* BUG and WARN kernel log levels
@ 2016-08-15 18:53 Kees Cook
2016-08-15 19:00 ` Joe Perches
0 siblings, 1 reply; 7+ messages in thread
From: Kees Cook @ 2016-08-15 18:53 UTC (permalink / raw)
To: Joe Perches; +Cc: LKML
Hi,
So, I noticed that asm-gemeric/bug.h defines BUG() without a log level:
#ifndef HAVE_ARCH_BUG
#define BUG() do { \
printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
Seems like it should have one?
Also, I think we might want to examine WARN() a bit... it doesn't have
a log level either, but only a fraction of callers set one:
$ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep -v KERN_ | wc -l
2735
$ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep KERN_ | wc -l
77
If I'm reading checkpatch.pl correctly, it doesn't warn about missing
log levels on WARN calls, but I think it should.
How do you think is best to clean this up?
Mainly, I'd like to add a format string to BUG, or introduce a new
BUGish call that takes a format...
-Kees
--
Kees Cook
Nexus Security
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: BUG and WARN kernel log levels
2016-08-15 18:53 BUG and WARN kernel log levels Kees Cook
@ 2016-08-15 19:00 ` Joe Perches
2016-08-15 20:28 ` Kees Cook
2016-08-17 16:36 ` Joe Perches
0 siblings, 2 replies; 7+ messages in thread
From: Joe Perches @ 2016-08-15 19:00 UTC (permalink / raw)
To: Kees Cook; +Cc: LKML
On Mon, 2016-08-15 at 11:53 -0700, Kees Cook wrote:
> Hi,
>
> So, I noticed that asm-gemeric/bug.h defines BUG() without a log level:
>
> #ifndef HAVE_ARCH_BUG
> #define BUG() do { \
> printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
>
> Seems like it should have one?
>
> Also, I think we might want to examine WARN() a bit... it doesn't have
> a log level either, but only a fraction of callers set one:
>
> $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep -v KERN_ | wc -l
> 2735
>
> $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep KERN_ | wc -l
> 77
>
> If I'm reading checkpatch.pl correctly, it doesn't warn about missing
> log levels on WARN calls, but I think it should.
>
> How do you think is best to clean this up?
>
> Mainly, I'd like to add a format string to BUG, or introduce a new
> BUGish call that takes a format...
I once suggested something similar awhile ago.
https://lkml.org/lkml/2008/7/8/261
I think it's best to remove any KERN_<LEVEL> from the use of
all the WARN variants and add it to the WARN definitions.
Same with BUG.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: BUG and WARN kernel log levels
2016-08-15 19:00 ` Joe Perches
@ 2016-08-15 20:28 ` Kees Cook
2016-08-15 20:39 ` Joe Perches
2016-08-17 16:36 ` Joe Perches
1 sibling, 1 reply; 7+ messages in thread
From: Kees Cook @ 2016-08-15 20:28 UTC (permalink / raw)
To: Joe Perches; +Cc: LKML
On Mon, Aug 15, 2016 at 12:00 PM, Joe Perches <joe@perches.com> wrote:
> On Mon, 2016-08-15 at 11:53 -0700, Kees Cook wrote:
>> Hi,
>>
>> So, I noticed that asm-gemeric/bug.h defines BUG() without a log level:
>>
>> #ifndef HAVE_ARCH_BUG
>> #define BUG() do { \
>> printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
>>
>> Seems like it should have one?
>>
>> Also, I think we might want to examine WARN() a bit... it doesn't have
>> a log level either, but only a fraction of callers set one:
>>
>> $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep -v KERN_ | wc -l
>> 2735
>>
>> $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep KERN_ | wc -l
>> 77
>>
>> If I'm reading checkpatch.pl correctly, it doesn't warn about missing
>> log levels on WARN calls, but I think it should.
>>
>> How do you think is best to clean this up?
>>
>> Mainly, I'd like to add a format string to BUG, or introduce a new
>> BUGish call that takes a format...
>
> I once suggested something similar awhile ago.
