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=1792676565; b=t4XURo2SwG5OYeTtePUe+n55wSuGh5Wf3duG1qNB9AuHiL0gafHSsOQ/FZ6hIuVSvJRQ oxAKWyBhtFuzjtSUoXrrPAAH4JQAN+d8X396Ipp8ET5np7Q4DKQqW8kb0EaFRBXO3t2Zd 4Mc4FofrMCqqhg82vCPIcClB1drEXKe8Mn2efP/MUHEJB92419TRMamNemSV7zAjXbCEz 2lRCRY3a3GZM/APPHcxuSuCYmn3mCD/wFnROrW3KT/7ULIba0LghiVVFUgq+cyAGAyVpd 3dj+Sh2MM+QQINPH61lumc6a0ukVM6w+0W+zKdIddJ9omNBX+YO9/5l7tXroCuNmB+Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792676565; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=YmIclGySJ9hBWuStNof5v4e1D7qYVK7xk32MmCNoaC0=; b=INr0oD2h0n148l5rw/wjXf7LgzWORwJLEO155RB4S13VgNfMYqVQnTZBiSfUmmKUoDUS PpyM+E2cuNKTuLm9GWDZWxIwLFMjEz4Yi6ZgwR0TLJMYnOSQQ32JkIwFvmjcsBgPFG2AS 6pkSH9XXz9/QRIJ0HhoGmbD1AACeqbr0+R5tjVQk2XUHq9Rgl/CEfgOyEcANQcsLdAmm8 gcGkLjuuvDGyRVi4EDexRJodQ1UlRGKMR5QYIDqLTU40KoWKDL3Ol5ELsydRz0Sp1/F0i 4hXksnNa6gP+eQL4sOsc3wMCcMm/jn+OeFoRcp34XgdWJxBUa4gsCPUjJMVr7ZdIVzA== 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=mrvnOOSv; 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 17837606A323 for ; Thu, 22 Oct 2026 13:42:44 +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=mrvnOOSv Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DF961F000C3; Thu, 22 Oct 2026 13:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792676564; bh=YmIclGySJ9hBWuStNof5v4e1D7qYVK7xk32MmCNoaC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mrvnOOSvqKwckGXiWojYOkSaWpd5PfidQsI48izPA47siyl1lZl9rD2qonS5pTLFJ /WPfWtd91nUEQ4Cx1sefV/Ebk+/2srPQSMjBdn6KtGCNsvupkfvUArS9fjA7mhbRA/ nR+A7OG4bqtyba8q6OtIrXZJEOy1RSbPF+RG0HUgMRSqwMJElKn/oHPBIF6FeZ9G/m Vxb2+V3eVo6CuDGDcZxcl3i5vJvQ7Kt0Wb+bksZYeU8uMqMUbDSuUWyuoH2JGr4hWf Whmzc9lghjT4RpgWlhD7pFuZEzxtSETUfKU63f/XikwVhAHW55KXuwogNJ/UPZdv0d h7jiJpWtb8gTg== From: Sasha Levin To: stable@vger.kernel.org Cc: Tom Zanussi , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.18.y 1/4] tracing: Fix fully-qualified variable reference printing in histograms Date: Thu, 22 Oct 2026 09:42:39 -0400 Message-ID: <20261022134230.1444063-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102122-spinster-handler-2d56@gregkh> References: <2026102122-spinster-handler-2d56@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.$ts0: ... Link: https://patch.msgid.link/5dee9a86d062a4dd68c2214f3d90ac93811e1951.1776112478.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google) Stable-dep-of: a0777b9e5315 ("tracing: Fix NULL dereference when copying keys for a field variable") Signed-off-by: Sasha Levin --- kernel/trace/trace_events_hist.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 20d23a08b5b8b..dab2b3dc176b9 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1355,9 +1355,12 @@ static const char *hist_field_name(struct hist_field *field, field->flags & HIST_FIELD_FL_VAR_REF) { if (field->system) { static char full_name[MAX_FILTER_STR_VAL]; + static char *fmt; int len; - len = snprintf(full_name, sizeof(full_name), "%s.%s.%s", + fmt = field->flags & HIST_FIELD_FL_VAR_REF ? "%s.%s.$%s" : "%s.%s.%s"; + + len = snprintf(full_name, sizeof(full_name), fmt, field->system, field->event_name, field->name); if (len < sizeof(full_name)) @@ -1734,9 +1737,10 @@ 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); @@ -6167,7 +6171,8 @@ 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