From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 DBD764A3F3A for ; Mon, 21 Sep 2026 14:26:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790000784; cv=none; b=PPnpH0ExYtY6EdxLI0IRRjGXUlKz+ozeenKKA6j2iE6JfpzVbCHn2vnxM75lgBiDYM9UllsSEJEZA6EYIxAYKAnT9ZsHvgrdTJskTuH+pnIt4XS8gzjd4XYAvyOg1Ff+LPOBzxXetg3eWPn0ju5EPU85toTrziWuWLftMfJumMc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790000784; c=relaxed/simple; bh=MyEXqmotfUt4yA1+Hy68CC39XSg+h8EY6D6AQC+ntwk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IYUXVjzYzrO9m4q04C1HWmVm5q4fBQYZXNOuDRRlYLaGissy2WVJ/HrNNKnrCnyrpigLkW37j+0VdGODoQQRh1psASmRGOMla3Aw6To2RMC0hq3xZBx2XYWZHuFPCoUrVCEaeHbb89fiMcV1CO/ZOHgPZcv5vgxzcfWzr4EWNvc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=NnUcfUbY; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NnUcfUbY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1790000781; 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: in-reply-to:in-reply-to:references:references; bh=+pcLJlj5TIE0odij7lPFRE58kbHckgF1Zqih4BUaQQ8=; b=NnUcfUbYrAdUlQ2OB6A+tnSnSIfM0d9/bfEDSbNGckENS2my0FEYEuo6API0Ekb5EklLtL mgvTpNtnHj+z3lny4WVi8HxN2PUMIlm+5d6rtjW5TKqMXx2sVe6oq22HMt+/2C+5+5n3zi PzAAK/TvPgRmi9vti29WhJTxbESwi04= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-48-zIc0_6r3NoSA_cJqD0Vc_A-1; Mon, 21 Sep 2026 10:26:18 -0400 X-MC-Unique: zIc0_6r3NoSA_cJqD0Vc_A-1 X-Mimecast-MFC-AGG-ID: zIc0_6r3NoSA_cJqD0Vc_A_1790000776 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 422C11953994; Mon, 21 Sep 2026 14:26:15 +0000 (UTC) Received: from fedora (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 5D11B41D; Mon, 21 Sep 2026 14:26:11 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 21 Sep 2026 16:26:14 +0200 (CEST) Date: Mon, 21 Sep 2026 16:26:09 +0200 From: Oleg Nesterov To: Christian Brauner Cc: Chris Mason , linux-fsdevel@vger.kernel.org, Jens Axboe , Alexander Viro , Jan Kara , NeilBrown , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, io-uring@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v3 14/17] fork: don't create io threads once PF_POSTCOREDUMP is set Message-ID: References: <20260921-work-coredump-fixes-v3-0-8e4adb1619e6@kernel.org> <20260921-work-coredump-fixes-v3-14-8e4adb1619e6@kernel.org> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260921-work-coredump-fixes-v3-14-8e4adb1619e6@kernel.org> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 On 09/21, Christian Brauner wrote: > > Refuse to create an io thread when the creator has PF_POSTCOREDUMP. > That costs nothing. io_uring_files_cancel() raises IO_WQ_BIT_EXIT > before it runs any task work, so a worker created from there only ever > gets to exit again, and io_should_retry_thread() doesn't retry -EINTR. Thanks for this note in the changelog, > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -2706,8 +2706,8 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) > .user_worker = 1, > }; > > - /* A creator past its fatal signal gets no thread. */ > - if (current->flags & PF_SIGNALED) > + /* A creator past its fatal signal or its coredump point gets no thread. */ > + if (current->flags & (PF_SIGNALED | PF_POSTCOREDUMP)) > return ERR_PTR(-EINTR); Acked-by: Oleg Nesterov