> https://lkml.org/lkml/2008/7/8/261
>
> I think it's best to remove any KERN_<LEVEL> from the use of
> all the WARN variants and add it to the WARN definitions.
Yeah, that's what I was thinking too. It does mean that the format
needs to be a const char string, though. I haven't checked all of them
but most seem to be. It's an easy fix to move them to "%s" as needed,
though.
> Same with BUG.
Yeah, though for full effect, it needs to be plumbed into each
architecture's BUG handler. Mainly what I don't like is that if I do
this on x86:
pr_err("eek, terrible thing\n");
BUG();
I get a dmesg that read:
eek, terrible thing
=== cut here ===
...traceback, etc
I'd like the "eek" part to be inside the "cut here". And I'd like BUGs
to be able to be more verbose.
-Kees
--
Kees Cook
Nexus Security
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: BUG and WARN kernel log levels
2016-08-15 20:28 ` Kees Cook
@ 2016-08-15 20:39 ` Joe Perches
0 siblings, 0 replies; 7+ messages in thread
From: Joe Perches @ 2016-08-15 20:39 UTC (permalink / raw)
To: Kees Cook; +Cc: LKML
On Mon, 2016-08-15 at 13:28 -0700, Kees Cook wrote:
> On Mon, Aug 15, 2016 at 12:00 PM, Joe Perches <joe@perches.com> wrote:
> > On Mon, 2016-08-15 at 11:53 -0700, Kees Cook wrote:
> > > So, I noticed that asm-gemeric/bug.h defines BUG() without a log level:
> > >
> > > #ifndef HAVE_ARCH_BUG
> > > #define BUG() do { \
> > > printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
> > >
> > > Seems like it should have one?
> > >
> > > Also, I think we might want to examine WARN() a bit... it doesn't have
> > > a log level either, but only a fraction of callers set one:
> > >
> > > $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep -v KERN_ | wc -l
> > > 2735
> > >
> > > $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep KERN_ | wc -l
> > > 77
> > >
> > > If I'm reading checkpatch.pl correctly, it doesn't warn about missing
> > > log levels on WARN calls, but I think it should.
> > >
> > > How do you think is best to clean this up?
> > >
> > > Mainly, I'd like to add a format string to BUG, or introduce a new
> > > BUGish call that takes a format...
> > I once suggested something similar awhile ago.
> > https://lkml.org/lkml/2008/7/8/261
> >
> > I think it's best to remove any KERN_ from the use of
> > all the WARN variants and add it to the WARN definitions.
> Yeah, that's what I was thinking too. It does mean that the format
> needs to be a const char string, though.
No it doesn't mean that.
Prefixing KERN_WARNING to the const char[] types and using
KERN_WARNING "%pV" could work for the non const char[] types
Or maybe use the same KERN_WARNING "%pV" for simpler code.
> > Same with BUG.
> Yeah, though for full effect, it needs to be plumbed into each
> architecture's BUG handler. Mainly what I don't like is that if I do
> this on x86:
>
> pr_err("eek, terrible thing\n");
> BUG();
>
> I get a dmesg that read:
>
> eek, terrible thing
> === cut here ===
> ...traceback, etc
>
> I'd like the "eek" part to be inside the "cut here". And I'd like BUGs
> to be able to be more verbose.
Maybe add BUG_MSG/BUG_ON_MSG or some such.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: BUG and WARN kernel log levels
2016-08-15 19:00 ` Joe Perches
2016-08-15 20:28 ` Kees Cook
@ 2016-08-17 16:36 ` Joe Perches
2016-08-17 21:19 ` Kees Cook
1 sibling, 1 reply; 7+ messages in thread
From: Joe Perches @ 2016-08-17 16:36 UTC (permalink / raw)
To: Kees Cook; +Cc: LKML
On Mon, 2016-08-15 at 12:00 -0700, Joe Perches wrote:
> On Mon, 2016-08-15 at 11:53 -0700, Kees Cook wrote:
> >
> > Hi,
> >
> > So, I noticed that asm-gemeric/bug.h defines BUG() without a log level:
> >
> > #ifndef HAVE_ARCH_BUG
> > #define BUG() do { \
> > printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
> >
> > Seems like it should have one?
