Re: [PATCH 2/2] x86/tbl/trace: Do not trace on CPU that is offline

Sedat Dilek
2015-02-07T20:14:22Z

On Sat, Feb 7, 2015 at 9:09 PM, Paul E. McKenney
<paulmck@linux.vnet.ibm.com> wrote:
> On Sat, Feb 07, 2015 at 10:20:02AM -0500, Steven Rostedt wrote:
>> On Sat, 7 Feb 2015 09:01:34 +0100
>> Sedat Dilek <sedat.dilek@gmail.com> wrote:
>>
>>
>> > - Tested-by's
>> > - Reference of 2/2 to 1/2
>>
>> The two are together in the series and fix two different bugs. They do
>> not need to reference each other.
>>
>> > - CC: stable v3.17+/v3.18+ ? (1/2 has a hint for backporting in case
>> > of 3.17+ which is BTW EOL, not sure if there are main distros
>> > supporting linux-3.17.y)
>>
>> The first patch fixes a bug introduced in 3.18. There would be no splat
>> in 3.17 because the check didn't exist then. But the RCU reference
>> while cpu offline (second bug) was introduced in 3.17 and that is what
>> the second patch fixes.
>>
>> >
>> > BTW, do you happen to know if there is a someting like a
>> > "Requires-tag" or "Precondition-tag" (for example the Fixes-tag is
>> > very helpful)?
>>
>> We don't need more tags.
>>
>> > AFAICS people place such information into the commit-message.
>> > I have seen "References:" but this is more to point to a
>> > bug-tracking-system (BTS).
>> >
>> > EXAMPLE:
>> >
>> > commit 63b03e2d2477586440741677ecac45bcf28d7b1
>> > "mutex: Always clear owner field upon mutex_unlock()"
>> >
>> > References: https://bugs.freedesktop.org/show_bug.cgi?id=87955
>> >
>>
>> I may add that, but more appropriate would be to add the commit that
>> fixes the bug to the bug report.
>>
>> > Maybe ask godfather of SubmittingPatches greg-kh?
>>
>> Heh, I haven't read that document in years.
>
> Given my confusion about stable tags, I read stable_kernel_rules.txt
> the other day, and found this:
>
> - If the patch requires other patches as prerequisites which can be
> cherry-picked, then this can be specified in the following format in
> the sign-off area:
>
> Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle
> Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle
> Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic
> Cc: <stable@vger.kernel.org> # 3.3.x
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
> The tag sequence has the meaning of:
> git cherry-pick a1f84a3
> git cherry-pick 1b9508f
> git cherry-pick fd21073
> git cherry-pick <this commit>
>
> Does that do what you need?
>

( Bah, I had a look recently into rules.txt in stable-queue.git. )
That sounds cool and is what I wanted.

Thanks, Paul!

- Sedat -

[1] http://git.kernel.org/cgit/linux/kernel/git/stable/stable-queue.git/tree/rules.txt