From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "louis.wang" <liang26812@gmail.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
Sasha Levin <sashal@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.4 04/23] ARM: 9066/1: ftrace: pause/unpause function graph tracer in cpu_suspend()
Date: Wed, 12 May 2021 14:03:48 -0400 [thread overview]
Message-ID: <20210512180408.665338-4-sashal@kernel.org> (raw)
In-Reply-To: <20210512180408.665338-1-sashal@kernel.org>
From: "louis.wang" <liang26812@gmail.com>
[ Upstream commit 8252ca87c7a2111502ee13994956f8c309faad7f ]
Enabling function_graph tracer on ARM causes kernel panic, because the
function graph tracer updates the "return address" of a function in order
to insert a trace callback on function exit, it saves the function's
original return address in a return trace stack, but cpu_suspend() may not
return through the normal return path.
cpu_suspend() will resume directly via the cpu_resume path, but the return
trace stack has been set-up by the subfunctions of cpu_suspend(), which
makes the "return address" inconsistent with cpu_suspend().
This patch refers to Commit de818bd4522c40ea02a81b387d2fa86f989c9623
("arm64: kernel: pause/unpause function graph tracer in cpu_suspend()"),
fixes the issue by pausing/resuming the function graph tracer on the thread
executing cpu_suspend(), so that the function graph tracer state is kept
consistent across functions that enter power down states and never return
by effectively disabling graph tracer while they are executing.
Signed-off-by: louis.wang <liang26812@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/kernel/suspend.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
index d08099269e35..e126386fb78a 100644
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mm_types.h>
@@ -26,6 +27,13 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
if (!idmap_pgd)
return -EINVAL;
+ /*
+ * Function graph tracer state gets incosistent when the kernel
+ * calls functions that never return (aka suspend finishers) hence
+ * disable graph tracing during their execution.
+ */
+ pause_graph_tracing();
+
/*
* Provide a temporary page table with an identity mapping for
* the MMU-enable code, required for resuming. On successful
@@ -33,6 +41,9 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
* back to the correct page tables.
*/
ret = __cpu_suspend(arg, fn, __mpidr);
+
+ unpause_graph_tracing();
+
if (ret == 0) {
cpu_switch_mm(mm->pgd, mm);
local_flush_bp_all();
@@ -46,7 +57,13 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
{
u32 __mpidr = cpu_logical_map(smp_processor_id());
- return __cpu_suspend(arg, fn, __mpidr);
+ int ret;
+
+ pause_graph_tracing();
+ ret = __cpu_suspend(arg, fn, __mpidr);
+ unpause_graph_tracing();
+
+ return ret;
}
#define idmap_pgd NULL
#endif
--
2.30.2
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next prev parent reply other threads:[~2021-05-12 18:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 18:03 [PATCH AUTOSEL 5.4 01/23] ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6 Sasha Levin
2021-05-12 18:03 ` [PATCH AUTOSEL 5.4 02/23] PCI: thunder: Fix compile testing Sasha Levin
2021-05-12 18:03 ` Sasha Levin [this message]
2021-05-12 18:03 ` [PATCH AUTOSEL 5.4 11/23] ARM: 9075/1: kernel: Fix interrupted SMC calls Sasha Levin
2021-05-12 18:04 ` [PATCH AUTOSEL 5.4 23/23] net: stmmac: Do not enable RX FIFO overflow interrupts Sasha Levin
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