On Fri, Apr 07, 2017 at 07:26:10PM -0700, Darren Hart wrote: > Peter, I presume there will be a v7 with the u32 change and hopefully a couple > text updates?
Well, tglx already committed these here patches, so no -v7. What I can do however is do a follow up patch that fixes some of the in-code things you mentioned. Something like the below is what I had lying about from your earlier emails; I've not looked to see if there's anything else from your later emails. --- Subject: futex: Small misc fixes.. From: Peter Zijlstra <[email protected]> Date: Fri Apr 7 09:04:07 CEST 2017 Feedback from Darren's review. Reported-by: Darren Hart (VMWare) <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- kernel/futex.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1025,7 +1025,8 @@ static int attach_to_pi_state(u32 __user struct futex_pi_state **ps) { pid_t pid = uval & FUTEX_TID_MASK; - int ret, uval2; + u32 uval2; + int ret; /* * Userspace might have messed up non-PI and PI futexes [3] @@ -1441,6 +1442,11 @@ static int wake_futex_pi(u32 __user *uad if (ret) goto out_unlock; + /* + * This is a point of no return; once we modify the uval there is no + * going back and subsequent operations must not fail. + */ + raw_spin_lock(&pi_state->owner->pi_lock); WARN_ON(list_empty(&pi_state->list)); list_del_init(&pi_state->list); @@ -1452,9 +1458,6 @@ static int wake_futex_pi(u32 __user *uad pi_state->owner = new_owner; raw_spin_unlock(&new_owner->pi_lock); - /* - * We've updated the uservalue, this unlock cannot fail. - */ postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q); out_unlock:
