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.
Signed-off-by: He Zhe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
v2:
Split out the addition of pr_fmt and the unsigned update
v3:
Remove error message for NULL pointer
Add check and error message for over 4G use
v4:
Split each piece into one patch
kernel/printk/printk.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9bf5404..06045ab 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1048,7 +1048,12 @@ 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)
+ return -EINVAL;
+
+ size = memparse(str, &str);
log_buf_len_update(size);
--
2.7.4
From: He Zhe <[email protected]>
Give explicit error for users who want to use larger log buffer.
Signed-off-by: He Zhe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
kernel/printk/printk.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index b84aac0..5ccfd5d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1039,18 +1039,23 @@ void log_buf_vmcoreinfo_setup(void)
static unsigned long __initdata new_log_buf_len;
/* we practice scaling the ring buffer by powers of 2 */
-static void __init log_buf_len_update(unsigned size)
+static void __init log_buf_len_update(u64 size)
{
+ if (size > UINT_MAX) {
+ size = UINT_MAX;
+ pr_err("log_buf over 4G is not supported.\n");
+ }
+
if (size)
size = roundup_pow_of_two(size);
if (size > log_buf_len)
- new_log_buf_len = size;
+ new_log_buf_len = (unsigned long)size;
}
/* save requested log_buf_len since it's too early to process it */
static int __init log_buf_len_setup(char *str)
{
- unsigned int size;
+ u64 size;
if (!str)
return -EINVAL;
--
2.7.4
From: He Zhe <[email protected]>
Add KBUILD_MODNAME to make prints more clear.
Signed-off-by: He Zhe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
kernel/printk/printk.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c9a0be3..b84aac0 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>
--
2.7.4
From: He Zhe <[email protected]>
Correct wrong casting that might cut off the normal output.
Signed-off-by: He Zhe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
kernel/printk/printk.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 06045ab..c9a0be3 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2356,8 +2356,9 @@ void console_unlock(void)
printk_safe_enter_irqsave(flags);
raw_spin_lock(&logbuf_lock);
if (console_seq < log_first_seq) {
- len = sprintf(text, "** %u printk messages dropped **\n",
- (unsigned)(log_first_seq - console_seq));
+ len = sprintf(text,
+ "** %llu printk messages dropped **\n",
+ log_first_seq - console_seq);
/* messages are gone, move to first one */
console_seq = log_first_seq;
--
2.7.4
On (09/29/18 22:48), [email protected] wrote:
>
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
Plus this one
---
kernel/printk/printk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c9068074dd09..e32f93a2fa84 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2732,7 +2732,7 @@ void register_console(struct console *newcon)
if (newcon->flags & CON_EXTENDED)
if (!nr_ext_console_drivers++)
- pr_info("printk: continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n");
+ pr_info("continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n");
if (newcon->flags & CON_PRINTBUFFER) {
/*
---
-ss