* [PATCH 2/3] Add tracing_off_event() calls to BUG() and WARN() paths
2010-03-18 13:48 [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Chase Douglas
@ 2010-03-18 13:48 ` Chase Douglas
2010-03-18 13:48 ` [PATCH 3/3] Stop tracing on a schedule bug Chase Douglas
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Chase Douglas @ 2010-03-18 13:48 UTC (permalink / raw)
To: linux-kernel; +Cc: Steven Rostedt
This change adds tracing_off_event() calls, which stop debug tracing,
when a BUG() or WARN() function is called. The stoppage depends on
commandline paramenter tracing_off={bug,warn,none}. The default is
"bug", so only the BUG() paths will stop tracing.
Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
---
kernel/panic.c | 4 +++-
lib/bug.c | 2 ++
2 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/kernel/panic.c b/kernel/panic.c
index 13d966b..f0ff321 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -319,7 +319,7 @@ int oops_may_print(void)
*/
void oops_enter(void)
{
- tracing_off();
+ tracing_off_event(TRACE_EVENT_BUG);
/* can't trust the integrity of the kernel anymore: */
debug_locks_off();
do_oops_enter_exit();
@@ -369,6 +369,8 @@ static void warn_slowpath_common(const char *file, int line, void *caller, struc
{
const char *board;
+ tracing_off_event(TRACE_EVENT_WARN);
+
printk(KERN_WARNING "------------[ cut here ]------------\n");
printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
board = dmi_get_system_info(DMI_PRODUCT_NAME);
diff --git a/lib/bug.c b/lib/bug.c
index 300e41a..457c1eb 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -154,6 +154,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
warning = (bug->flags & BUGFLAG_WARNING) != 0;
}
+ tracing_off_event(warning ? TRACE_EVENT_WARN : TRACE_EVENT_BUG);
+
if (warning) {
/* this is a WARN_ON rather than BUG/BUG_ON */
if (file)
--
1.6.3.3
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 3/3] Stop tracing on a schedule bug
2010-03-18 13:48 [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Chase Douglas
2010-03-18 13:48 ` [PATCH 2/3] Add tracing_off_event() calls to BUG() and WARN() paths Chase Douglas
@ 2010-03-18 13:48 ` Chase Douglas
2010-03-18 14:56 ` [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Steven Rostedt
2010-03-22 16:14 ` Randy Dunlap
3 siblings, 0 replies; 6+ messages in thread
From: Chase Douglas @ 2010-03-18 13:48 UTC (permalink / raw)
To: linux-kernel; +Cc: Steven Rostedt
This change adds a tracing_off_event() call to stop tracing on schedule
bugs unless tracing_off=none was specified on the commandline.
Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
---
kernel/sched.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 150b698..bfe4f05 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3589,6 +3589,8 @@ static noinline void __schedule_bug(struct task_struct *prev)
{
struct pt_regs *regs = get_irq_regs();
+ tracing_off_event(TRACE_EVENT_BUG);
+
printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
prev->comm, prev->pid, preempt_count());
--
1.6.3.3
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur
2010-03-18 13:48 [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Chase Douglas
2010-03-18 13:48 ` [PATCH 2/3] Add tracing_off_event() calls to BUG() and WARN() paths Chase Douglas
2010-03-18 13:48 ` [PATCH 3/3] Stop tracing on a schedule bug Chase Douglas
@ 2010-03-18 14:56 ` Steven Rostedt
2010-03-18 16:27 ` Chase Douglas
2010-03-22 16:14 ` Randy Dunlap
3 siblings, 1 reply; 6+ messages in thread
From: Steven Rostedt @ 2010-03-18 14:56 UTC (permalink / raw)
To: Chase Douglas
Cc: linux-kernel, Frederic Weisbecker, Ingo Molnar, Thomas Gleixner
[ Expanded the Cc list ]
On Thu, 2010-03-18 at 09:48 -0400, Chase Douglas wrote:
> The tracing_off_event() function calls tracing_off() to stop tracing
> when an event occurs. By default, only BUG-type events stop tracing,
> while WARNING type events do not. This is controlled through the
> tracing_off={none,warn,bug} commandline parameter.
>
> Call this function from bug and warning event handlers to enable a user
> to debug their kernel by starting a trace, hitting an event, and then
> retrieving trace info knowing that the trace was stopped right after the
> event was hit.
