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=1792678143; b=lI8+ngEHt/bc/0xIw/QIaFgD31/j3ZT39Fa+xfwtKnTbn9pks3vIG2syYSwt3rWx7JYB UQ3L5QdC/TqxMY9arlu0uG15IiYJ9thVZ4BnlHWErvNJCudVB/vrMcD65iZYoW21ME4iw hX0M7wEmOfbZo7dWq6pisCmQ11iyA28/EkNyfe4kvpDdIEiAGiCrBmdbRVGpYikFFoWA0 7acw6cZZg5e2DoAaSadP4c5FbvZFHVhDW2aiZNPTXIiEY+FB6EiIQQg/zHyIhonQRrNkw Q/srpXUYD2bmG3S86a2B0VNHr8uoQG2jFh4VLud/i3kjVCB32VE9DzdZ4DPUs1xDVLA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792678143; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=q45kTUHwAqCJNhX1DNdsP+3hLbDNU9+IBL03bbxOVlU=; b=UC1Yc8WAND+nVNBKHAIB+lrL4Ej44WKbeDm0G9aU/BlR6HUHHI+Gf7hqRTxOfwuEdqyo zIX+F6FscC4CgwRlhKhr5xx/7DRMRneR8y6U4fBv9VoBJ8waI4I6PK/QWPo+rO8yeybwD ixKlCM4NrRIU1Wg0UTm/8mFJjRHqeZs0TmDDi6zdJBuNgKSG4IkAGlSf/+QglHq0r4qum fn36qD81aOHJxVFKhA/1uqhk0BlNkENvCB1XaFaLl5wjtHpC9whefSD/2qauob9oM7hgk aYkQLU7DByvkWtHnFUa8w/yM0moA5ZEUotlpMxrdC7HK0uQdX07628FXSjTrhn7MYBA== 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="VlUdXL8/"; 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 93D28606A31A for ; Thu, 22 Oct 2026 14:09:03 +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=VlUdXL8/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id A50B61F000C2; Thu, 22 Oct 2026 14:09:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792678143; bh=q45kTUHwAqCJNhX1DNdsP+3hLbDNU9+IBL03bbxOVlU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VlUdXL8/XVoizo+jYjFmvlOQCj42WQflIvk+Dmrt4t6uHnoUmBR4ilg8k1js6wvcq r5UWhaP6yD7HLnoiXEP7UNXgotTycb5NDNpACmPMFNyT2knp2LWw/Ex8CMqasTQI9H XUCjobcY4ZQq5MBkgMC01DWv0ShLcz5ur25VadulLVsUZHWfO1s9DPcr5L4aafrgS6 IKdDPZgNDtNd+CPkeVJiB5lNE29uJ+rNL4wpzeTm3KqwkDbP/YeghfwEOOr7A0hycv 3zSLau1qRxTOMfZX9YiYiViNAdL9HXgQgjZEet6TVs416aH+z3HgKAwEnZpM6SEnix O1sEtkdtg23+w== From: Sasha Levin To: stable@vger.kernel.org Cc: Tom Zanussi , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.12.y 1/4] tracing: Fix fully-qualified variable reference printing in histograms Date: Thu, 22 Oct 2026 10:08:58 -0400 Message-ID: <20261022140848.1513845-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102122-sandy-lazy-aa40@gregkh> References: <2026102122-sandy-lazy-aa40@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: Tom Zanussi [ Upstream commit 9236eebd138aa2753f7b30fc6cee7b7202841247 ] The syntax for fully-qualified variable references in histograms is subsys.event.$var, which is parsed correctly, but not displayed correctly when printing a histogram spec. The current code puts the $ reference at the beginning of the fully-qualified variable name i.e. $subsys.event.var, which is incorrect. Before: trigger info: hist:keys=next_comm:vals=hitcount:wakeup_lat=common_timestamp.usecs-$sched.sched_wakeup.ts0: ... After: trigger info: hist:keys=next_comm:vals=hitcount:wakeup_lat=common_timestamp.usecs-sched.sched_wakeup.$ts0: ... Link: https://patch.msgid.link/5dee9a86d062a4dd68c2214f3d90ac93811e1951.1776112478.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google) Stable-dep-of: a0777b9e5315 ("tracing: Fix NULL dereference when copying keys for a field variable") Signed-off-by: Sasha Levin --- kernel/trace/trace_events_hist.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index eaf6084d65149..31563c47bb8d9 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1342,9 +1342,12 @@ static const char *hist_field_name(struct hist_field *field, field->flags & HIST_FIELD_FL_VAR_REF) { if (field->system) { static char full_name[MAX_FILTER_STR_VAL]; + static char *fmt; int len; - len = snprintf(full_name, sizeof(full_name), "%s.%s.%s", + fmt = field->flags & HIST_FIELD_FL_VAR_REF ? "%s.%s.$%s" : "%s.%s.%s"; + + len = snprintf(full_name, sizeof(full_name), fmt, field->system, field->event_name, field->name); if (len < sizeof(full_name)) @@ -1724,9 +1727,10 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) static void expr_field_str(struct hist_field *field, char *expr) { - if (field->flags & HIST_FIELD_FL_VAR_REF) - strcat(expr, "$"); - else if (field->flags & HIST_FIELD_FL_CONST) { + if (field->flags & HIST_FIELD_FL_VAR_REF) { + if (!field->system) + strcat(expr, "$"); + } else if (field->flags & HIST_FIELD_FL_CONST) { char str[HIST_CONST_DIGITS_MAX]; snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant); @@ -6139,7 +6143,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) else if (field_name) { if (hist_field->flags & HIST_FIELD_FL_VAR_REF || hist_field->flags & HIST_FIELD_FL_ALIAS) - seq_putc(m, '$'); + if (!hist_field->system) + seq_putc(m, '$'); seq_printf(m, "%s", field_name); } else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP) seq_puts(m, "common_timestamp"); -- 2.53.0