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@linutronix.de
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@vger.kernel.org # v4.9.258 Signed-off-by: Xiaoming Ni nixiaoming@huawei.com Reviewed-by: Lee Jones lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com
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