Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

[Jari Ruusu]

Jari Ruusu <jariruusu@protonmail.com> wrote:                                 
>> Sorry to bother you with this question, but subject line mentioned linux 
>> kernel patch (upstream commit 690e47d1403e90b7f2366f03b52ed3304194c793) 
>> seems to be in 6.18.y and 6.12.y kernel branches, but does not seem 
>> be backported to older stable branches such as 6.6.y and 6.1.y . 
>> 
>> To me, that patch you authored seems to be critically important, and 
>> older kernel branches appear to have exact same race, but I am not 
>> an expert on this, so I am asking you. 
>> 
>> Should that "sched/rt: Fix race in push_rt_task" patch be backported 
>> to older stable kernel branches too? 
>> 
>> If, in your opinion, that patch should be backported to older stable 
>> branches, is there any chance of you pinging Greg Kroah-Hartman 
>> and Sasha Levin about it? 
 
Harshit Agarwal <harshit@nutanix.com> wrote:
> Yes, the fix is applicable to older branches that you mentioned.
> In fact I see that they ported my similar fix in the deadline   
> scheduler to 6.1.x and 6.6.x.
>
> If you don't see the rt fix then can you please reach out to them and
> feel free to add me to the thread?
 
Greg, Sasha,
 
Important upstream "sched/rt: Fix race in push_rt_task", commit
690e47d1403e90b7f2366f03b52ed3304194c793, is present in 6.18.y
and 6.12.y kernel branches, but seems to be missing from older
kernel branches.
 
Any chance backporting that race fix to older kernel branches?
 
> BTW, are you seeing this issue on this branch? Just curious.
 
I have not seen that race trigger on any kernel branch.

--
Jari Ruusu  4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD  ACDF F073 3C80 8132 F189

Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

[Greg Kroah-Hartman]

On Wed, Jan 28, 2026 at 07:38:25AM +0000, Jari Ruusu wrote:
> Jari Ruusu <jariruusu@protonmail.com> wrote:                                 
> >> Sorry to bother you with this question, but subject line mentioned linux 
> >> kernel patch (upstream commit 690e47d1403e90b7f2366f03b52ed3304194c793) 
> >> seems to be in 6.18.y and 6.12.y kernel branches, but does not seem 
> >> be backported to older stable branches such as 6.6.y and 6.1.y . 
> >> 
> >> To me, that patch you authored seems to be critically important, and 
> >> older kernel branches appear to have exact same race, but I am not 
> >> an expert on this, so I am asking you. 
> >> 
> >> Should that "sched/rt: Fix race in push_rt_task" patch be backported 
> >> to older stable kernel branches too? 
> >> 
> >> If, in your opinion, that patch should be backported to older stable 
> >> branches, is there any chance of you pinging Greg Kroah-Hartman 
> >> and Sasha Levin about it? 
>  
> Harshit Agarwal <harshit@nutanix.com> wrote:
> > Yes, the fix is applicable to older branches that you mentioned.
> > In fact I see that they ported my similar fix in the deadline   
> > scheduler to 6.1.x and 6.6.x.
> >
> > If you don't see the rt fix then can you please reach out to them and
> > feel free to add me to the thread?
>  
> Greg, Sasha,
>  
> Important upstream "sched/rt: Fix race in push_rt_task", commit
> 690e47d1403e90b7f2366f03b52ed3304194c793, is present in 6.18.y
> and 6.12.y kernel branches, but seems to be missing from older
> kernel branches.
>  
> Any chance backporting that race fix to older kernel branches?

It does not apply cleanly to older kernel branches.  So if it is needed
there, please provide a working backport and we will be glad to consider
it.

thanks,

greg k-h

Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

[Jari Ruusu]

Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > Important upstream "sched/rt: Fix race in push_rt_task", commit
> > 690e47d1403e90b7f2366f03b52ed3304194c793, is present in 6.18.y
> > and 6.12.y kernel branches, but seems to be missing from older
> > kernel branches.
> > 
> > Any chance backporting that race fix to older kernel branches?
> 
> It does not apply cleanly to older kernel branches. So if it is needed
> there, please provide a working backport and we will be glad to consider
> it.

