[PATCH v2 1/2] x86: corruption-check: Passing memory_corruption_check to command line causes panic

[PATCH v2 1/2] x86: corruption-check: Passing memory_corruption_check to command line causes panic

[zhe.he]

From: He Zhe <zhe.he@windriver.com>

memory_corruption_check[{_period|_size}]'s handlers do not check input
argument before passing it to kstrtoul or simple_strtoull. The argument
would be a NULL pointer if each of the kernel parameters, without its
value, is set in command line and thus cause the following panic.

PANIC: early exception 0xe3 IP 10:ffffffff73587c22 error 0 cr2 0x0
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #2
[    0.000000] RIP: 0010:kstrtoull+0x2/0x10
...
[    0.000000] Call Trace
[    0.000000]  ? set_corruption_check+0x21/0x49
[    0.000000]  ? do_early_param+0x4d/0x82
[    0.000000]  ? parse_args+0x212/0x330
[    0.000000]  ? rdinit_setup+0x26/0x26
[    0.000000]  ? parse_early_options+0x20/0x23
[    0.000000]  ? rdinit_setup+0x26/0x26
[    0.000000]  ? parse_early_param+0x2d/0x39
[    0.000000]  ? setup_arch+0x2f7/0xbf4
[    0.000000]  ? start_kernel+0x5e/0x4c2
[    0.000000]  ? load_ucode_bsp+0x113/0x12f
[    0.000000]  ? secondary_startup_64+0xa5/0xb0

This patch adds checks to prevent the panic.

Cc: stable@vger.kernel.org
Signed-off-by: He Zhe <zhe.he@windriver.com>
---
v2:
- Split out printk cleanups
- Add cc to stable@vger.kernel.org
- Use more meaningful error message

 arch/x86/kernel/check.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c
index 3339942..cc8258a 100644
--- a/arch/x86/kernel/check.c
+++ b/arch/x86/kernel/check.c
@@ -31,6 +31,11 @@ static __init int set_corruption_check(char *arg)
 	ssize_t ret;
 	unsigned long val;
 
+	if (!arg) {
+		pr_err("memory_corruption_check config string not provided\n");
+		return -EINVAL;
+	}
+
 	ret = kstrtoul(arg, 10, &val);
 	if (ret)
 		return ret;
@@ -45,6 +50,11 @@ static __init int set_corruption_check_period(char *arg)
 	ssize_t ret;
 	unsigned long val;
 
+	if (!arg) {
+		pr_err("memory_corruption_check_period config string not provided\n");
+		return -EINVAL;
+	}
+
 	ret = kstrtoul(arg, 10, &val);
 	if (ret)
 		return ret;
@@ -59,6 +69,11 @@ static __init int set_corruption_check_size(char *arg)
 	char *end;
 	unsigned size;
 
+	if (!arg) {
+		pr_err("memory_corruption_check_size config string not provided\n");
+		return -EINVAL;
+	}
+
 	size = memparse(arg, &end);
 
 	if (*end == '\0')
-- 
2.7.4

[PATCH v2 2/2] x86: corruption-check: Change printk to the right fashion

[zhe.he]

From: He Zhe <zhe.he@windriver.com>

pr_* is preferred according to scripts/checkpatch.pl.

Signed-off-by: He Zhe <zhe.he@windriver.com>
---
v2:
- Split printk cleanups into a single patch
- Add pr_fmt for mod name

 arch/x86/kernel/check.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c
index cc8258a..a3d9649 100644
--- a/arch/x86/kernel/check.c
+++ b/arch/x86/kernel/check.c
@@ -1,4 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/kthread.h>
@@ -128,7 +131,8 @@ void __init setup_bios_corruption_check(void)
 	}
 
 	if (num_scan_areas)
-		printk(KERN_INFO "Scanning %d areas for low memory corruption\n", num_scan_areas);
+		pr_info("Scanning %d areas for low memory corruption\n",
+			num_scan_areas);
 }
 
 
@@ -147,7 +151,7 @@ void check_for_bios_corruption(void)
 		for (; size; addr++, size -= sizeof(unsigned long)) {
 			if (!*addr)
 				continue;
-			printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n",
+			pr_err("Corrupted low memory at %p (%lx phys) = %08lx\n",
 			       addr, __pa(addr), *addr);
 			corruption = 1;
 			*addr = 0;
@@ -172,7 +176,7 @@ static int start_periodic_check_for_corruption(void)
 	if (!num_scan_areas || !memory_corruption_check || corruption_check_period == 0)
 		return 0;
 
-	printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n",
+	pr_info("Scanning for low memory corruption every %d seconds\n",
 	       corruption_check_period);
 
 	/* First time we run the checks right away */
-- 
2.7.4

Re: [PATCH v2 1/2] x86: corruption-check: Passing memory_corruption_check to command line causes panic

[He Zhe]

Could you please provide your input? Thanks.

