All of lore.kernel.org
 help / color / mirror / Atom feed
From: Wang Qing <wangqing@vivo.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	James Morse <james.morse@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	jinho lim <jordan.lim@samsung.com>, Wang Qing <wangqing@vivo.com>,
	Dave Martin <Dave.Martin@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: opensource.kernel@vivo.com
Subject: [PATCH 2/2] [V2 2/2]ARM64:fixed dump_backtrace() when task running on another cpu
Date: Mon, 13 Apr 2020 20:04:24 +0800	[thread overview]
Message-ID: <1586779466-4439-3-git-send-email-wangqing@vivo.com> (raw)
In-Reply-To: <1586779466-4439-1-git-send-email-wangqing@vivo.com>

We cannot get FP and PC when the task is running on another CPU,
task->thread.cpu_context is the last time the task was switched out,
it's better to give a reminder than to provide wrong information.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 arch/arm64/kernel/traps.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index cf402be..831b8fd 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -106,6 +106,13 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		start_backtrace(&frame,
 				(unsigned long)__builtin_frame_address(0),
 				(unsigned long)dump_backtrace);
+	} else if (task_running_oncpu(tsk)) {
+		/*
+		 * The task is running in another cpu, we cannot get it.
+		 */
+		pr_warn("tsk: %s is running in CPU%d, Don't call trace!\n",
+			tsk->comm, task_cpu(tsk));
+		return;
 	} else {
 		/*
 		 * task blocked in __switch_to
-- 
2.7.4


WARNING: multiple messages have this Message-ID (diff)
From: Wang Qing <wangqing@vivo.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	James Morse <james.morse@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	jinho lim <jordan.lim@samsung.com>, Wang Qing <wangqing@vivo.com>,
	Dave Martin <Dave.Martin@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: opensource.kernel@vivo.com
Subject: [PATCH 2/2] [V2 2/2]ARM64:fixed dump_backtrace() when task running on another cpu
Date: Mon, 13 Apr 2020 20:04:24 +0800	[thread overview]
Message-ID: <1586779466-4439-3-git-send-email-wangqing@vivo.com> (raw)
In-Reply-To: <1586779466-4439-1-git-send-email-wangqing@vivo.com>

We cannot get FP and PC when the task is running on another CPU,
task->thread.cpu_context is the last time the task was switched out,
it's better to give a reminder than to provide wrong information.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 arch/arm64/kernel/traps.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index cf402be..831b8fd 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -106,6 +106,13 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		start_backtrace(&frame,
 				(unsigned long)__builtin_frame_address(0),
 				(unsigned long)dump_backtrace);
+	} else if (task_running_oncpu(tsk)) {
+		/*
+		 * The task is running in another cpu, we cannot get it.
+		 */
+		pr_warn("tsk: %s is running in CPU%d, Don't call trace!\n",
+			tsk->comm, task_cpu(tsk));
+		return;
 	} else {
 		/*
 		 * task blocked in __switch_to
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-04-13 12:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-13 12:04 [PATCH 0/2] fixed dump_backtrace() when task running on another cpu Wang Qing
2020-04-13 12:04 ` Wang Qing
2020-04-13 12:04 ` [PATCH 1/2] [V2 1/2]sched:add task_running_oncpu Wang Qing
2020-04-13 12:04   ` Wang Qing
2020-04-14  7:20   ` Vincent Guittot
2020-04-14  7:20     ` Vincent Guittot
2020-04-14 10:05     ` Peter Zijlstra
2020-04-14 10:05       ` Peter Zijlstra
2020-04-14  9:47   ` Wang Qing
2020-04-15  8:34   ` Wang Qing
2020-04-15  8:34     ` Wang Qing
2020-04-13 12:04 ` Wang Qing [this message]
2020-04-13 12:04   ` [PATCH 2/2] [V2 2/2]ARM64:fixed dump_backtrace() when task running on another cpu Wang Qing

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1586779466-4439-3-git-send-email-wangqing@vivo.com \
    --to=wangqing@vivo.com \
    --cc=Dave.Martin@arm.com \
    --cc=bsegall@google.com \
    --cc=catalin.marinas@arm.com \
    --cc=dietmar.eggemann@arm.com \
    --cc=ebiederm@xmission.com \
    --cc=james.morse@arm.com \
    --cc=jordan.lim@samsung.com \
    --cc=juri.lelli@redhat.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=mgorman@suse.de \
    --cc=mingo@redhat.com \
    --cc=opensource.kernel@vivo.com \
    --cc=peterz@infradead.org \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --cc=vincent.guittot@linaro.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.