From nobody Mon Nov 25 02:45:14 2024 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E0BD61BDA9B for ; Thu, 31 Oct 2024 15:46:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730389599; cv=none; b=s2sCQdSvBAsGLxdQ6FXEPID06zI1BKhHerYkATxRGzxtKlomf9hh1sZfxB5OmO7FXs5cTVlVskhDI6cJhg6tvN0Nfe7pQOuKmj3aSs/mUSKiwT0N2/Y3vqWd5Pane6oTH8K/aOXmS2vBo6ZTzj86lfg0WkRBX3p/tCtgtV/Fvvc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730389599; c=relaxed/simple; bh=W9vkcg3goHw3toa/NPatBgcGiFKl03A2/EGpx0AvsdE=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=RFwWH3wUZXN1Z+xy7WlAM3eGPug5tAkxju4meL2fYFQgjBMa1is7qXYxGYpWd2m9kKQOvMpkXUnH4pMwrdSMnD/URsBFjDjW/ZqpLcb1aibMYrLkDHrEItKxzQlb7ikzPI1k+4HhCEmWLatPBQIEPhEiF30iPsK0cENva1kGZeA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=nKhDVGre; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=SPJWRAbv; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="nKhDVGre"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="SPJWRAbv" Message-ID: <20241031154425.182629074@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1730389595; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=I2JKYlpS9EROm2PXQHeSksdbFrfFm6VApPBBZM9ycE4=; b=nKhDVGreMefqEU/ghR9JuGellFhk+cHje4Q2CTYAtmlhb3tQo689wfjKWL0nd5MKgygK2V CQ4DFKP/7cyr7WW9bih4YUIoHOAdNPqoKsxR4BPvpmnGgukMrH93AprLZEyzhz5TJFguhn yC7wAVuMG/+mZIufqGtHb6WBC2VNx7TF0e5j0wr8r4944RAnpy2NAy0q55ORnF72bt3MLP o88xM/DnC1T8ACTijCogiQysUE5xC3cSCo8Tjq9TLm2zBGswoY7HI7qIePH2EDbkhER3t7 QyAeTwrTUNgd/i2eKhC0Z5d/iqvRWy4vAwDp8Hs6bN/PHSvZjlnclMNkLqHK8g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1730389595; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=I2JKYlpS9EROm2PXQHeSksdbFrfFm6VApPBBZM9ycE4=; b=SPJWRAbvjNxaZNeRvMUKFxQj80GpjFr6+4bkZ82NY6Xh32w+D+4+9+/c3W9KtEAbyi9Oxt NU1Y1JY0/uR0RhDg== From: Thomas Gleixner To: LKML Cc: Anna-Maria Behnsen , Frederic Weisbecker , John Stultz , Peter Zijlstra , Ingo Molnar , Stephen Boyd , Eric Biederman , Oleg Nesterov Subject: [patch v6 10/20] signal: Replace resched_timer logic References: <20241031151625.361697424@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Thu, 31 Oct 2024 16:46:35 +0100 (CET) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner In preparation for handling ignored posix timer signals correctly and embedding the sigqueue struct into struct k_itimer, hand down a pointer to the sigqueue struct into posix_timer_deliver_signal() instead of just having a boolean flag. No functional change. Suggested-by: Eric W. Biederman Signed-off-by: Thomas Gleixner Acked-by: "Eric W. Biederman" Reviewed-by: Frederic Weisbecker --- V6: NULLify timer_sigq after again: in dequeue_signal() - Frederic V5: New patch --- include/linux/posix-timers.h | 5 +++-- kernel/signal.c | 32 ++++++++++++++++++++------------ kernel/time/posix-timers.c | 2 +- 3 files changed, 24 insertions(+), 15 deletions(-) --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -110,7 +110,7 @@ static inline void posix_cputimers_rt_wa void posixtimer_rearm_itimer(struct task_struct *p); bool posixtimer_init_sigqueue(struct sigqueue *q); int posixtimer_send_sigqueue(struct k_itimer *tmr); -bool posixtimer_deliver_signal(struct kernel_siginfo *info); +bool posixtimer_deliver_signal(struct kernel_siginfo *info, struct sigqueu= e *timer_sigq); void posixtimer_free_timer(struct k_itimer *timer); =20 /* Init task static initializer */ @@ -135,7 +135,8 @@ static inline void