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=1792774253; b=pALXrdzWkVSpfnoWaUf74Bzq6KI0AS+9SX3LWvHMf7+OC/5SfNT5afa2GumOTjj9uV7y czw0YDFg/S94ti+vdVz/YMskgneBz53yS8FhqaXxvw7eVAkUqhY220mjQ0CPQsZcDR/xx PK8MwZWavq8X1tCsFPERDOwknOgMSjn6plBTva7I7eIM5q2bYjm/1ZzfYFj4LTEysRj26 BzV9haZg/mFgrbPw02/+G2JlzMqiYwCb9ebzYfkRtDRTCYkEyjll4ouoFSnKvu+XD/HQx gFtFUY59oAXMMqMuo6IDUWYZ9U4GSU0gT5d/uYxvZUK+CxwqDecqtU/F9VNvHdgiKjw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774253; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=Zd5L/oRzP1wg1gCNP4Fs3twhQBNTWi8+eqtm354A3a0=; b=pD7MR4UWdZCtnk3tc41M2GvnfiVD4R5rx4QXGsAxHAdTLSCHcGkNeDAB9nE5J2hGyKO3 r+kvCNtQ6jSmAmcISp9EmcfknWFxv9HLg1RkXseQrfY28+ClAYHTbIV0jaWIMKBw3Ncya GciPAIS7+gPe51fbKUqDfr93nGpTuh+Ki+w53Hi8XUb2v1xAQ1JhNpAnV8YbfIc8+9lsA u37TYdJ7f21Vp5FuoziS/dqgHIudrEcPIAniTShosc8P1oFyTFhBNhqONbINt+GeleWWA OKAaT9VQYLIx773rjQSuJ2yCqoq4WThBQi1pelRFBkVxJrqy/82wQnQ67Hv+gN3bqyg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=fga+KQpp; 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 E96C7606A328; Fri, 23 Oct 2026 16:50:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=fga+KQpp Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F69E1F01825; Fri, 23 Oct 2026 16:50:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774252; bh=Zd5L/oRzP1wg1gCNP4Fs3twhQBNTWi8+eqtm354A3a0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fga+KQppwYL5l9OuPRVwtx0CZMBVXJh++WsR6Nd81Htd+c3F++RQ1/AYUsYM2U77C arHAzBWWLBZp17DW08RXfSqNkKgBsz7crAbNmA9D+lLAQDUqi3Ngfbm2il9MWS0e3I dZRGl/v3Hps8ph5yLls9GSjiViWhGbWrMlKKpw1U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tom Zanussi , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.18 171/193] tracing: Fix fully-qualified variable reference printing in histograms Date: Fri, 23 Oct 2026 18:37:28 +0200 Message-ID: <20261023163718.260677513@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163714.201276352@linuxfoundation.org> References: <20261023163714.201276352@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ 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.$ts0: ... Link: https://patch.msgid.link/5dee9a86d062a4dd68c2214f3d90ac93811e1951.1776112478.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google) Stable-dep-of: a0777b9e5315 ("tracing: Fix NULL dereference when copying keys for a field variable") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1355,9 +1355,12 @@ static const char *hist_field_name(struc field->flags & HIST_FIELD_FL_VAR_REF) { if (field->system) { static char full_name[MAX_FILTER_STR_VAL]; + static char *fmt; int len; - len = snprintf(full_name, sizeof(full_name), "%s.%s.%s", + fmt = field->flags & HIST_FIELD_FL_VAR_REF ? "%s.%s.$%s" : "%s.%s.%s"; + + len = snprintf(full_name, sizeof(full_name), fmt, field->system, field->event_name, field->name); if (len < sizeof(full_name)) @@ -1734,9 +1737,10 @@ static const char *get_hist_field_flags( 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); @@ -6167,7 +6171,8 @@ static void hist_field_print(struct seq_ 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");