Re: [PATCH RFC 5/9] futex: Use accessor for hrtimer_sleeper ->task field in waitwake.c
From: André Almeida
Date: Mon Aug 03 2026 - 12:15:20 EST
Em 30/07/2026 21:40, Paul E. McKenney escreveu:
The hrtimer_sleeper structure's ->task field is used as a flag to indicateReviewed-by: André Almeida <andrealmeid@xxxxxxxxxx>
that the associated hrtimer has expired. This means that the hrtimer
handler can be storing to this field while other code is loading from it
to check for expiry. Note that additional races appear for hrtimers that
can be restarted, which could be argued to be a user error. However, that
is no reason to let the compiler introduce additional confusion, and to
this end, the hrtimer_sleeper_task_get() was introduced, use of which also
has the benefit of avoiding open-code access to hrtimer_sleeper innards.
Therefore, apply this accessor to kernel/futex/waitwake.c.
KCSAN located this issue.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Darren Hart <dvhart@xxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: "André Almeida" <andrealmeid@xxxxxxxxxx>
Cc: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxx>