* [PATCH] stacktrace: don't skip first entry on noncurrent tasks
@ 2019-10-25 6:52 Jiri Slaby
2019-10-25 14:21 ` Josh Poimboeuf
0 siblings, 1 reply; 7+ messages in thread
From: Jiri Slaby @ 2019-10-25 6:52 UTC (permalink / raw)
To: tglx; +Cc: linux-kernel, Jiri Slaby, Josh Poimboeuf
When doing cat /proc/<PID>/stack, the output is missing the first entry.
When the current code walks the stack starting in stack_trace_save_tsk,
it skips all scheduler functions (that's OK) plus one more function. But
this one function should be skipped only for the 'current' task as it is
stack_trace_save_tsk proper.
The original code (before the common infrastructure) skipped one
function only for the 'current' task -- see save_stack_trace_tsk before
3599fe12a125. So do so also in the new infrastructure now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
---
kernel/stacktrace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 6d1f68b7e528..d06a2e4d0142 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
struct stacktrace_cookie c = {
.store = store,
.size = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == tsk),
};
if (!try_get_task_stack(tsk))
--
2.23.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] stacktrace: don't skip first entry on noncurrent tasks
2019-10-25 6:52 [PATCH] stacktrace: don't skip first entry on noncurrent tasks Jiri Slaby
@ 2019-10-25 14:21 ` Josh Poimboeuf
2019-10-29 7:19 ` [PATCH v2] " Jiri Slaby
0 siblings, 1 reply; 7+ messages in thread
From: Josh Poimboeuf @ 2019-10-25 14:21 UTC (permalink / raw)
To: Jiri Slaby; +Cc: tglx, linux-kernel
On Fri, Oct 25, 2019 at 08:52:26AM +0200, Jiri Slaby wrote:
> When doing cat /proc/<PID>/stack, the output is missing the first entry.
> When the current code walks the stack starting in stack_trace_save_tsk,
> it skips all scheduler functions (that's OK) plus one more function. But
> this one function should be skipped only for the 'current' task as it is
> stack_trace_save_tsk proper.
>
> The original code (before the common infrastructure) skipped one
> function only for the 'current' task -- see save_stack_trace_tsk before
> 3599fe12a125. So do so also in the new infrastructure now.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> ---
> kernel/stacktrace.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
> index 6d1f68b7e528..d06a2e4d0142 100644
> --- a/kernel/stacktrace.c
> +++ b/kernel/stacktrace.c
> @@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
> struct stacktrace_cookie c = {
> .store = store,
> .size = size,
> - .skip = skipnr + 1,
> + /* skip this function if they are tracing us */
> + .skip = skipnr + !!(current == tsk),
> };
>
> if (!try_get_task_stack(tsk))
I think a similar change is needed for the other !CONFIG_ARCH_STACKWALK
version of stack_trace_save_tsk() in that file?
--
Josh
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2] stacktrace: don't skip first entry on noncurrent tasks
2019-10-25 14:21 ` Josh Poimboeuf
@ 2019-10-29 7:19 ` Jiri Slaby
2019-10-29 13:35 ` Josh Poimboeuf
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Jiri Slaby @ 2019-10-29 7:19 UTC (permalink / raw)
To: tglx; +Cc: linux-kernel, Jiri Slaby, Josh Poimboeuf
When doing cat /proc/<PID>/stack, the output is missing the first entry.
When the current code walks the stack starting in stack_trace_save_tsk,
it skips all scheduler functions (that's OK) plus one more function. But
this one function should be skipped only for the 'current' task as it is
stack_trace_save_tsk proper.
The original code (before the common infrastructure) skipped one
function only for the 'current' task -- see save_stack_trace_tsk before
3599fe12a125. So do so also in the new infrastructure now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
---
Notes:
[v2] add the same for the !CONFIG_ARCH_STACKWALK case
kernel/stacktrace.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 6d1f68b7e528..48703b252434 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
struct stacktrace_cookie c = {
.store = store,
.size = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == tsk),
};
if (!try_get_task_stack(tsk))
@@ -298,7 +299,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
struct stack_trace trace = {
.entries = store,
.max_entries = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == tsk),
};
save_stack_trace_tsk(task, &trace);
--
2.23.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2] stacktrace: don't skip first entry on noncurrent tasks
2019-10-29 7:19 ` [PATCH v2] " Jiri Slaby
@ 2019-10-29 13:35 ` Josh Poimboeuf
2019-10-30 6:09 ` Jiri Slaby
2019-10-30 7:25 ` [PATCH v3] " Jiri Slaby
2 siblings, 0 replies; 7+ messages in thread
From: Josh Poimboeuf @ 2019-10-29 13:35 UTC (permalink / raw)
To: Jiri Slaby; +Cc: tglx, linux-kernel
On Tue, Oct 29, 2019 at 08:19:44AM +0100, Jiri Slaby wrote:
> When doing cat /proc/<PID>/stack, the output is missing the first entry.
> When the current code walks the stack starting in stack_trace_save_tsk,
> it skips all scheduler functions (that's OK) plus one more function. But
> this one function should be skipped only for the 'current' task as it is
> stack_trace_save_tsk proper.
