| Message ID | 20170613173308.6653-2-dustinb@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jun 13, 2017 at 10:33:08AM -0700, Dustin Brown wrote: > To aid in debugging driver modules, export save_stack_trace_tsk() for > the ARM64 architecture. > --- > arch/arm64/kernel/stacktrace.c | 1 + > 1 file changed, 1 insertion(+) Please can you repost with your Signed-off-by line added to the patch? I can't merge anything from you without that. Thanks, Will > diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c > index feac80c22f61..09d37d66b630 100644 > --- a/arch/arm64/kernel/stacktrace.c > +++ b/arch/arm64/kernel/stacktrace.c > @@ -210,6 +210,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) > > put_task_stack(tsk); > } > +EXPORT_SYMBOL_GPL(save_stack_trace_tsk); > > void save_stack_trace(struct stack_trace *trace) > { > -- > 2.12.2 >
On Tue, Jun 13, 2017 at 06:44:06PM +0100, Will Deacon wrote: > On Tue, Jun 13, 2017 at 10:33:08AM -0700, Dustin Brown wrote: > > To aid in debugging driver modules, export save_stack_trace_tsk() for > > the ARM64 architecture. > > --- > > arch/arm64/kernel/stacktrace.c | 1 + > > 1 file changed, 1 insertion(+) > > Please can you repost with your Signed-off-by line added to the patch? I > can't merge anything from you without that. I think it would also be a good thing to have a little more information about how this is being used in driver modules. If it's for ad-hoc debugging, then I see no reason for it to be merged into mainline kernels just for the utility of people adding code to drivers to perform that debug - they might as well temporarily add the export at the same time IMHO.
On Tue, Jun 13, 2017 at 07:16:03PM +0100, Russell King - ARM Linux wrote: > On Tue, Jun 13, 2017 at 06:44:06PM +0100, Will Deacon wrote: > > On Tue, Jun 13, 2017 at 10:33:08AM -0700, Dustin Brown wrote: > > > To aid in debugging driver modules, export save_stack_trace_tsk() for > > > the ARM64 architecture. > > > --- > > > arch/arm64/kernel/stacktrace.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > Please can you repost with your Signed-off-by line added to the patch? I > > can't merge anything from you without that. > > I think it would also be a good thing to have a little more information > about how this is being used in driver modules. That would certainly help to motivate the change; I was just going by the fact that most other architectures export this symbol and therefore it is assumedly useful to somebody. > If it's for ad-hoc debugging, then I see no reason for it to be merged > into mainline kernels just for the utility of people adding code to > drivers to perform that debug - they might as well temporarily add the > export at the same time IMHO. A quick look at the Debian archive suggests that it's used by "systemtap" (although this seems to be part of an autoconf helper) and "kpatch". Dustin -- do you have another use-case behind this? Will
Hi Will, I sent out updated patches yesterday with better descriptions, but I am not sure I got the threads associated correctly. We have a dynamically loaded kernel driver with a worker thread which processes a queue. From time to time, defects get introduced that cause this thread to hang for long periods of time, or deadlock. To catch these quickly, we introduced a watchdog timer that does a bug-on when individual work items take longer than some threshold. This works great when the worker thread is on the CPU at the point of timeout, but in cases where it went to sleep on a mutex or a kmalloc, we want to dump the worker thread's stack trace specifically. This is code that is expected to live for years, and is not a one-off debugging instance. Thanks, -Dustin -----Original Message----- From: Will Deacon [mailto:will.deacon@arm.com] Sent: Wednesday, June 14, 2017 3:07 AM To: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Dustin Brown <dustinb@codeaurora.org>; catalin.marinas@arm.com; linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/2] arm64: Export save_stack_trace_tsk() On Tue, Jun 13, 2017 at 07:16:03PM +0100, Russell King - ARM Linux wrote: > On Tue, Jun 13, 2017 at 06:44:06PM +0100, Will Deacon wrote: > > On Tue, Jun 13, 2017 at 10:33:08AM -0700, Dustin Brown wrote: > > > To aid in debugging driver modules, export save_stack_trace_tsk() > > > for the ARM64 architecture. > > > --- > > > arch/arm64/kernel/stacktrace.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > Please can you repost with your Signed-off-by line added to the > > patch? I can't merge anything from you without that. > > I think it would also be a good thing to have a little more > information about how this is being used in driver modules. That would certainly help to motivate the change; I was just going by the fact that most other architectures export this symbol and therefore it is assumedly useful to somebody. > If it's for ad-hoc debugging, then I see no reason for it to be merged > into mainline kernels just for the utility of people adding code to > drivers to perform that debug - they might as well temporarily add the > export at the same time IMHO. A quick look at the Debian archive suggests that it's used by "systemtap" (although this seems to be part of an autoconf helper) and "kpatch". Dustin -- do you have another use-case behind this? Will
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index feac80c22f61..09d37d66b630 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -210,6 +210,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) put_task_stack(tsk); } +EXPORT_SYMBOL_GPL(save_stack_trace_tsk); void save_stack_trace(struct stack_trace *trace) {