>
> Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
> ---
> include/linux/kernel.h | 5 +++++
> kernel/trace/ring_buffer.c | 34 ++++++++++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 7f07074..107091f 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -478,16 +478,21 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
> *
> * Most likely, you want to use tracing_on/tracing_off.
> */
> +#define TRACE_EVENT_BUG 0
> +#define TRACE_EVENT_WARN 1
This should probably be an enum.
> +
> #ifdef CONFIG_RING_BUFFER
> void tracing_on(void);
> void tracing_off(void);
> /* trace_off_permanent stops recording with no way to bring it back */
> void tracing_off_permanent(void);
> +void tracing_off_event(long event);
> int tracing_is_on(void);
> #else
> static inline void tracing_on(void) { }
> static inline void tracing_off(void) { }
> static inline void tracing_off_permanent(void) { }
> +static inline void tracing_off_event(long event) { }
> static inline int tracing_is_on(void) { return 0; }
> #endif
> #ifdef CONFIG_TRACING
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 0287f9f..b148862 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -193,6 +193,40 @@ void tracing_off_permanent(void)
> set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags);
> }
>
> +static long tracing_event_mask = TRACE_EVENT_BUG;
That's a bad name. It does not seem to be a mask but seems to be a
control setting. Maybe call it tracing_event_off_ctrl ?
-- Steve
> +
> +/**
> + * tracing_off_event - turn off tracing depending on event type
> + *
> + * This function checks the event type to determine whether tracing should be
> + * disabled. Useful for disabling tracing on bugs or warnings.
> + */
> +void tracing_off_event(long event)
> +{
> + if (event <= tracing_event_mask)
> + tracing_off();
> +}
> +EXPORT_SYMBOL_GPL(tracing_off_event);
> +
> +static int __init tracing_off_event_setup(char *str)
> +{
> + if (!strcmp("none", str))
> + tracing_event_mask = -1;
> + else if (!strcmp("bug", str))
> + tracing_event_mask = TRACE_EVENT_BUG;
> + else if (!strcmp("warn", str))
> + tracing_event_mask = TRACE_EVENT_WARN;
> + else
> + {
> + printk(KERN_NOTICE "Invalid value passed for tracing_off parameter\n");
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +__setup("tracing_off=", tracing_off_event_setup);
> +
> /**
> * tracing_is_on - show state of ring buffers enabled
> */
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur
2010-03-18 14:56 ` [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Steven Rostedt
@ 2010-03-18 16:27 ` Chase Douglas
0 siblings, 0 replies; 6+ messages in thread
From: Chase Douglas @ 2010-03-18 16:27 UTC (permalink / raw)
To: rostedt; +Cc: linux-kernel, Frederic Weisbecker, Ingo Molnar, Thomas Gleixner
On Thu, Mar 18, 2010 at 10:56 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
> [ Expanded the Cc list ]
>
> On Thu, 2010-03-18 at 09:48 -0400, Chase Douglas wrote:
>> The tracing_off_event() function calls tracing_off() to stop tracing
>> when an event occurs. By default, only BUG-type events stop tracing,
>> while WARNING type events do not. This is controlled through the
>> tracing_off={none,warn,bug} commandline parameter.
>>
>> Call this function from bug and warning event handlers to enable a user
>> to debug their kernel by starting a trace, hitting an event, and then
>> retrieving trace info knowing that the trace was stopped right after the
>> event was hit.
>>
>> Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
>> ---
>> include/linux/kernel.h | 5 +++++
>> kernel/trace/ring_buffer.c | 34 ++++++++++++++++++++++++++++++++++
>> 2 files changed, 39 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
>> index 7f07074..107091f 100644
>> --- a/include/linux/kernel.h
>> +++ b/include/linux/kernel.h
>> @@ -478,16 +478,21 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
>> *
>> * Most likely, you want to use tracing_on/tracing_off.
>> */
>> +#define TRACE_EVENT_BUG 0
>> +#define TRACE_EVENT_WARN 1
>
> This should probably be an enum.
