Re: [patch V5 03/26] posix-timers: Cure si_sys_private race

[Frederic Weisbecker]

Le Tue, Oct 01, 2024 at 10:42:03AM +0200, Thomas Gleixner a écrit :
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> 
> The si_sys_private member of the siginfo which is embedded in the
> preallocated sigqueue is used by the posix timer code to decide whether a
> timer must be reprogrammed on signal delivery.
> 
> The handling of this is racy as a long standing comment in that code
> documents. It is modified with the timer lock held, but without sighand
> lock being held. The actual signal delivery code checks for it under
> sighand lock without holding the timer lock.
> 
> Hand the new value to send_sigqueue() as argument and store it with sighand
> lock held. This is an intermediate change to address this issue.
> 
> The arguments to this function will be cleanup in subsequent changes.
> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>

Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>