On Tue, 23 Feb 2021, Zheng Yejian wrote: > From: Peter Zijlstra <[email protected]> > > commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream. > > Both Geert and DaveJ reported that the recent futex commit: > > c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") > > introduced a problem with setting OWNER_DEAD. We set the bit on an > uninitialized variable and then entirely optimize it away as a > dead-store. > > Move the setting of the bit to where it is more useful. > > Reported-by: Geert Uytterhoeven <[email protected]> > Reported-by: Dave Jones <[email protected]> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Linus Torvalds <[email protected]> > Cc: Paul E. McKenney <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") > Link: > http://lkml.kernel.org/r/[email protected] > Signed-off-by: Ingo Molnar <[email protected]> > Signed-off-by: Zheng Yejian <[email protected]>
Why have you dropped my Reviewed-by? > --- > kernel/futex.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/futex.c b/kernel/futex.c > index b65dbb5d60bb..604d1cb9839d 100644 > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -2424,9 +2424,6 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, > struct futex_q *q, > int err = 0; > > oldowner = pi_state->owner; > - /* Owner died? */ > - if (!pi_state->owner) > - newtid |= FUTEX_OWNER_DIED; > > /* > * We are here because either: > @@ -2484,6 +2481,9 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, > struct futex_q *q, > } > > newtid = task_pid_vnr(newowner) | FUTEX_WAITERS; > + /* Owner died? */ > + if (!pi_state->owner) > + newtid |= FUTEX_OWNER_DIED; > > if (get_futex_value_locked(&uval, uaddr)) > goto handle_fault; -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