>
> The original code (before the common infrastructure) skipped one
> function only for the 'current' task -- see save_stack_trace_tsk before
> 3599fe12a125. So do so also in the new infrastructure now.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> ---
>
> Notes:
> [v2] add the same for the !CONFIG_ARCH_STACKWALK case
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] stacktrace: don't skip first entry on noncurrent tasks
2019-10-29 7:19 ` [PATCH v2] " Jiri Slaby
2019-10-29 13:35 ` Josh Poimboeuf
@ 2019-10-30 6:09 ` Jiri Slaby
2019-10-30 7:25 ` [PATCH v3] " Jiri Slaby
2 siblings, 0 replies; 7+ messages in thread
From: Jiri Slaby @ 2019-10-30 6:09 UTC (permalink / raw)
To: tglx; +Cc: linux-kernel, Josh Poimboeuf
On 29. 10. 19, 8:19, Jiri Slaby wrote:
> --- a/kernel/stacktrace.c
> +++ b/kernel/stacktrace.c
> @@ -298,7 +299,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
Argh, "task" here and:
> struct stack_trace trace = {
> .entries = store,
> .max_entries = size,
> - .skip = skipnr + 1,
> + /* skip this function if they are tracing us */
> + .skip = skipnr + !!(current == tsk),
"tsk" here. Scratch this one.
thanks,
--
js
suse labs
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v3] stacktrace: don't skip first entry on noncurrent tasks
2019-10-29 7:19 ` [PATCH v2] " Jiri Slaby
2019-10-29 13:35 ` Josh Poimboeuf
2019-10-30 6:09 ` Jiri Slaby
@ 2019-10-30 7:25 ` Jiri Slaby
2019-11-04 20:24 ` [tip: core/urgent] stacktrace: Don't " tip-bot2 for Jiri Slaby
2 siblings, 1 reply; 7+ messages in thread
From: Jiri Slaby @ 2019-10-30 7:25 UTC (permalink / raw)
To: tglx; +Cc: linux-kernel, Jiri Slaby, Michal Suchanek, Josh Poimboeuf
When doing cat /proc/<PID>/stack, the output is missing the first entry.
When the current code walks the stack starting in stack_trace_save_tsk,
it skips all scheduler functions (that's OK) plus one more function. But
this one function should be skipped only for the 'current' task as it is
stack_trace_save_tsk proper.
The original code (before the common infrastructure) skipped one
function only for the 'current' task -- see save_stack_trace_tsk before
3599fe12a125. So do so also in the new infrastructure now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
Tested-by: Michal Suchanek <msuchanek@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
Notes:
[v2] add the same for the !ARCH_STACKWALK case
[v3] fix build on !ARCH_STACKWALK
kernel/stacktrace.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 6d1f68b7e528..c9ea7eb2cb1a 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
struct stacktrace_cookie c = {
.store = store,
.size = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == tsk),
};
if (!try_get_task_stack(tsk))
@@ -298,7 +299,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
struct stack_trace trace = {
.entries = store,
.max_entries = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == task),
};
save_stack_trace_tsk(task, &trace);
--
2.23.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [tip: core/urgent] stacktrace: Don't skip first entry on noncurrent tasks
2019-10-30 7:25 ` [PATCH v3] " Jiri Slaby
@ 2019-11-04 20:24 ` tip-bot2 for Jiri Slaby
0 siblings, 0 replies; 7+ messages in thread
From: tip-bot2 for Jiri Slaby @ 2019-11-04 20:24 UTC (permalink / raw)
To: linux-tip-commits
Cc: Jiri Slaby, Thomas Gleixner, Michal Suchanek, Josh Poimboeuf,
Ingo Molnar, Borislav Petkov, linux-kernel
The following commit has been merged into the core/urgent branch of tip:
Commit-ID: b0c51f158455e31d5024100cf3580fcd88214b0e
Gitweb: https://git.kernel.org/tip/b0c51f158455e31d5024100cf3580fcd88214b0e
Author: Jiri Slaby <jslaby@suse.cz>
AuthorDate: Wed, 30 Oct 2019 08:25:45 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 04 Nov 2019 21:19:25 +01:00
stacktrace: Don't skip first entry on noncurrent tasks
When doing cat /proc/<PID>/stack, the output is missing the first entry.
When the current code walks the stack starting in stack_trace_save_tsk,
it skips all scheduler functions (that's OK) plus one more function. But
this one function should be skipped only for the 'current' task as it is
stack_trace_save_tsk proper.
The original code (before the common infrastructure) skipped one
function only for the 'current' task -- see save_stack_trace_tsk before
3599fe12a125. So do so also in the new infrastructure now.
Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Suchanek <msuchanek@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20191030072545.19462-1-jslaby@suse.cz
---
kernel/stacktrace.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 6d1f68b..c9ea7eb 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
struct stacktrace_cookie c = {
.store = store,
.size = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == tsk),
};
if (!try_get_task_stack(tsk))
@@ -298,7 +299,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
struct stack_trace trace = {
.entries = store,
.max_entries = size,
- .skip = skipnr + 1,
+ /* skip this function if they are tracing us */
+ .skip = skipnr + !!(current == task),
};
save_stack_trace_tsk(task, &trace);
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-11-04 20:24 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2019-10-25 6:52 [PATCH] stacktrace: don't skip first entry on noncurrent tasks Jiri Slaby
2019-10-25 14:21 ` Josh Poimboeuf
2019-10-29 7:19 ` [PATCH v2] " Jiri Slaby
2019-10-29 13:35 ` Josh Poimboeuf
2019-10-30 6:09 ` Jiri Slaby
2019-10-30 7:25 ` [PATCH v3] " Jiri Slaby
2019-11-04 20:24 ` [tip: core/urgent] stacktrace: Don't " tip-bot2 for Jiri Slaby
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