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From: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
To: <linux@armlinux.org.uk>
Cc: <matthias.bgg@gmail.com>, <kstewart@linuxfoundation.org>,
	<allison@lohutok.net>, <lvqiang.huang@unisoc.com>,
	<gregkh@linuxfoundation.org>, <info@metux.net>,
	<tglx@linutronix.de>, <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-mediatek@lists.infradead.org>, <yj.chiang@mediatek.com>,
	<mark-pk.tsai@mediatek.com>, <alix.wu@mediatek.com>,
	<mike-sl.lin@mediatek.com>, <eddy.lin@mediatek.com>,
	<phil.chang@mediatek.com>
Subject: [PATCH] ARM: fix race in for_each_frame
Date: Tue, 12 Nov 2019 21:29:38 +0800	[thread overview]
Message-ID: <20191112132937.19335-1-mark-pk.tsai@mediatek.com> (raw)

The sv_pc, which is saved in the stack, may be an invalid address
if the target thread is running on another processor in the meantime.
It will cause kernel crash at `ldr r2, [sv_pc, #-4]`.

Check if sv_pc is valid before use it like unwind_frame in
arch/arm/kernel/unwind.c.

Signed-off-by: Mike-SL Lin <mike-sl.lin@mediatek.com>
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
 arch/arm/lib/backtrace.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S
index 582925238d65..84f06381bbfb 100644
--- a/arch/arm/lib/backtrace.S
+++ b/arch/arm/lib/backtrace.S
@@ -64,6 +64,11 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		sub	sv_pc, sv_pc, offset	@ Correct PC for prefetching
 		bic	sv_pc, sv_pc, mask	@ mask PC/LR for the mode
 
+		mov	r0, sv_pc
+		bl	kernel_text_address	@ check if sv_pc is valid
+		cmp	r0, #0			@ if sv_pc is not kernel text
+		beq	1006f			@ address, abort backtrace
+
 1003:		ldr	r2, [sv_pc, #-4]	@ if stmfd sp!, {args} exists,
 		ldr	r3, .Ldsi+4		@ adjust saved 'pc' back one
 		teq	r3, r2, lsr #11		@ instruction
-- 
2.18.0

WARNING: multiple messages have this Message-ID (diff)
From: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
To: <linux@armlinux.org.uk>
Cc: kstewart@linuxfoundation.org, mike-sl.lin@mediatek.com,
	alix.wu@mediatek.com, eddy.lin@mediatek.com,
	gregkh@linuxfoundation.org, yj.chiang@mediatek.com,
	phil.chang@mediatek.com, linux-kernel@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, mark-pk.tsai@mediatek.com,
	matthias.bgg@gmail.com, tglx@linutronix.de, info@metux.net,
	lvqiang.huang@unisoc.com, allison@lohutok.net
Subject: [PATCH] ARM: fix race in for_each_frame
Date: Tue, 12 Nov 2019 21:29:38 +0800	[thread overview]
Message-ID: <20191112132937.19335-1-mark-pk.tsai@mediatek.com> (raw)

The sv_pc, which is saved in the stack, may be an invalid address
if the target thread is running on another processor in the meantime.
It will cause kernel crash at `ldr r2, [sv_pc, #-4]`.

Check if sv_pc is valid before use it like unwind_frame in
arch/arm/kernel/unwind.c.

Signed-off-by: Mike-SL Lin <mike-sl.lin@mediatek.com>
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
 arch/arm/lib/backtrace.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S
index 582925238d65..84f06381bbfb 100644
--- a/arch/arm/lib/backtrace.S
+++ b/arch/arm/lib/backtrace.S
@@ -64,6 +64,11 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		sub	sv_pc, sv_pc, offset	@ Correct PC for prefetching
 		bic	sv_pc, sv_pc, mask	@ mask PC/LR for the mode
 
+		mov	r0, sv_pc
+		bl	kernel_text_address	@ check if sv_pc is valid
+		cmp	r0, #0			@ if sv_pc is not kernel text
+		beq	1006f			@ address, abort backtrace
+
 1003:		ldr	r2, [sv_pc, #-4]	@ if stmfd sp!, {args} exists,
 		ldr	r3, .Ldsi+4		@ adjust saved 'pc' back one
 		teq	r3, r2, lsr #11		@ instruction
-- 
2.18.0
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

WARNING: multiple messages have this Message-ID (diff)
From: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
To: <linux@armlinux.org.uk>
Cc: kstewart@linuxfoundation.org, mike-sl.lin@mediatek.com,
	alix.wu@mediatek.com, eddy.lin@mediatek.com,
	gregkh@linuxfoundation.org, yj.chiang@mediatek.com,
	phil.chang@mediatek.com, linux-kernel@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, mark-pk.tsai@mediatek.com,
	matthias.bgg@gmail.com, tglx@linutronix.de, info@metux.net,
	lvqiang.huang@unisoc.com, allison@lohutok.net
Subject: [PATCH] ARM: fix race in for_each_frame
Date: Tue, 12 Nov 2019 21:29:38 +0800	[thread overview]
Message-ID: <20191112132937.19335-1-mark-pk.tsai@mediatek.com> (raw)

The sv_pc, which is saved in the stack, may be an invalid address
if the target thread is running on another processor in the meantime.
It will cause kernel crash at `ldr r2, [sv_pc, #-4]`.

Check if sv_pc is valid before use it like unwind_frame in
arch/arm/kernel/unwind.c.

Signed-off-by: Mike-SL Lin <mike-sl.lin@mediatek.com>
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
 arch/arm/lib/backtrace.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S
index 582925238d65..84f06381bbfb 100644
--- a/arch/arm/lib/backtrace.S
+++ b/arch/arm/lib/backtrace.S
@@ -64,6 +64,11 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		sub	sv_pc, sv_pc, offset	@ Correct PC for prefetching
 		bic	sv_pc, sv_pc, mask	@ mask PC/LR for the mode
 
+		mov	r0, sv_pc
+		bl	kernel_text_address	@ check if sv_pc is valid
+		cmp	r0, #0			@ if sv_pc is not kernel text
+		beq	1006f			@ address, abort backtrace
+
 1003:		ldr	r2, [sv_pc, #-4]	@ if stmfd sp!, {args} exists,
 		ldr	r3, .Ldsi+4		@ adjust saved 'pc' back one
 		teq	r3, r2, lsr #11		@ instruction
-- 
2.18.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2019-11-12 13:31 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-12 13:29 Mark-PK Tsai [this message]
2019-11-12 13:29 ` [PATCH] ARM: fix race in for_each_frame Mark-PK Tsai
2019-11-12 13:29 ` Mark-PK Tsai
2019-11-12 14:14 ` 黄吕强 (Lvqiang Huang)
2019-11-12 15:20   ` Mark-PK Tsai
2019-11-12 15:20   ` Mark-PK Tsai
2019-11-12 15:20   ` Mark-PK Tsai
2019-11-12 14:14   ` 黄吕强 (Lvqiang Huang)
2019-11-12 14:14   ` 黄吕强 (Lvqiang Huang)
2019-11-12 14:35 ` 黄吕强 (Lvqiang Huang)
2019-11-12 14:35   ` 黄吕强 (Lvqiang Huang)
2019-11-12 14:35   ` 黄吕强 (Lvqiang Huang)
2019-11-13  3:25   ` Mark-PK Tsai
2019-11-13  3:25     ` Mark-PK Tsai
2019-11-13  3:25     ` Mark-PK Tsai

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