From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 11A541E8856; Thu, 7 Nov 2024 10:14:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730974496; cv=none; b=okwR2INAHm5ywsU5k5m5tVTJe3G5MU2GO3GKs9nrsd/SwYYt7yZHgVGrrjLfT2/2OqRQRzjC+igsBSxiyQ++Ue14Yf/3z2kgIqIXDsc8o11cRBGVyos0sifjZ8dk8+aaG2zOJ04o8j43l+sKws1nqewJ+ejiT81YAi0l7tBsB4M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730974496; c=relaxed/simple; bh=w5g82WZeZTzWD79OqJf1UTmTavO98j4tPfUoxbpEwQg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ckfVaL0tkWSxjZ0I1xjIWBrZl/fSWM8NoEKEM6mxEvij/DA9Sino3wCRo/bq8WjVXvw3komhqSMm6sKAdQZzfyQNa+9gTtXdX78ZBV7jEsnFICh8QczQ0FO7svhSPamkT/+d3pKeyQ8Z4YN2fIQHMrky1ymtGgVn/NosoKGW0bQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Rdhp+9da; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Rdhp+9da" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53F4EC4CED2; Thu, 7 Nov 2024 10:14:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730974495; bh=w5g82WZeZTzWD79OqJf1UTmTavO98j4tPfUoxbpEwQg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rdhp+9daubb7PiW1j9ix67RZN+smC9IvZ+YXxVYxT76Xv22mO9/e47Vicp5aHctle GGL0ZMwC2u4zM2vIg9j8P3jlNrD9/nFtyzftPktwI3GVCQ2gICfpsCe2QTLyV4yb2m ggNGKqt02AqlqyVeD/Xr/z1rZwfWryZuE6lTxL5Ql6tPUX+udDxqcjtrcEN4ATPTjy tSZ3w/sYHEN4R46ejmuapnMYIz9gahX4Vwm2wUUvqTFidPORSnLxy7IDidnwiao2TB G5iBxwBXUOA8NM/g/ud6dPcWIpjBL4D4r5QbmBdQEP6hKL+XW6TDc+cnuBUH3w42Pi CS0RYZKH99rcA== Date: Thu, 7 Nov 2024 11:14:52 +0100 From: Frederic Weisbecker To: Sasha Levin Cc: stable@vger.kernel.org, bsegall@google.com, Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: FAILED: Patch "posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone" failed to apply to v6.1-stable tree Message-ID: References: <20241106021018.179970-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241106021018.179970-1-sashal@kernel.org> Hi, Le Tue, Nov 05, 2024 at 09:10:17PM -0500, Sasha Levin a écrit : > The patch below does not apply to the v6.1-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to . Can you try with this updated version on the failing trees? Thanks. --- >From b5b62a0c48448c4bf7cc0ff8c3f3736ced489939 Mon Sep 17 00:00:00 2001 From: Benjamin Segall Date: Fri, 25 Oct 2024 18:35:35 -0700 Subject: [PATCH] posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone When cloning a new thread, its posix_cputimers are not inherited, and are cleared by posix_cputimers_init(). However, this does not clear the tick dependency it creates in tsk->tick_dep_mask, and the handler does not reach the code to clear the dependency if there were no timers to begin with. Thus if a thread has a cputimer running before clone/fork, all descendants will prevent nohz_full unless they create a cputimer of their own. Fix this by entirely clearing the tick_dep_mask in copy_process(). (There is currently no inherited state that needs a tick dependency) Process-wide timers do not have this problem because fork does not copy signal_struct as a baseline, it creates one from scratch. Fixes: b78783000d5c ("posix-cpu-timers: Migrate to use new tick dependency mask model") Signed-off-by: Ben Segall Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/xm26o737bq8o.fsf@google.com Signed-off-by: Frederic Weisbecker --- include/linux/tick.h | 8 ++++++++ kernel/fork.c | 2 ++ 2 files changed, 10 insertions(+) diff --git a/include/linux/tick.h b/include/linux/tick.h index 9459fef5b857..9701c571a5cf 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -252,12 +252,19 @@ static inline void tick_dep_set_task(struct task_struct *tsk, if (tick_nohz_full_enabled()) tick_nohz_dep_set_task(tsk, bit); } + static inline void tick_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit) { if (tick_nohz_full_enabled()) tick_nohz_dep_clear_task(tsk, bit); } + +static inline void tick_dep_init_task(struct task_struct *tsk) +{ + atomic_set(&tsk->tick_dep_mask, 0); +} + static inline void tick_dep_set_signal(struct task_struct *tsk, enum tick_dep_bits bit) { @@ -291,6 +298,7 @@ static inline void tick_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit) { } static inline void tick_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit) { } +static inline void tick_dep_init_task(struct task_struct *tsk) { } static inline void tick_dep_set_signal(struct task_struct *tsk, enum tick_dep_bits bit) { } static inline void tick_dep_clear_signal(struct signal_struct *signal, diff --git a/kernel/fork.c b/kernel/fork.c index 8dd46baee4c3..09a935724bd9 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -97,6 +97,7 @@ #include #include #include +#include #include #include @@ -2183,6 +2184,7 @@ static __latent_entropy struct task_struct *copy_process( acct_clear_integrals(p); posix_cputimers_init(&p->posix_cputimers); + tick_dep_init_task(p); p->io_context = NULL; audit_set_context(p, NULL); -- 2.46.0