Zhe

On 2018年08月14日 23:33, zhe.he@windriver.com wrote:
> From: He Zhe <zhe.he@windriver.com>
>
> memory_corruption_check[{_period|_size}]'s handlers do not check input
> argument before passing it to kstrtoul or simple_strtoull. The argument
> would be a NULL pointer if each of the kernel parameters, without its
> value, is set in command line and thus cause the following panic.
>
> PANIC: early exception 0xe3 IP 10:ffffffff73587c22 error 0 cr2 0x0
> [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #2
> [    0.000000] RIP: 0010:kstrtoull+0x2/0x10
> ...
> [    0.000000] Call Trace
> [    0.000000]  ? set_corruption_check+0x21/0x49
> [    0.000000]  ? do_early_param+0x4d/0x82
> [    0.000000]  ? parse_args+0x212/0x330
> [    0.000000]  ? rdinit_setup+0x26/0x26
> [    0.000000]  ? parse_early_options+0x20/0x23
> [    0.000000]  ? rdinit_setup+0x26/0x26
> [    0.000000]  ? parse_early_param+0x2d/0x39
> [    0.000000]  ? setup_arch+0x2f7/0xbf4
> [    0.000000]  ? start_kernel+0x5e/0x4c2
> [    0.000000]  ? load_ucode_bsp+0x113/0x12f
> [    0.000000]  ? secondary_startup_64+0xa5/0xb0
>
> This patch adds checks to prevent the panic.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: He Zhe <zhe.he@windriver.com>
> ---
> v2:
> - Split out printk cleanups
> - Add cc to stable@vger.kernel.org
> - Use more meaningful error message
>
>  arch/x86/kernel/check.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c
> index 3339942..cc8258a 100644
> --- a/arch/x86/kernel/check.c
> +++ b/arch/x86/kernel/check.c
> @@ -31,6 +31,11 @@ static __init int set_corruption_check(char *arg)
>  	ssize_t ret;
>  	unsigned long val;
>  
> +	if (!arg) {
> +		pr_err("memory_corruption_check config string not provided\n");
> +		return -EINVAL;
> +	}
> +
>  	ret = kstrtoul(arg, 10, &val);
>  	if (ret)
>  		return ret;
> @@ -45,6 +50,11 @@ static __init int set_corruption_check_period(char *arg)
>  	ssize_t ret;
>  	unsigned long val;
>  
> +	if (!arg) {
> +		pr_err("memory_corruption_check_period config string not provided\n");
> +		return -EINVAL;
> +	}
> +
>  	ret = kstrtoul(arg, 10, &val);
>  	if (ret)
>  		return ret;
> @@ -59,6 +69,11 @@ static __init int set_corruption_check_size(char *arg)
>  	char *end;
>  	unsigned size;
>  
> +	if (!arg) {
> +		pr_err("memory_corruption_check_size config string not provided\n");
> +		return -EINVAL;
> +	}
> +
>  	size = memparse(arg, &end);
>  
>  	if (*end == '\0')

Re: [PATCH v2 1/2] x86: corruption-check: Passing memory_corruption_check to command line causes panic

[Greg KH]

On Mon, Aug 20, 2018 at 04:56:22PM +0800, He Zhe wrote:
> Could you please provide your input? Thanks.

It is the middle of the merge window, we can not do anything with new
patches.  This is a trivial cleanup fix, nothing that is really
important at the moment it will be reviewed in time, please give us a
chance.

thanks,

greg k-h

[tip:x86/boot] x86/corruption-check: Fix panic in memory_corruption_check() when boot option without value is provided

[tip-bot for He Zhe]

Commit-ID:  ccde460b9ae5c2bd5e4742af0a7f623c2daad566
Gitweb:     https://git.kernel.org/tip/ccde460b9ae5c2bd5e4742af0a7f623c2daad566
Author:     He Zhe <zhe.he@windriver.com>
AuthorDate: Tue, 14 Aug 2018 23:33:42 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 10 Sep 2018 14:47:32 +0200

x86/corruption-check: Fix panic in memory_corruption_check() when boot option without value is provided

memory_corruption_check[{_period|_size}]()'s handlers do not check input
argument before passing it to kstrtoul() or simple_strtoull(). The argument
would be a NULL pointer if each of the kernel parameters, without its
value, is set in command line and thus cause the following panic.

