The following commit has been merged into the locking/urgent branch of tip:

Commit-ID: 1e106aa3509b86738769775969822ffc1ec21bf4 Gitweb: https://git.kernel.org/tip/1e106aa3509b86738769775969822ffc1ec21bf4 Author: Dan Carpenter dan.carpenter@oracle.com AuthorDate: Fri, 06 Nov 2020 11:52:05 +03:00 Committer: Thomas Gleixner tglx@linutronix.de CommitterDate: Mon, 09 Nov 2020 14:30:30 +01:00

futex: Don't enable IRQs unconditionally in put_pi_state()

The exit_pi_state_list() function calls put_pi_state() with IRQs disabled and is not expecting that IRQs will be enabled inside the function.

Use the _irqsave() variant so that IRQs are restored to the original state instead of being enabled unconditionally.

Fixes: 153fbd1226fb ("futex: Fix more put_pi_state() vs. exit_pi_state_list() races") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201106085205.GA1159983@mwanda --- kernel/futex.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c index ac32887..00259c7 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -788,8 +788,9 @@ static void put_pi_state(struct futex_pi_state *pi_state) */ if (pi_state->owner) { struct task_struct *owner; + unsigned long flags;

- raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); + raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags); owner = pi_state->owner; if (owner) { raw_spin_lock(&owner->pi_lock); @@ -797,7 +798,7 @@ static void put_pi_state(struct futex_pi_state *pi_state) raw_spin_unlock(&owner->pi_lock); } rt_mutex_proxy_unlock(&pi_state->pi_mutex, owner); - raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); + raw_spin_unlock_irqrestore(&pi_state->pi_mutex.wait_lock, flags); }

if (current->pi_state_cache) {