From: He Zhe <[email protected]>
log_buf_len_setup does not check input argument before passing it to
simple_strtoull. The argument would be a NULL pointer if "log_buf_len",
without its value, is set in command line and thus causes the following
panic.
PANIC: early exception 0xe3 IP 10:ffffffffaaeacd0d error 0 cr2 0x0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1
[ 0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70
...
[ 0.000000] Call Trace:
[ 0.000000] simple_strtoull+0x29/0x70
[ 0.000000] memparse+0x26/0x90
[ 0.000000] log_buf_len_setup+0x17/0x22
[ 0.000000] do_early_param+0x57/0x8e
[ 0.000000] parse_args+0x208/0x320
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_options+0x29/0x2d
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_param+0x36/0x4d
[ 0.000000] setup_arch+0x336/0x99e
[ 0.000000] start_kernel+0x6f/0x4ee
[ 0.000000] x86_64_start_reservations+0x24/0x26
[ 0.000000] x86_64_start_kernel+0x6f/0x72
[ 0.000000] secondary_startup_64+0xa4/0xb0
This patch adds a check to prevent the panic, adds KBUILD_MODNAME to
prints and correct bare use of 'unsigned'.
Signed-off-by: He Zhe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
kernel/printk/printk.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9bf5404..f6d4030 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -16,6 +16,8 @@
* 01Mar01 Andrew Morton
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/tty.h>
@@ -1048,7 +1050,14 @@ static void __init log_buf_len_update(unsigned size)
/* save requested log_buf_len since it's too early to process it */
static int __init log_buf_len_setup(char *str)
{
- unsigned size = memparse(str, &str);
+ unsigned int size;
+
+ if (!str) {
+ pr_err("Config string not provided\n");
+ return -EINVAL;
+ }
+
+ size = memparse(str, &str);
log_buf_len_update(size);
--
2.7.4
On Tue, 18 Sep 2018 23:42:34 +0800
<[email protected]> wrote:
> From: He Zhe <[email protected]>
>
> log_buf_len_setup does not check input argument before passing it to
> simple_strtoull. The argument would be a NULL pointer if "log_buf_len",
> without its value, is set in command line and thus causes the following
> panic.
>
> PANIC: early exception 0xe3 IP 10:ffffffffaaeacd0d error 0 cr2 0x0
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1
> [ 0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70
> ...
> [ 0.000000] Call Trace:
> [ 0.000000] simple_strtoull+0x29/0x70
> [ 0.000000] memparse+0x26/0x90
> [ 0.000000] log_buf_len_setup+0x17/0x22
> [ 0.000000] do_early_param+0x57/0x8e
> [ 0.000000] parse_args+0x208/0x320
> [ 0.000000] ? rdinit_setup+0x30/0x30
> [ 0.000000] parse_early_options+0x29/0x2d
> [ 0.000000] ? rdinit_setup+0x30/0x30
> [ 0.000000] parse_early_param+0x36/0x4d
> [ 0.000000] setup_arch+0x336/0x99e
> [ 0.000000] start_kernel+0x6f/0x4ee
> [ 0.000000] x86_64_start_reservations+0x24/0x26
> [ 0.000000] x86_64_start_kernel+0x6f/0x72
> [ 0.000000] secondary_startup_64+0xa4/0xb0
>
> This patch adds a check to prevent the panic, adds KBUILD_MODNAME to
> prints and correct bare use of 'unsigned'.
Hi!
The addition of pr_fmt and the unsigned update should be a separate
patch. This is a bug fix and only the bug fix should be included, as it
is going to be backported.
Thanks!
-- Steve
>
> Signed-off-by: He Zhe <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---
> kernel/printk/printk.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 9bf5404..f6d4030 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -16,6 +16,8 @@
> * 01Mar01 Andrew Morton
> */
>
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> #include <linux/kernel.h>
> #include <linux/mm.h>
> #include <linux/tty.h>
> @@ -1048,7 +1050,14 @@ static void __init log_buf_len_update(unsigned size)
> /* save requested log_buf_len since it's too early to process it */
> static int __init log_buf_len_setup(char *str)
> {
> - unsigned size = memparse(str, &str);
> + unsigned int size;
> +
> + if (!str) {
> + pr_err("Config string not provided\n");
> + return -EINVAL;
> + }
> +
> + size = memparse(str, &str);
>
> log_buf_len_update(size);
>