posix_cputimers_init( static inline void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit) { } static inline void posixtimer_rearm_itimer(struct task_struct *p) { } -static inline bool posixtimer_deliver_signal(struct kernel_siginfo *info) = { return false; } +static inline bool posixtimer_deliver_signal(struct kernel_siginfo *info, + struct sigqueue *timer_sigq) { return false; } static inline void posixtimer_free_timer(struct k_itimer *timer) { } #endif =20 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -545,7 +545,7 @@ bool unhandled_signal(struct task_struct } =20 static void collect_signal(int sig, struct sigpending *list, kernel_siginf= o_t *info, - bool *resched_timer) + struct sigqueue **timer_sigq) { struct sigqueue *q, *first =3D NULL; =20 @@ -568,10 +568,17 @@ static void collect_signal(int sig, stru list_del_init(&first->list); copy_siginfo(info, &first->info); =20 - *resched_timer =3D (first->flags & SIGQUEUE_PREALLOC) && - (info->si_code =3D=3D SI_TIMER); - - __sigqueue_free(first); + /* + * posix-timer signals are preallocated and freed when the + * timer goes away. Either directly or by clearing + * SIGQUEUE_PREALLOC so that the next delivery will free + * them. Spare the extra round through __sigqueue_free() + * which is ignoring preallocated signals. + */ + if (unlikely((first->flags & SIGQUEUE_PREALLOC) && (info->si_code =3D=3D= SI_TIMER))) + *timer_sigq =3D first; + else + __sigqueue_free(first); } else { /* * Ok, it wasn't in the queue. This must be @@ -588,12 +595,12 @@ static void collect_signal(int sig, stru } =20 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, - kernel_siginfo_t *info, bool *resched_timer) + kernel_siginfo_t *info, struct sigqueue **timer_sigq) { int sig =3D next_signal(pending, mask); =20 if (sig) - collect_signal(sig, pending, info, resched_timer); + collect_signal(sig, pending, info, timer_sigq); return sig; } =20 @@ -605,18 +612,19 @@ static int __dequeue_signal(struct sigpe int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *= type) { struct task_struct *tsk =3D current; - bool resched_timer =3D false; + struct sigqueue *timer_sigq; int signr; =20 lockdep_assert_held(&tsk->sighand->siglock); =20 again: *type =3D PIDTYPE_PID; - signr =3D __dequeue_signal(&tsk->pending, mask, info, &resched_timer); + timer_sigq =3D NULL; + signr =3D __dequeue_signal(&tsk->pending, mask, info, &timer_sigq); if (!signr) { *type =3D PIDTYPE_TGID; signr =3D __dequeue_signal(&tsk->signal->shared_pending, - mask, info, &resched_timer); + mask, info, &timer_sigq); =20 if (unlikely(signr =3D=3D SIGALRM)) posixtimer_rearm_itimer(tsk); @@ -642,8 +650,8 @@ int dequeue_signal(sigset_t *mask, kerne current->jobctl |=3D JOBCTL_STOP_DEQUEUED; } =20 - if (IS_ENABLED(CONFIG_POSIX_TIMERS) && unlikely(resched_timer)) { - if (!posixtimer_deliver_signal(info)) + if (IS_ENABLED(CONFIG_POSIX_TIMERS) && unlikely(timer_sigq)) { + if (!posixtimer_deliver_signal(info, timer_sigq)) goto again; } =20 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -254,7 +254,7 @@ static void common_hrtimer_rearm(struct * This function is called from the signal delivery code. It decides * whether the signal should be dropped and rearms interval timers. */ -bool posixtimer_deliver_signal(struct kernel_siginfo *info) +bool posixtimer_deliver_signal(struct kernel_siginfo *info, struct sigqueu= e *timer_sigq) { struct k_itimer *timr; unsigned long flags;