diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2019-11-06 22:55:37 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-30 13:32:11 +0100 |
| commit | 095444fad7e35dcd63d0c6b86461d024314e2051 (patch) | |
| tree | e9e82c222301b47d928f19775a32e23cbb9fc90b /kernel/exit.c | |
| parent | 3fe0ed7bd7329e28aca7cdaf7353c6d4778b3d41 (diff) | |
futex: Replace PF_EXITPIDONE with a state
commit 3d4775df0a89240f671861c6ab6e8d59af8e9e41 upstream
The futex exit handling relies on PF_ flags. That's suboptimal as it
requires a smp_mb() and an ugly lock/unlock of the exiting tasks pi_lock in
the middle of do_exit() to enforce the observability of PF_EXITING in the
futex code.
Add a futex_state member to task_struct and convert the PF_EXITPIDONE logic
over to the new state. The PF_EXITING dependency will be cleaned up in a
later step.
This prepares for handling various futex exit issues later.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.149449274@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 65133ebddfad..bda17a76e94f 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -818,16 +818,7 @@ void __noreturn do_exit(long code) */ if (unlikely(tsk->flags & PF_EXITING)) { pr_alert("Fixing recursive fault but reboot is needed!\n"); - /* - * We can do this unlocked here. The futex code uses - * this flag just to verify whether the pi state - * cleanup has been done or not. In the worst case it - * loops once more. We pretend that the cleanup was - * done as there is no way to return. Either the - * OWNER_DIED bit is set by now or we push the blocked - * task into the wait for ever nirwana as well. - */ - tsk->flags |= PF_EXITPIDONE; + futex_exit_done(tsk); set_current_state(TASK_UNINTERRUPTIBLE); schedule(); } @@ -918,12 +909,7 @@ void __noreturn do_exit(long code) * Make sure we are holding no locks: */ debug_check_no_locks_held(); - /* - * We can do this unlocked here. The futex code uses this flag - * just to verify whether the pi state cleanup has been done - * or not. In the worst case it loops once more. - */ - tsk->flags |= PF_EXITPIDONE; + futex_exit_done(tsk); if (tsk->io_context) exit_io_context(tsk); |