6.12.y backport applies cleanly and works OK for 6.6.y and 6.1.y branches.
I did not test any older branches.

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.12.y&id=debfbc047196df1f6bfd52f2d028c21dce67f0de

--
Jari Ruusu  4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD  ACDF F073 3C80 8132 F189

Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

[Greg Kroah-Hartman]

On Wed, Jan 28, 2026 at 12:02:21PM +0000, Jari Ruusu wrote:
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > > Important upstream "sched/rt: Fix race in push_rt_task", commit
> > > 690e47d1403e90b7f2366f03b52ed3304194c793, is present in 6.18.y
> > > and 6.12.y kernel branches, but seems to be missing from older
> > > kernel branches.
> > > 
> > > Any chance backporting that race fix to older kernel branches?
> > 
> > It does not apply cleanly to older kernel branches. So if it is needed
> > there, please provide a working backport and we will be glad to consider
> > it.
> 
> 6.12.y backport applies cleanly and works OK for 6.6.y and 6.1.y branches.
> I did not test any older branches.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.12.y&id=debfbc047196df1f6bfd52f2d028c21dce67f0de

Can you please send this with your signed-off-by as you have tested it?

thanks,

greg k-h

Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

[Jari Ruusu]

Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> On Wed, Jan 28, 2026 at 12:02:21PM +0000, Jari Ruusu wrote:
> > Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
> > > > Important upstream "sched/rt: Fix race in push_rt_task", commit
> > > > 690e47d1403e90b7f2366f03b52ed3304194c793, is present in 6.18.y
> > > > and 6.12.y kernel branches, but seems to be missing from older
> > > > kernel branches.
> > > > 
> > > > Any chance backporting that race fix to older kernel branches?
> > > 
> > > It does not apply cleanly to older kernel branches. So if it is needed
> > > there, please provide a working backport and we will be glad to consider
> > > it.
> > 
> > 6.12.y backport applies cleanly and works OK for 6.6.y and 6.1.y branches.
> > I did not test any older branches.
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.12.y&id=debfbc047196df1f6bfd52f2d028c21dce67f0de
> 
> Can you please send this with your signed-off-by as you have tested it?

6.12.y backport tested on 6.6.y and 6.1.y branches
Tested-by: Jari Ruusu <jariruusu@protonmail.com>

--
Jari Ruusu  4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD  ACDF F073 3C80 8132 F189

Re: "sched/rt: Fix race in push_rt_task" linux kernel patch backports

[Greg Kroah-Hartman]

On Wed, Jan 28, 2026 at 01:35:13PM +0000, Jari Ruusu wrote:
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > On Wed, Jan 28, 2026 at 12:02:21PM +0000, Jari Ruusu wrote:
> > > Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
> > > > > Important upstream "sched/rt: Fix race in push_rt_task", commit
> > > > > 690e47d1403e90b7f2366f03b52ed3304194c793, is present in 6.18.y
> > > > > and 6.12.y kernel branches, but seems to be missing from older
> > > > > kernel branches.
> > > > > 
> > > > > Any chance backporting that race fix to older kernel branches?
> > > > 
> > > > It does not apply cleanly to older kernel branches. So if it is needed
> > > > there, please provide a working backport and we will be glad to consider
> > > > it.
> > > 
> > > 6.12.y backport applies cleanly and works OK for 6.6.y and 6.1.y branches.
> > > I did not test any older branches.
> > > 
> > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.12.y&id=debfbc047196df1f6bfd52f2d028c21dce67f0de
> > 
> > Can you please send this with your signed-off-by as you have tested it?
> 
> 6.12.y backport tested on 6.6.y and 6.1.y branches
> Tested-by: Jari Ruusu <jariruusu@protonmail.com>

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>