From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0B37D13DDDD; Thu, 11 Apr 2024 09:59:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712829593; cv=none; b=nox96adl85HBxgY2gisMXYAY8G6uog8jHYZ1sSiQqEWMhqQB2ZS1NoHt3ZAVK4267k0WkpBT8p8n2DyRN5K1M/diRhOUAwS9vA41/fdQKvQpYmj5eQRUHfQN+mG5O3qpXM8tTPs5Rj74zln5nHrhBbnpXdBPWp3xysZ3duDdlH0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712829593; c=relaxed/simple; bh=kQMK0nUIAothLCUvFWbs4BueDFPzk6ScDOSK37Qd0pQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cUOR6gnRBqyZYrUylFaF14C4JPee7VqAVounz0WZeXtItSYWXprwbbPXNwNErquVayKQG57ybfwSLGDTjpqRLrjclHaKMyohCFJ+cPnH8jYu/mpSycgNndFCxCWIlpxX96uInQw9CXa8Vx8DaDPUOsK6eC3Mel/gxfXSeoydS8c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZnT3DKYk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ZnT3DKYk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88392C433C7; Thu, 11 Apr 2024 09:59:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712829592; bh=kQMK0nUIAothLCUvFWbs4BueDFPzk6ScDOSK37Qd0pQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZnT3DKYk9gRHE+ia156No7bjJTS/dq0Sjd1ufwb4IdKrpks9VQqxktDbNgLwxFR5B gkDHYwo/Qj5uzPi7HZdB+FbwuX00gd1ciAsHPTcRYBmK3EF7UMAsFomrKcMnXPXx0a dEB2bvOJQkV83t0CTCZiwmJDeVaoDXPMlcvUfV+Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Anna-Maria Gleixner , Thomas Gleixner , fweisbec@gmail.com, peterz@infradead.org, Steven Rostedt , Sasha Levin Subject: [PATCH 4.19 005/175] timer/trace: Improve timer tracing Date: Thu, 11 Apr 2024 11:53:48 +0200 Message-ID: <20240411095419.700907917@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240411095419.532012976@linuxfoundation.org> References: <20240411095419.532012976@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Anna-Maria Gleixner [ Upstream commit f28d3d5346e97e60c81f933ac89ccf015430e5cf ] Timers are added to the timer wheel off by one. This is required in case a timer is queued directly before incrementing jiffies to prevent early timer expiry. When reading a timer trace and relying only on the expiry time of the timer in the timer_start trace point and on the now in the timer_expiry_entry trace point, it seems that the timer fires late. With the current timer_expiry_entry trace point information only now=jiffies is printed but not the value of base->clk. This makes it impossible to draw a conclusion to the index of base->clk and makes it impossible to examine timer problems without additional trace points. Therefore add the base->clk value to the timer_expire_entry trace point, to be able to calculate the index the timer base is located at during collecting expired timers. Signed-off-by: Anna-Maria Gleixner Signed-off-by: Thomas Gleixner Cc: fweisbec@gmail.com Cc: peterz@infradead.org Cc: Steven Rostedt Link: https://lkml.kernel.org/r/20190321120921.16463-5-anna-maria@linutronix.de Stable-dep-of: 0f7352557a35 ("wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach") Signed-off-by: Sasha Levin --- include/trace/events/timer.h | 11 +++++++---- kernel/time/timer.c | 17 +++++++++++++---- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h index 8f6240854e28f..295517f109d71 100644 --- a/include/trace/events/timer.h +++ b/include/trace/events/timer.h @@ -89,24 +89,27 @@ TRACE_EVENT(timer_start, */ TRACE_EVENT(timer_expire_entry, - TP_PROTO(struct timer_list *timer), + TP_PROTO(struct timer_list *timer, unsigned long baseclk), - TP_ARGS(timer), + TP_ARGS(timer, baseclk), TP_STRUCT__entry( __field( void *, timer ) __field( unsigned long, now ) __field( void *, function) + __field( unsigned long, baseclk ) ), TP_fast_assign( __entry->timer = timer; __entry->now = jiffies; __entry->function = timer->function; + __entry->baseclk = baseclk; ), - TP_printk("timer=%p function=%ps now=%lu", - __entry->timer, __entry->function, __entry->now) + TP_printk("timer=%p function=%ps now=%lu baseclk=%lu", + __entry->timer, __entry->function, __entry->now, + __entry->baseclk) ); /** diff --git a/kernel/time/timer.c b/kernel/time/timer.c index a6e88d9bb931c..140662c2b41e1 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1311,7 +1311,9 @@ int del_timer_sync(struct timer_list *timer) EXPORT_SYMBOL(del_timer_sync); #endif -static void call_timer_fn(struct timer_list *timer, void (*fn)(struct timer_list *)) +static void call_timer_fn(struct timer_list *timer, + void (*fn)(struct timer_list *), + unsigned long baseclk) { int count = preempt_count(); @@ -1334,7 +1336,7 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(struct timer_list */ lock_map_acquire(&lockdep_map); - trace_timer_expire_entry(timer); + trace_timer_expire_entry(timer, baseclk); fn(timer); trace_timer_expire_exit(timer); @@ -1355,6 +1357,13 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(struct timer_list static void expire_timers(struct timer_base *base, struct hlist_head *head) { + /* + * This value is required only for tracing. base->clk was + * incremented directly before expire_timers was called. But expiry + * is related to the old base->clk value. + */ + unsigned long baseclk = base->clk - 1; + while (!hlist_empty(head)) { struct timer_list *timer; void (*fn)(struct timer_list *); @@ -1368,11 +1377,11 @@ static void expire_timers(struct timer_base *base, struct hlist_head *head) if (timer->flags & TIMER_IRQSAFE) { raw_spin_unlock(&base->lock); - call_timer_fn(timer, fn); + call_timer_fn(timer, fn, baseclk); raw_spin_lock(&base->lock); } else { raw_spin_unlock_irq(&base->lock); - call_timer_fn(timer, fn); + call_timer_fn(timer, fn, baseclk); raw_spin_lock_irq(&base->lock); } } -- 2.43.0