This is a note to let you know that I've just added the patch titled
futex: Don't enable IRQs unconditionally in put_pi_state()
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
futex-don-t-enable-irqs-unconditionally-in-put_pi_state.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1e106aa3509b86738769775969822ffc1ec21bf4 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Fri, 6 Nov 2020 11:52:05 +0300
Subject: futex: Don't enable IRQs unconditionally in put_pi_state()
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20201106085205.GA1159983@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/futex.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -788,8 +788,9 @@ static void put_pi_state(struct futex_pi
*/
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
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) {
Patches currently in stable-queue which might be from dan.carpenter@xxxxxxxxxx are
queue-5.9/alsa-hda-prevent-undefined-shift-in-snd_hdac_ext_bus.patch
queue-5.9/ext4-unlock-xattr_sem-properly-in-ext4_inline_data_truncate.patch
queue-5.9/can-peak_usb-add-range-checking-in-decode-operations.patch
queue-5.9/futex-don-t-enable-irqs-unconditionally-in-put_pi_state.patch
