Re: [PATCH] futex: fix dead code in attach_to_pi_owner()
From: Xiaoming Ni
Date: Thu Feb 25 2021 - 03:57:11 EST
On 2021/2/25 16:25, Greg KH wrote:
On Mon, Feb 22, 2021 at 08:53:52PM +0800, Xiaoming Ni wrote:
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
The handle_exit_race() function is defined in commit c158b461306df82
("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.
mainline:
ac31c7ff8624 futex: Provide distinct return value when owner is exiting
Fixes: c158b461306df82 ("futex: Cure exit race")
stable linux-4.9.y
9c3f39860367 futex: Cure exit race
c27f392040e2 futex: Provide distinct return value when owner is exiting
Cc: stable@xxxxxxxxxxxxxxx # 4.9.258-rc1
Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
---
kernel/futex.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
What is the git commit id of this patch in Linus's tree?
Also, what kernel tree(s) is this supposed to go to?
thanks,
greg k-h
.
Sorry, the commit id c158b461306df82 in the patch does not exist in the
linux-stable repository.
The commit ID is from linux-stable-rc.
I corrected the commit id in a subsequent email, and added a branch
label.
https://lore.kernel.org/lkml/20210224100923.51315-1-nixiaoming@xxxxxxxxxx/
Sorry, I forgot to use "--in-reply-to=" when I sent the update patch.
This issue occurs only in the linux-4.9.y branch v4.9.258
Thanks
xiaoming Ni