On Tue, 23 Jun 2020 09:38:01 +0900
Masami Hiramatsu wrote:
> On Tue, 23 Jun 2020 08:47:06 +0900
> Masami Hiramatsu wrote:
>
> > On Mon, 22 Jun 2020 09:01:48 -0400
> > Steven Rostedt wrote:
> >
> > > On Mon, 22 Jun 2020 08:27:53 +0800
> > > Ming Lei wrote:
> > >
> > > > Can you kprobe guys
On Tue, 23 Jun 2020 08:47:06 +0900
Masami Hiramatsu wrote:
> On Mon, 22 Jun 2020 09:01:48 -0400
> Steven Rostedt wrote:
>
> > On Mon, 22 Jun 2020 08:27:53 +0800
> > Ming Lei wrote:
> >
> > > Can you kprobe guys improve the implementation for covering this case?
> > > For example, put probe
On Mon, 22 Jun 2020 09:01:48 -0400
Steven Rostedt wrote:
> On Mon, 22 Jun 2020 08:27:53 +0800
> Ming Lei wrote:
>
> > Can you kprobe guys improve the implementation for covering this case?
> > For example, put probe on 3) in case the above situation is recognized.
>
> To do so would require
On Mon, 22 Jun 2020 08:27:53 +0800
Ming Lei wrote:
> Can you kprobe guys improve the implementation for covering this case?
> For example, put probe on 3) in case the above situation is recognized.
To do so would require solving the halting problem.
On Mon, 22 Jun 2020 08:27:53 +0800
Ming Lei wrote:
> I mean it isn't from user's viewpoint, and the binary code is usually a
> black box for final kprobe user.
>
> IMO, all your and Steven's input are just from kprobe/trace developer's
> viewpoint.
> Can you think about the issue from kprobe
Hi Masami,
On Sat, Jun 20, 2020 at 10:37:47AM +0900, Masami Hiramatsu wrote:
> Hi Ming,
>
> On Sat, 20 Jun 2020 07:28:20 +0800
> Ming Lei wrote:
>
> > >
> > > Ah, after all it is as expected. With your kconfig, the kernel is
> > > very agressively optimized.
> > >
> > > $ objdump -dS vmlinux
Hi Ming,
On Sat, 20 Jun 2020 07:28:20 +0800
Ming Lei wrote:
> >
> > Ah, after all it is as expected. With your kconfig, the kernel is
> > very agressively optimized.
> >
> > $ objdump -dS vmlinux | less
> > ...
> > 81256dc3 <__blkdev_put>:
> > {
> > 81256dc3: e8 98 85 df
On Sat, 20 Jun 2020 07:28:20 +0800
Ming Lei wrote:
> Thanks for your investigation.
>
> Some trace tools can just trace on function entry, such as bcc, and some
> user script always trace on function entry.
>
> I guess the issue should belong to kprobe implementation:
The issue is that
Hi Masami,
On Sat, Jun 20, 2020 at 12:35:09AM +0900, Masami Hiramatsu wrote:
> Hi Ming,
>
> On Fri, 19 Jun 2020 21:32:40 +0800
> Ming Lei wrote:
>
> > On Fri, Jun 19, 2020 at 08:19:54AM -0400, Steven Rostedt wrote:
> > > On Fri, 19 Jun 2020 15:28:59 +0800
> > > Ming Lei wrote:
> > >
> > > >
Hi Ming,
On Fri, 19 Jun 2020 21:32:40 +0800
Ming Lei wrote:
> On Fri, Jun 19, 2020 at 08:19:54AM -0400, Steven Rostedt wrote:
> > On Fri, 19 Jun 2020 15:28:59 +0800
> > Ming Lei wrote:
> >
> > > >
> > > > OK, then let's make events (for sure)
> > > >
> > > >
On Fri, Jun 19, 2020 at 08:19:54AM -0400, Steven Rostedt wrote:
> On Fri, 19 Jun 2020 15:28:59 +0800
> Ming Lei wrote:
>
> > >
> > > OK, then let's make events (for sure)
> > >
> > > root@devnote2:/sys/kernel/debug/tracing# echo p __blkdev_put >>
> > > kprobe_events
> > >
On Fri, 19 Jun 2020 15:28:59 +0800
Ming Lei wrote:
> >
> > OK, then let's make events (for sure)
> >
> > root@devnote2:/sys/kernel/debug/tracing# echo p __blkdev_put >>
> > kprobe_events
> > root@devnote2:/sys/kernel/debug/tracing# echo r __blkdev_put >>
> > kprobe_events
> >
Hi Masami,
On Fri, Jun 19, 2020 at 02:12:39PM +0900, Masami Hiramatsu wrote:
> Hi Ming,
>
> On Fri, 19 Jun 2020 07:19:01 +0800
> Ming Lei wrote:
>
> > > I'm using 5.4 on ubuntu and can not reproduce it with kprobe_event.
> > >
> > > root@devnote2:/sys/kernel/tracing# uname -a
> > > Linux
Hi Ming,
On Fri, 19 Jun 2020 07:19:01 +0800
Ming Lei wrote:
> > I'm using 5.4 on ubuntu and can not reproduce it with kprobe_event.
> >
> > root@devnote2:/sys/kernel/tracing# uname -a
> > Linux devnote2 5.4.0-37-generic #41-Ubuntu SMP Wed Jun 3 18:57:02 UTC 2020
> > x86_64 x86_64 x86_64
On Thu, Jun 18, 2020 at 10:56:02PM +0900, Masami Hiramatsu wrote:
> Hi Ming,
>
> On Thu, 18 Jun 2020 20:54:38 +0800
> Ming Lei wrote:
>
> > On Wed, Jun 17, 2020 at 06:30:39PM +0800, Ming Lei wrote:
> > > Hello Guys,
> > >
> > > I found probe on __blkdev_put is missed, which can be observed
> >
Hi Ming,
On Thu, 18 Jun 2020 20:54:38 +0800
Ming Lei wrote:
> On Wed, Jun 17, 2020 at 06:30:39PM +0800, Ming Lei wrote:
> > Hello Guys,
> >
> > I found probe on __blkdev_put is missed, which can be observed
> > via bcc/perf reliably:
> >
> > 1) start trace
> > - perf probe __blkdev_put
> > -
On Wed, Jun 17, 2020 at 06:30:39PM +0800, Ming Lei wrote:
> Hello Guys,
>
> I found probe on __blkdev_put is missed, which can be observed
> via bcc/perf reliably:
>
> 1) start trace
> - perf probe __blkdev_put
> - perf trace -a -e probe:__blkdev_put
>
> or
>
> /usr/share/bcc/tools/stackcount
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