> >
> > Also, I think we might want to examine WARN() a bit... it doesn't have
> > a log level either, but only a fraction of callers set one:
> >
> > $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep -v KERN_ | wc -l
> > 2735
> >
> > $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep KERN_ | wc -l
> > 77
> >
> > If I'm reading checkpatch.pl correctly, it doesn't warn about missing
> > log levels on WARN calls, but I think it should.
> >
> > How do you think is best to clean this up?
> >
> > Mainly, I'd like to add a format string to BUG, or introduce a new
> > BUGish call that takes a format...
> I once suggested something similar awhile ago.
> https://lkml.org/lkml/2008/7/8/261
And here I submitted patches:
https://lkml.org/lkml/2010/10/30/176
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: BUG and WARN kernel log levels
2016-08-17 16:36 ` Joe Perches
@ 2016-08-17 21:19 ` Kees Cook
2016-08-17 22:49 ` Joe Perches
0 siblings, 1 reply; 7+ messages in thread
From: Kees Cook @ 2016-08-17 21:19 UTC (permalink / raw)
To: Joe Perches; +Cc: LKML
On Wed, Aug 17, 2016 at 9:36 AM, Joe Perches <joe@perches.com> wrote:
> On Mon, 2016-08-15 at 12:00 -0700, Joe Perches wrote:
>> On Mon, 2016-08-15 at 11:53 -0700, Kees Cook wrote:
>> >
>> > Hi,
>> >
>> > So, I noticed that asm-gemeric/bug.h defines BUG() without a log level:
>> >
>> > #ifndef HAVE_ARCH_BUG
>> > #define BUG() do { \
>> > printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
>> >
>> > Seems like it should have one?
>> >
>> > Also, I think we might want to examine WARN() a bit... it doesn't have
>> > a log level either, but only a fraction of callers set one:
>> >
>> > $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep -v KERN_ | wc -l
>> > 2735
>> >
>> > $ git grep -E 'WARN(_TAINT|)(_RATELIMIT|_ONCE|)\([^\)]' | grep KERN_ | wc -l
>> > 77
>> >
>> > If I'm reading checkpatch.pl correctly, it doesn't warn about missing
>> > log levels on WARN calls, but I think it should.
>> >
>> > How do you think is best to clean this up?
>> >
>> > Mainly, I'd like to add a format string to BUG, or introduce a new
>> > BUGish call that takes a format...
>> I once suggested something similar awhile ago.
>> https://lkml.org/lkml/2008/7/8/261
>
> And here I submitted patches:
> https://lkml.org/lkml/2010/10/30/176
Ah, I see some of this series landed. I see commits scattered in the
tree, but not as many as you sent, I think. What still remains?
-Kees
--
Kees Cook
Nexus Security
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: BUG and WARN kernel log levels
2016-08-17 21:19 ` Kees Cook
@ 2016-08-17 22:49 ` Joe Perches
0 siblings, 0 replies; 7+ messages in thread
From: Joe Perches @ 2016-08-17 22:49 UTC (permalink / raw)
To: Kees Cook; +Cc: LKML
On Wed, 2016-08-17 at 14:19 -0700, Kees Cook wrote:
> On Wed, Aug 17, 2016 at 9:36 AM, Joe Perches <joe@perches.com> wrote:
[]
> > And here I submitted patches:
> > https://lkml.org/lkml/2010/10/30/176
> Ah, I see some of this series landed. I see commits scattered in the
> tree, but not as many as you sent, I think. What still remains?
No idea.
There wasn't any enthusiasm to apply the asm-generic
patch so I didn't push it.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-08-17 22:49 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-15 18:53 BUG and WARN kernel log levels Kees Cook
2016-08-15 19:00 ` Joe Perches
2016-08-15 20:28 ` Kees Cook
2016-08-15 20:39 ` Joe Perches
2016-08-17 16:36 ` Joe Perches
2016-08-17 21:19 ` Kees Cook
2016-08-17 22:49 ` Joe Perches
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