PANIC: early exception 0xe3 IP 10:ffffffff73587c22 error 0 cr2 0x0
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #2
[    0.000000] RIP: 0010:kstrtoull+0x2/0x10
...
[    0.000000] Call Trace
[    0.000000]  ? set_corruption_check+0x21/0x49
[    0.000000]  ? do_early_param+0x4d/0x82
[    0.000000]  ? parse_args+0x212/0x330
[    0.000000]  ? rdinit_setup+0x26/0x26
[    0.000000]  ? parse_early_options+0x20/0x23
[    0.000000]  ? rdinit_setup+0x26/0x26
[    0.000000]  ? parse_early_param+0x2d/0x39
[    0.000000]  ? setup_arch+0x2f7/0xbf4
[    0.000000]  ? start_kernel+0x5e/0x4c2
[    0.000000]  ? load_ucode_bsp+0x113/0x12f
[    0.000000]  ? secondary_startup_64+0xa5/0xb0

This patch adds checks to prevent the panic.

Signed-off-by: He Zhe <zhe.he@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: kstewart@linuxfoundation.org
Cc: pombredanne@nexb.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1534260823-87917-1-git-send-email-zhe.he@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/check.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c
index 33399426793e..cc8258a5378b 100644
--- a/arch/x86/kernel/check.c
+++ b/arch/x86/kernel/check.c
@@ -31,6 +31,11 @@ static __init int set_corruption_check(char *arg)
 	ssize_t ret;
 	unsigned long val;
 
+	if (!arg) {
+		pr_err("memory_corruption_check config string not provided\n");
+		return -EINVAL;
+	}
+
 	ret = kstrtoul(arg, 10, &val);
 	if (ret)
 		return ret;
@@ -45,6 +50,11 @@ static __init int set_corruption_check_period(char *arg)
 	ssize_t ret;
 	unsigned long val;
 
+	if (!arg) {
+		pr_err("memory_corruption_check_period config string not provided\n");
+		return -EINVAL;
+	}
+
 	ret = kstrtoul(arg, 10, &val);
 	if (ret)
 		return ret;
@@ -59,6 +69,11 @@ static __init int set_corruption_check_size(char *arg)
 	char *end;
 	unsigned size;
 
+	if (!arg) {
+		pr_err("memory_corruption_check_size config string not provided\n");
+		return -EINVAL;
+	}
+
 	size = memparse(arg, &end);
 
 	if (*end == '\0')

[tip:x86/boot] x86/corruption-check: Use pr_*() instead of printk()

[tip-bot for He Zhe]

Commit-ID:  b1e3a25f5879017fc50ca17f03118b26a19df49a
Gitweb:     https://git.kernel.org/tip/b1e3a25f5879017fc50ca17f03118b26a19df49a
Author:     He Zhe <zhe.he@windriver.com>
AuthorDate: Tue, 14 Aug 2018 23:33:43 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 10 Sep 2018 14:47:33 +0200

x86/corruption-check: Use pr_*() instead of printk()

pr_*() is the preferred style.

Signed-off-by: He Zhe <zhe.he@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: kstewart@linuxfoundation.org
Cc: pombredanne@nexb.com
Link: http://lkml.kernel.org/r/1534260823-87917-2-git-send-email-zhe.he@windriver.com
[ Moved all console output into a single line. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/check.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c
index cc8258a5378b..1979a76bfadd 100644
--- a/arch/x86/kernel/check.c
+++ b/arch/x86/kernel/check.c
@@ -1,4 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/kthread.h>
@@ -41,6 +44,7 @@ static __init int set_corruption_check(char *arg)
 		return ret;
 
 	memory_corruption_check = val;
+
 	return 0;
 }
 early_param("memory_corruption_check", set_corruption_check);
@@ -128,7 +132,7 @@ void __init setup_bios_corruption_check(void)
 	}
 
 	if (num_scan_areas)
-		printk(KERN_INFO "Scanning %d areas for low memory corruption\n", num_scan_areas);
+		pr_info("Scanning %d areas for low memory corruption\n", num_scan_areas);
 }
 
 
@@ -147,8 +151,7 @@ void check_for_bios_corruption(void)
 		for (; size; addr++, size -= sizeof(unsigned long)) {
 			if (!*addr)
 				continue;
-			printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n",
-			       addr, __pa(addr), *addr);
+			pr_err("Corrupted low memory at %p (%lx phys) = %08lx\n", addr, __pa(addr), *addr);
 			corruption = 1;
 			*addr = 0;
 		}
@@ -172,11 +175,11 @@ static int start_periodic_check_for_corruption(void)
 	if (!num_scan_areas || !memory_corruption_check || corruption_check_period == 0)
 		return 0;
 
-	printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n",
-	       corruption_check_period);
+	pr_info("Scanning for low memory corruption every %d seconds\n", corruption_check_period);
 
 	/* First time we run the checks right away */
 	schedule_delayed_work(&bios_check_work, 0);
+
 	return 0;
 }
 device_initcall(start_periodic_check_for_corruption);