lkml.org 
[lkml]   [2020]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.9 206/255] futex: Dont enable IRQs unconditionally in put_pi_state()
    Date
    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>

    ---
    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) {

    \
     
     \ /
      Last update: 2020-11-17 14:43    [W:4.255 / U:0.088 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site