On 2021/3/9 18:41, Greg KH wrote:
On Tue, Mar 09, 2021 at 11:06:02AM +0800, Zheng Yejian wrote:
Lee sent a patchset to update Futex for 4.9, see https://www.spinics.net/lists/stable/msg443081.html, Then Xiaoming sent a follow-up patch for it, see https://lore.kernel.org/lkml/20210225093120.GD641347@dell/.
These patchsets may also resolve following issues in 4.4.260 which have been reported in 4.9, see https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/?h=lin... > /* > * The task is on the way out. When the futex state is > * FUTEX_STATE_DEAD, we know that the task has finished > * the cleanup: > */ > int ret = (p->futex_state = FUTEX_STATE_DEAD) ? -ESRCH : -EAGAIN;
Here may be: int ret = (p->futex_state == FUTEX_STATE_DEAD) ? -ESRCH : -EAGAIN; > raw_spin_unlock_irq(&p->pi_lock); > /* > * If the owner task is between FUTEX_STATE_EXITING and > * FUTEX_STATE_DEAD then store the task pointer and keep > * the reference on the task struct. The calling code will > * drop all locks, wait for the task to reach > * FUTEX_STATE_DEAD and then drop the refcount. This is > * required to prevent a live lock when the current task > * preempted the exiting task between the two states. > */ > if (ret == -EBUSY) And here, the variable "ret" may only be "-ESRCH" or "-EAGAIN", but not "-EBUSY". > *exiting = p; > else > put_task_struct(p);
Since 074e7d515783 ("futex: Ensure the correct return value from futex_lock_pi()") has been merged in 4.4.260, I send the remain 3 patches.
There already are 2 futex patches in the 4.4.y stable queue, do those not resolve these issues for you?
I think that 2 futex patches in 4.4 stable queue are fixing other issues: futex-fix-irq-self-deadlock-and-satisfy-assertion.patch futex-fix-spin_lock-spin_unlock_irq-imbalance.patch But I am not very sure if there are any lock conflicts between that 2 patches and this 3 patches.
If not, please resend this series with the needed git commit ids added to them.
I have add that information and sent a "v2" patchset.