From: Thomas Gleixner tglx@linutronix.de
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.
Fixes: c158b461306df82 ("futex: Cure exit race") Cc: stable@vger.kernel.org # 4.9.258-rc1 Signed-off-by: Xiaoming Ni nixiaoming@huawei.com --- kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index b65dbb5d60bb..0fd785410150 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1207,11 +1207,11 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval, u32 uval2;
/* - * If the futex exit state is not yet FUTEX_STATE_DEAD, wait - * for it to finish. + * If the futex exit state is not yet FUTEX_STATE_DEAD, tell the + * caller that the alleged owner is busy. */ if (tsk && tsk->futex_state != FUTEX_STATE_DEAD) - return -EAGAIN; + return -EBUSY;
/* * Reread the user space value to handle the following situation:
On Mon, Feb 22, 2021 at 08:53:52PM +0800, Xiaoming Ni wrote:
From: Thomas Gleixner tglx@linutronix.de
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.
Fixes: c158b461306df82 ("futex: Cure exit race") Cc: stable@vger.kernel.org # 4.9.258-rc1 Signed-off-by: Xiaoming Ni nixiaoming@huawei.com
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
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@linutronix.de
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@vger.kernel.org # 4.9.258-rc1 Signed-off-by: Xiaoming Ni nixiaoming@huawei.com
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@huawei.com/
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
On Thu, 25 Feb 2021, Xiaoming Ni wrote:
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@linutronix.de
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@vger.kernel.org # 4.9.258-rc1 Signed-off-by: Xiaoming Ni nixiaoming@huawei.com
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@huawei.com/
Replied to the follow-up.
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
linux-stable-mirror@lists.linaro.org
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Greg KH -
Lee Jones -
Xiaoming Ni