cwpbK7DaSbolud21/UebZz4864CTTYVPUqW3 Sq/pNaS7BuOmKnor8NJZwmkOcrDwGNVsDo75+7loHtKeIZvDWGnHPunrUsUbhf+EOZ g5DOsVg7IdMFr7TQZqgECZCY1wsxnrh7gt+xooDdgnCx0w1LBkx/m7vJBgFKzcoYCg 5rvmCmaiRzMZYz+mfSfmUFhyWgf1Grj4nXn1fAsjGKOggN6Vn5ZRILs+7cIpGyF/oZ v2Aa6nBQrITkBauoLQlSWu50JyMQz4sANL0JzJCgdUPlc6kLh1tb86mq5FSWXuLWI3 iaSKlGRwNnokQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Lee Jones , "Masami Hiramatsu (Google)" , Steven Rostedt , Sasha Levin Subject: [PATCH 6.1.y] tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields Date: Wed, 21 Oct 2026 11:37:17 -0400 Message-ID: <20261021153403.303474-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102125-surely-nastily-2d17@gregkh> References: <2026102125-surely-nastily-2d17@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Lee Jones [ 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 Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt [ sashal: Retained string-only buffer conditions because histogram stacktrace-variable support is absent. ] Signed-off-by: Sasha Levin --- 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