From: Wang Qing <wangqing@vivo.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
James Morse <james.morse@arm.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Thomas Gleixner <tglx@linutronix.de>,
Wang Qing <wangqing@vivo.com>, jinho lim <jordan.lim@samsung.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] ARM64: fixed dump_backtrace() when task running on another cpu
Date: Thu, 9 Apr 2020 17:38:16 +0800 [thread overview]
Message-ID: <1586425106-7369-1-git-send-email-wangqing@vivo.com> (raw)
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 | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index cf402be..c04e3e8 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -106,6 +106,14 @@ 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 (tsk->on_cpu) {
+ /*
+ * The task is running in another cpu, so the call stack
+ * is changing and we cannot get it.
+ */
+ pr_warn("tsk: %s is running in CPU%d, Don't call trace!\n",
+ tsk->comm, tsk->cpu);
+ return;
} else {
/*
* task blocked in __switch_to
--
2.7.4
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next reply other threads:[~2020-04-09 9:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 9:38 Wang Qing [this message]
2020-04-09 10:40 ` [PATCH] ARM64: fixed dump_backtrace() when task running on another cpu Mark Rutland
2020-04-13 9:23 ` Wang Qing
2020-04-14 12:54 ` [PATCH] " Mark Rutland
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