2010-06-26 19:14:01

by Anton Blanchard

[permalink] [raw]
Subject: [PATCH 1/2] Make lib/bug.c WARN implementation match the kernel/panic.c one


There are a few issues with the exception based WARN implementation in
lib/bug.c:

- Inconsistent printk flags. The "cut here" line is printed at KERN_EMERG, so
the console and all logged in users see the single line:

------------[ cut here ]------------

for each WARN. Fix this so we print everything at KERN_WARNING to match the
kernel/panic.c version.

- The lib/bug.c WARN would print "Badness at". Change it to match the
kernel/panic.c version which prints "WARNING: at".

- Print the list of modules, similar to kernel/panic.c of modules, similar to
kernel/panic.c

Signed-off-by: Anton Blanchard <[email protected]>
---

Index: linux-2.6/lib/bug.c
===================================================================
--- linux-2.6.orig/lib/bug.c 2010-06-26 06:09:59.000000000 +1000
+++ linux-2.6/lib/bug.c 2010-06-26 06:24:28.000000000 +1000
@@ -136,8 +136,6 @@ enum bug_trap_type report_bug(unsigned l

bug = find_bug(bugaddr);

- printk(KERN_EMERG "------------[ cut here ]------------\n");
-
file = NULL;
line = 0;
warning = 0;
@@ -156,19 +154,24 @@ enum bug_trap_type report_bug(unsigned l

if (warning) {
/* this is a WARN_ON rather than BUG/BUG_ON */
+ printk(KERN_WARNING "------------[ cut here ]------------\n");
+
if (file)
- printk(KERN_ERR "Badness at %s:%u\n",
+ printk(KERN_WARNING "WARNING: at %s:%u\n",
file, line);
else
- printk(KERN_ERR "Badness at %p "
+ printk(KERN_WARNING "WARNING: at %p "
"[verbose debug info unavailable]\n",
(void *)bugaddr);

+ print_modules();
show_regs(regs);
add_taint(BUG_GET_TAINT(bug));
return BUG_TRAP_TYPE_WARN;
}

+ printk(KERN_EMERG "------------[ cut here ]------------\n");
+
if (file)
printk(KERN_CRIT "kernel BUG at %s:%u!\n",
file, line);


2010-06-26 19:14:04

by Anton Blanchard

[permalink] [raw]
Subject: [PATCH 2/2] Add oops end marker to lib/bug.c WARN implementation


We are missing the oops end marker for the exception based WARN implementation
in lib/bug.c. This is useful for logfile analysis tools.

Signed-off-by: Anton Blanchard <[email protected]>
---

Index: linux-2.6/include/linux/kernel.h
===================================================================
--- linux-2.6.orig/include/linux/kernel.h 2010-06-26 06:29:35.000000000 +1000
+++ linux-2.6/include/linux/kernel.h 2010-06-26 06:30:27.000000000 +1000
@@ -177,6 +177,7 @@ NORET_TYPE void panic(const char * fmt,
__attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
extern void oops_enter(void);
extern void oops_exit(void);
+void print_oops_end_marker(void);
extern int oops_may_print(void);
NORET_TYPE void do_exit(long error_code)
ATTRIB_NORET;
Index: linux-2.6/kernel/panic.c
===================================================================
--- linux-2.6.orig/kernel/panic.c 2010-06-26 06:29:35.000000000 +1000
+++ linux-2.6/kernel/panic.c 2010-06-26 06:30:05.000000000 +1000
@@ -344,7 +344,7 @@ static int init_oops_id(void)
}
late_initcall(init_oops_id);

-static void print_oops_end_marker(void)
+void print_oops_end_marker(void)
{
init_oops_id();
printk(KERN_WARNING "---[ end trace %016llx ]---\n",
Index: linux-2.6/lib/bug.c
===================================================================
--- linux-2.6.orig/lib/bug.c 2010-06-26 06:29:35.000000000 +1000
+++ linux-2.6/lib/bug.c 2010-06-26 06:31:28.000000000 +1000
@@ -166,6 +166,7 @@ enum bug_trap_type report_bug(unsigned l

print_modules();
show_regs(regs);
+ print_oops_end_marker();
add_taint(BUG_GET_TAINT(bug));
return BUG_TRAP_TYPE_WARN;
}

2010-06-26 20:04:33

by Kirill A. Shutemov

[permalink] [raw]
Subject: Re: [PATCH 1/2] Make lib/bug.c WARN implementation match the kernel/panic.c one

On Sun, Jun 27, 2010 at 05:10:59AM +1000, Anton Blanchard wrote:
>
> There are a few issues with the exception based WARN implementation in
> lib/bug.c:
>
> - Inconsistent printk flags. The "cut here" line is printed at KERN_EMERG, so
> the console and all logged in users see the single line:
>
> ------------[ cut here ]------------
>
> for each WARN. Fix this so we print everything at KERN_WARNING to match the
> kernel/panic.c version.
>
> - The lib/bug.c WARN would print "Badness at". Change it to match the
> kernel/panic.c version which prints "WARNING: at".
>
> - Print the list of modules, similar to kernel/panic.c of modules, similar to
> kernel/panic.c
>
> Signed-off-by: Anton Blanchard <[email protected]>
> ---
>
> Index: linux-2.6/lib/bug.c
> ===================================================================
> --- linux-2.6.orig/lib/bug.c 2010-06-26 06:09:59.000000000 +1000
> +++ linux-2.6/lib/bug.c 2010-06-26 06:24:28.000000000 +1000
> @@ -136,8 +136,6 @@ enum bug_trap_type report_bug(unsigned l
>
> bug = find_bug(bugaddr);
>
> - printk(KERN_EMERG "------------[ cut here ]------------\n");
> -
> file = NULL;
> line = 0;
> warning = 0;
> @@ -156,19 +154,24 @@ enum bug_trap_type report_bug(unsigned l
>
> if (warning) {
> /* this is a WARN_ON rather than BUG/BUG_ON */
> + printk(KERN_WARNING "------------[ cut here ]------------\n");
> +
> if (file)
> - printk(KERN_ERR "Badness at %s:%u\n",
> + printk(KERN_WARNING "WARNING: at %s:%u\n",
> file, line);
> else
> - printk(KERN_ERR "Badness at %p "
> + printk(KERN_WARNING "WARNING: at %p "
> "[verbose debug info unavailable]\n",
> (void *)bugaddr);
>
> + print_modules();
> show_regs(regs);
> add_taint(BUG_GET_TAINT(bug));
> return BUG_TRAP_TYPE_WARN;
> }
>
> + printk(KERN_EMERG "------------[ cut here ]------------\n");
> +

Hm... Why do you use KERN_EMERG here?

> if (file)
> printk(KERN_CRIT "kernel BUG at %s:%u!\n",
> file, line);
> --
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--
Kirill A. Shutemov