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

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From: Dan Carpenter <dan.carpenter@oracle.com>

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: 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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ben Hutchings 2021-03-01 18:32:02 +01:00 committed by Greg Kroah-Hartman
parent da1b9ad9f0
commit 69015306e3
1 changed files with 4 additions and 2 deletions
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6
kernel/futex.c
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@ -882,10 +882,12 @@ static void put_pi_state(struct futex_pi_state *pi_state)
* and has cleaned up the pi_state already
*/
if (pi_state->owner) {
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
unsigned long flags;
raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags);
pi_state_update_owner(pi_state, NULL);
rt_mutex_proxy_unlock(&pi_state->pi_mutex);
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) {