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Biederman" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Hyunwoo Kim Subject: Re: [PATCH v2] posix-cpu-timers: Dequeue per-thread timers before exchange_tids() In-Reply-To: References: Date: Mon, 31 Aug 2026 13:56:07 +0200 Message-ID: <87bjaicxm0.ffs@fw13> MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 96D2614000D X-Stat-Signature: zyq8e54hgpnz5d6d7ygwm98f8axzcxc5 X-HE-Tag: 1788177371-519547 X-HE-Meta: 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 wAca4ss6 QVgEmN6gEvS/aV5vTharGUw2TY7GalO/sv8mI8TEYJAuoCRB5EM2JqFerM07OGfM8PLbqFWXWxYhGUiumuX99jTSl52pMKMHmKtWF4aGx0ubXc79tHckDAAJe70sygz5MR9znQer8yHXj5RYDM91rzgHv2f9PzS2kt6k78mxgh/Lr0tkj40zZgf+6CtlcYM6n0mrm75yATT+4YRRLMmOpluk5pdBcao8mreT1NuX6zZsks3WDG4c9pc9zxZbO1o1IdfQFuQGo86l53z0d+S4TfdSVRd15ycceSbpasmTJeObcK2ip7nqpEBqdmc/Fy8uHizM9 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Aug 26 2026 at 20:41, Hyunwoo Kim wrote: > diff --git a/fs/exec.c b/fs/exec.c > index 745f6eb5279e6..9b2d140bd9f2a 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -1003,6 +1003,18 @@ static int de_thread(struct task_struct *tsk) > * the former thread group leader: > */ > > +#ifdef CONFIG_POSIX_TIMERS > + /* > + * exchange_tids() hands this thread's PID to the old leader, > + * which is reaped right after. The PID lookup in > + * timer_lock_sighand() then fails while the per thread CPU > + * timers are still queued here, so dequeue them first. > + */ > + spin_lock(lock); > + posix_cpu_timers_exit(tsk); > + spin_unlock(lock); > +#endif > + > /* Become a process group leader with the old leader's pid. > * The old leader becomes a thread of the this thread group. > */ Similar to the other issue vs. POSIX timer signals this really wants to be solved in exit() independent of non-leader exec(). Let me have a look.