From mboxrd@z Thu Jan 1 00:00:00 1970 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 A60411EE019 for ; Sun, 2 Mar 2025 19:36:51 +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=1740944213; cv=none; b=hTA/9zZc6Lfpx9H45zPDQNDNQOOAj/nL67tpVu21gJar3MiIsyrO+wToIGsDcdYp3INQUF2tBigHhfw5jQEX24N3qc7mmelyCB1rW0uAY4k9luxC0b8O8s2/pQ1FJmepn6Jr6LpUv7+/b4UrQ/KjMzss03R96vmDxdohewG3W7M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740944213; c=relaxed/simple; bh=59v/7acbCAwAzZHnQfrmUcEbnZngSTtR+DG+a0iztGA=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=fRCN48bxvKR/lclr6ffQgfhjT64zdSI9Ty/ZUMfdM5caRDPCPlkug7tH0IntgCKLmmm+zHjp2RA1wFEJYboLKONvvw1pIwnzyKENOO195gC0uV/cFCG61V7WApiLKQc+Zzy4X2pIrhZ+V/l3zfzJMaZdKIN1MFWKwm4m4EwCRHM= 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=HFoW7euW; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=sLoS4666; 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="HFoW7euW"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="sLoS4666" Message-ID: <20250302193627.167378648@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1740944209; 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=93tD0GtpcIGIW0gpAOkl8thP4K5eE8qN1mEpJfkAGDw=; b=HFoW7euWwQhoTZf6CFebTcMRgy3Uk/b1SQXeVyh+vr2ECFNO9RWke2aEfGLFi4d74ElvES f9r/T9ikU70vqGdVpwZlmBovLD1+Jr62c4/dyinVvFObmQstVQG4XDia3pK7t5LDCvqnZt DvHLLgR8u9vgvWocohgieEDcOIQfOZ79V0l78JXZ9b47jZ5sQh5Bb2EncF/52JnOqBgHVx sto4GZpE7+DsxqWkS8j7ahrv7rdvsY71HhC3rvngjDqWDkjX6F3SYzdgnrIl2vK0A+oUC+ riNbvKq9cqnMkhzoWgfoRi9n0zj7J3INBoHabm+ZIQ0QMBcvxMFeWMsfnjiTog== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1740944209; 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=93tD0GtpcIGIW0gpAOkl8thP4K5eE8qN1mEpJfkAGDw=; b=sLoS4666GSV4BgRmf2FsmdT/zV0bappJMxwM//EU2Yyw48rqe1qtJBtxaSA3iLPVpe3JM5 M5lElbgeX7T8BvAA== From: Thomas Gleixner To: LKML Cc: Anna-Maria Behnsen , Frederic Weisbecker , Benjamin Segall , Eric Dumazet , Andrey Vagin , Pavel Tikhomirov , Peter Zijlstra Subject: [patch V2 04/17] posix-timers: Remove a few paranoid warnings References: <20250302185753.311903554@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Sun, 2 Mar 2025 20:36:49 +0100 (CET) Warnings about a non-initialized timer or non-existing callbacks are just useful for implementing new posix clocks, but there a NULL pointer dereference is expected anyway. :) Signed-off-by: Thomas Gleixner --- V2: New patch --- kernel/time/posix-timers.c | 37 ++++++++----------------------------- 1 file changed, 8 insertions(+), 29 deletions(-) --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -675,7 +675,6 @@ void common_timer_get(struct k_itimer *t static int do_timer_gettime(timer_t timer_id, struct itimerspec64 *setting) { - const struct k_clock *kc; struct k_itimer *timr; unsigned long flags; int ret = 0; @@ -685,11 +684,7 @@ static int do_timer_gettime(timer_t time return -EINVAL; memset(setting, 0, sizeof(*setting)); - kc = timr->kclock; - if (WARN_ON_ONCE(!kc || !kc->timer_get)) - ret = -EINVAL; - else - kc->timer_get(timr, setting); + timr->kclock->timer_get(timr, setting); unlock_timer(timr, flags); return ret; @@ -817,7 +812,6 @@ static void common_timer_wait_running(st static struct k_itimer *timer_wait_running(struct k_itimer *timer, unsigned long *flags) { - const struct k_clock *kc = READ_ONCE(timer->kclock); timer_t timer_id = READ_ONCE(timer->it_id); /* Prevent kfree(timer) after dropping the lock */ @@ -828,8 +822,7 @@ static struct k_itimer *timer_wait_runni * kc->timer_wait_running() might drop RCU lock. So @timer * cannot be touched anymore after the function returns! */ - if (!WARN_ON_ONCE(!kc->timer_wait_running)) - kc->timer_wait_running(timer); + timer->kclock->timer_wait_running(timer); rcu_read_unlock(); /* Relock the timer. It might be not longer hashed. */ @@ -892,7 +885,6 @@ static int do_timer_settime(timer_t time struct itimerspec64 *new_spec64, struct itimerspec64 *old_spec64) { - const struct k_clock *kc; struct k_itimer *timr; unsigned long flags; int error; @@ -915,11 +907,7 @@ static int do_timer_settime(timer_t time /* Prevent signal delivery and rearming. */ timr->it_signal_seq++; - kc = timr->kclock; - if (WARN_ON_ONCE(!kc || !kc->timer_set)) - error = -EINVAL; - else - error = kc->timer_set(timr, tmr_flags, new_spec64, old_spec64); + error = timr->kclock->timer_set(timr, tmr_flags, new_spec64, old_spec64); if (error == TIMER_RETRY) { // We already got the old time... @@ -1001,18 +989,6 @@ static inline void posix_timer_cleanup_i } } -static inline int timer_delete_hook(struct k_itimer *timer) -{ - const struct k_clock *kc = timer->kclock; - - /* Prevent signal delivery and rearming. */ - timer->it_signal_seq++; - - if (WARN_ON_ONCE(!kc || !kc->timer_del)) - return -EINVAL; - return kc->timer_del(timer); -} - /* Delete a POSIX.1b interval timer. */ SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) { @@ -1025,7 +1001,10 @@ SYSCALL_DEFINE1(timer_delete, timer_t, t if (!timer) return -EINVAL; - if (unlikely(timer_delete_hook(timer) == TIMER_RETRY)) { + /* Prevent signal delivery and rearming. */ + timer->it_signal_seq++; + + if (unlikely(timer->kclock->timer_del(timer) == TIMER_RETRY)) { /* Unlocks and relocks the timer if it still exists */ timer = timer_wait_running(timer, &flags); goto retry_delete; @@ -1071,7 +1050,7 @@ static void itimer_delete(struct k_itime * mechanism. Worse, that timer mechanism might run the expiry * function concurrently. */ - if (timer_delete_hook(timer) == TIMER_RETRY) { + if (timer->kclock->timer_del(timer) == TIMER_RETRY) { /* * Timer is expired concurrently, prevent livelocks * and pointless spinning on RT.