From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 0A933146A72 for ; Mon, 18 Aug 2025 00:56:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755478576; cv=none; b=Oul6NhPoP9ufMMbbDh9rZXiZOlxR+JCAKu0FOxukncTYFEgf04FHk3LomggiXuFs5T/pq8GdXozxzN4Qs8itTkXBIU2mlKtgn1X0HrlT1rc83hzh2tMhVWvp0In3bXzW0WnrPi+DW4lyev/zGNTR2Y1WvFRJiKB/3AdEJ0BkZc0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755478576; c=relaxed/simple; bh=lQQXRYy245OiG2IPuYscDsZGqJXrQUjtXiEFU+b6U5I=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=pmi776+pnIEq84uDARvziBRQ3PNlwR0dgorxzidn9zxbERASLv2CcUSYK/MyuO2pix0S38sXjrLKP9umaOslSeGZLbUZE4uQYVaYzgpav85dsV8yQsXZmDekYfOrazOWZ8ysyT4og01Ml+pPbWAIvsVX31CzJ9V1FwvJ+vEWD6E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4c4vR92wmSzYQtJ7 for ; Mon, 18 Aug 2025 08:56:05 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 01D611A0359 for ; Mon, 18 Aug 2025 08:56:04 +0800 (CST) Received: from [10.174.179.143] (unknown [10.174.179.143]) by APP4 (Coremail) with SMTP id gCh0CgDnrxAieqJoRB0yEA--.17918S3; Mon, 18 Aug 2025 08:56:03 +0800 (CST) Subject: Re: [PATCH] md/raid5-ppl: Fix invalid context sleep in ppl_io_unit_finished() on PREEMPT_RT To: Yunseong Kim , Song Liu Cc: linux-raid@vger.kernel.org, linux-rt-devel@lists.linux.dev, linux-kernel@vger.kernel.org, "yukuai (C)" References: <20250817113114.1335810-3-ysk@kzalloc.com> From: Yu Kuai Message-ID: Date: Mon, 18 Aug 2025 08:56:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250817113114.1335810-3-ysk@kzalloc.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:gCh0CgDnrxAieqJoRB0yEA--.17918S3 X-Coremail-Antispam: 1UD129KBjvJXoW7CFy5XFW7Wry7Cry7XF1kZrb_yoW8uryUpF WrWF9Iv3WkXrsYqwsFk3WIkrWfta1Igry7Cw45uwn7ArZ8XryxJr17Jr9xGryqqF4xJrW8 Xa4UJa9xCrsxA37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkEb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxk0xIA0c2IEe2xFo4CEbIxvr21lc7CjxVAaw2AF wI0_JF0_Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4 xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1D MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I 0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWU JVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x07UK2N tUUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ Hi, ÔÚ 2025/08/17 19:31, Yunseong Kim дµÀ: > The function ppl_io_unit_finished() uses a local_irq_save()/spin_lock() > sequence. On a PREEMPT_RT enabled kernel, spin_lock() can sleep. Calling it > with interrupts disabled creates an atomic context where sleeping is > forbidden. > What? I believe spin_lock can never sleep. > Ensuring that the interrupt state is managed atomically with the lock > itself. The change is applied to both the 'log->io_list_lock' and > 'ppl_conf->no_mem_stripes_lock' critical sections within the function. > > Signed-off-by: Yunseong Kim > --- > drivers/md/raid5-ppl.c | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c > index 56b234683ee6..650bd59ead72 100644 > --- a/drivers/md/raid5-ppl.c > +++ b/drivers/md/raid5-ppl.c > @@ -553,15 +553,13 @@ static void ppl_io_unit_finished(struct ppl_io_unit *io) > > pr_debug("%s: seq: %llu\n", __func__, io->seq); > > - local_irq_save(flags); > - > - spin_lock(&log->io_list_lock); > + spin_lock_irqsave(&log->io_list_lock, flags); > list_del(&io->log_sibling); > - spin_unlock(&log->io_list_lock); > + spin_unlock_irqrestore(&log->io_list_lock, flags); > > mempool_free(io, &ppl_conf->io_pool); > > - spin_lock(&ppl_conf->no_mem_stripes_lock); > + spin_lock_irqsave(&ppl_conf->no_mem_stripes_lock, flags); Please notice, local_irq_save + spin_lock is the same as spin_lock_irqsave, I don't think your changes have any functonal chagnes. Thanks, Kuai > if (!list_empty(&ppl_conf->no_mem_stripes)) { > struct stripe_head *sh; > > @@ -571,9 +569,7 @@ static void ppl_io_unit_finished(struct ppl_io_unit *io) > set_bit(STRIPE_HANDLE, &sh->state); > raid5_release_stripe(sh); > } > - spin_unlock(&ppl_conf->no_mem_stripes_lock); > - > - local_irq_restore(flags); > + spin_unlock_irqrestore(&ppl_conf->no_mem_stripes_lock, flags); > > wake_up(&conf->wait_for_quiescent); > } >