On 2021/2/22 18:16, Greg KH wrote:
On Mon, Feb 22, 2021 at 03:03:28PM +0800, Xiaoming Ni wrote:
From: Thomas Gleixner<tglx@xxxxxxxxxxxxx>
commit ac31c7ff8624409ba3c4901df9237a616c187a5d upstream.
This commit is already in the 4.9 tree. If the backport was incorrect,
say that here, and describe what went wrong and why this commit fixes
it.
Also state what commit this fixes as well, otherwise this changelog just
looks like it is being applied again to the tree, which doesn't make
much sense.
thanks,
greg k-h
.
I wrote a cover for it. but forgot to adjust the title of the cover:
https://lore.kernel.org/lkml/20210222070328.102384-1-nixiaoming@xxxxxxxxxx/
I found a dead code in the queue/4.9 branch of the stable-rc repository.
2021-02-03:
commit c27f392040e2f6 ("futex: Provide distinct return value when
owner is exiting")
The function handle_exit_race does not exist. Therefore, the
change in handle_exit_race() is ignored in the patch round.
2021-02-22:
commit e55cb811e612 ("futex: Cure exit race")
Define the handle_exit_race() function,
but no branch in the function returns EBUSY.
As a result, dead code occurs in the attach_to_pi_owner():
int ret = handle_exit_race(uaddr, uval, p);
...
if (ret == -EBUSY)
*exiting = p; /* dead code */
To fix the dead code, modify the commit e55cb811e612 ("futex: Cure exit
race"),
or install a patch to incorporate the changes in handle_exit_race().
I am unfamiliar with the processing of the stable-rc queue branch,
and I cannot find the patch mail of the current branch in
https://lore.kernel.org/lkml/?q=%22futex%3A+Cure+exit+race%22
Therefore, I re-integrated commit ac31c7ff8624 ("futex: Provide distinct
return value when owner is exiting").
And wrote a cover (but forgot to adjust the title of the cover):
https://lore.kernel.org/lkml/20210222070328.102384-1-nixiaoming@xxxxxxxxxx/
Thanks
Xiaoming Ni