>
>> +
>> #ifdef CONFIG_RING_BUFFER
>> void tracing_on(void);
>> void tracing_off(void);
>> /* trace_off_permanent stops recording with no way to bring it back */
>> void tracing_off_permanent(void);
>> +void tracing_off_event(long event);
>> int tracing_is_on(void);
>> #else
>> static inline void tracing_on(void) { }
>> static inline void tracing_off(void) { }
>> static inline void tracing_off_permanent(void) { }
>> +static inline void tracing_off_event(long event) { }
>> static inline int tracing_is_on(void) { return 0; }
>> #endif
>> #ifdef CONFIG_TRACING
>> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
>> index 0287f9f..b148862 100644
>> --- a/kernel/trace/ring_buffer.c
>> +++ b/kernel/trace/ring_buffer.c
>> @@ -193,6 +193,40 @@ void tracing_off_permanent(void)
>> set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags);
>> }
>>
>> +static long tracing_event_mask = TRACE_EVENT_BUG;
>
> That's a bad name. It does not seem to be a mask but seems to be a
> control setting. Maybe call it tracing_event_off_ctrl ?
I'll fix these two things up and resend.
Thanks,
Chase
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur
2010-03-18 13:48 [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Chase Douglas
` (2 preceding siblings ...)
2010-03-18 14:56 ` [PATCH 1/3] Add tracing_off_event() to stop tracing when a bug or warning occur Steven Rostedt
@ 2010-03-22 16:14 ` Randy Dunlap
3 siblings, 0 replies; 6+ messages in thread
From: Randy Dunlap @ 2010-03-22 16:14 UTC (permalink / raw)
To: Chase Douglas; +Cc: linux-kernel, Steven Rostedt
On Thu, 18 Mar 2010 09:48:50 -0400 Chase Douglas wrote:
> The tracing_off_event() function calls tracing_off() to stop tracing
> when an event occurs. By default, only BUG-type events stop tracing,
> while WARNING type events do not. This is controlled through the
> tracing_off={none,warn,bug} commandline parameter.
>
> Call this function from bug and warning event handlers to enable a user
> to debug their kernel by starting a trace, hitting an event, and then
> retrieving trace info knowing that the trace was stopped right after the
> event was hit.
>
> Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
> ---
> include/linux/kernel.h | 5 +++++
> kernel/trace/ring_buffer.c | 34 ++++++++++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 7f07074..107091f 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -478,16 +478,21 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
> *
> * Most likely, you want to use tracing_on/tracing_off.
> */
> +#define TRACE_EVENT_BUG 0
> +#define TRACE_EVENT_WARN 1
> +
> #ifdef CONFIG_RING_BUFFER
> void tracing_on(void);
> void tracing_off(void);
> /* trace_off_permanent stops recording with no way to bring it back */
> void tracing_off_permanent(void);
> +void tracing_off_event(long event);
> int tracing_is_on(void);
> #else
> static inline void tracing_on(void) { }
> static inline void tracing_off(void) { }
> static inline void tracing_off_permanent(void) { }
> +static inline void tracing_off_event(long event) { }
> static inline int tracing_is_on(void) { return 0; }
> #endif
> #ifdef CONFIG_TRACING
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 0287f9f..b148862 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -193,6 +193,40 @@ void tracing_off_permanent(void)
> set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags);
> }
>
> +static long tracing_event_mask = TRACE_EVENT_BUG;
> +
> +/**
> + * tracing_off_event - turn off tracing depending on event type
Please add the function parameter to the kernel-doc to make it complete
& prevent warnings; something like:
* @event: which event happened
> + *
> + * This function checks the event type to determine whether tracing should be
> + * disabled. Useful for disabling tracing on bugs or warnings.
> + */
> +void tracing_off_event(long event)
> +{
> + if (event <= tracing_event_mask)
> + tracing_off();
> +}
> +EXPORT_SYMBOL_GPL(tracing_off_event);
> +
> +static int __init tracing_off_event_setup(char *str)
> +{
> + if (!strcmp("none", str))
> + tracing_event_mask = -1;
> + else if (!strcmp("bug", str))
> + tracing_event_mask = TRACE_EVENT_BUG;
> + else if (!strcmp("warn", str))
> + tracing_event_mask = TRACE_EVENT_WARN;
> + else
> + {
> + printk(KERN_NOTICE "Invalid value passed for tracing_off parameter\n");
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +__setup("tracing_off=", tracing_off_event_setup);
> +
> /**
> * tracing_is_on - show state of ring buffers enabled
> */
> --
---
~Randy
^ permalink raw reply [flat|nested] 6+ messages in thread