On Tue, Mar 09, 2021 at 06:14:37PM +0000, Lee Jones wrote:
> On Tue, 09 Mar 2021, Greg KH wrote:
>
> > On Tue, Mar 09, 2021 at 11:06:05AM +0800, Zheng Yejian wrote:
> > > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > >
> > > The handle_exit_race() function is defined in commit 9c3f39860367
> > > ("futex: Cure exit race"), which never returns -EBUSY. This results
> > > in a small piece of dead code in the attach_to_pi_owner() function:
> > >
> > > int ret = handle_exit_race(uaddr, uval, p); /* Never return -EBUSY */
> > > ...
> > > if (ret == -EBUSY)
> > > *exiting = p; /* dead code */
> > >
> > > The return value -EBUSY is added to handle_exit_race() in upsteam
> > > commit ac31c7ff8624409 ("futex: Provide distinct return value when
> > > owner is exiting"). This commit was incorporated into v4.9.255, before
> > > the function handle_exit_race() was introduced, whitout Modify
> > > handle_exit_race().
> > >
> > > To fix dead code, extract the change of handle_exit_race() from
> > > commit ac31c7ff8624409 ("futex: Provide distinct return value when owner
> > > is exiting"), re-incorporated.
> > >
> > > Lee writes:
> > >
> > > This commit takes the remaining functional snippet of:
> > >
> > > ac31c7ff8624409 ("futex: Provide distinct return value when owner is exiting")
> > >
> > > ... and is the correct fix for this issue.
> > >
> > > Fixes: 9c3f39860367 ("futex: Cure exit race")
> > > Cc: stable@xxxxxxxxxxxxxxx # v4.9.258
> > > Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
> > > Reviewed-by: Lee Jones <lee.jones@xxxxxxxxxx>
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > > Signed-off-by: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
> > > ---
> > > kernel/futex.c | 6 +++---
> > > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > Same here, what is the upstream git id?
>
> It doesn't have one as such - it's a part-patch:
>
> > > This commit takes the remaining functional snippet of:
> > >
> > > ac31c7ff8624409 ("futex: Provide distinct return value when owner is exiting")
That wasn't obvious :(
Is this a backport of another patch in the stable tree somewhere?
confused,
greg k-h
