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Commit 364ec3d2 authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
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UPSTREAM: futex: Don't enable IRQs unconditionally in put_pi_state() 



commit 1e106aa3509b86738769775969822ffc1ec21bf4 upstream.

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: 153fbd12 ("futex: Fix more put_pi_state() vs. exit_pi_state_list() races")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201106085205.GA1159983@mwanda


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 2192d905)
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
Change-Id: I10bc011b54ffc6d66c0a499ecebfa5b2d96d58ce
parent 6f8f2dc7

kernel/futex.c

+3 −2
Original line number Diff line number Diff line
@@ -881,8 +881,9 @@ 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);
@@ -890,7 +891,7 @@ 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) {