From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793099881; b=R9r9R/qqX2/eHi05m+DYdC2VMcH21ABdD+yOvP63Rm65wtLt6gdRCDznB9hJlCgeNsC5 IzmJUrYHojw1IcpEzSR+lUCui67SqKMc8GAY+u8r+Ppmci8p8AS5EWIJ8w/GIRa60lXk/ 4DVPljLgw0mXvilvHXkshCnIu+i20G4wU0ZR+yMagts1Z3uxg1E2DGhi5C37HBrKoDucG ts5fx4ZxdmWk+CfwUicXapRy8cAtpoAjvczJ2xGDMh5H+BSx8HhXSXPbAV90ojRGD2k/L Lp8sEI0OcU7gTiYPZK0/WqA5VDX8uHla5kTj/jJf3csrbDz20GW6kfeGuEl5wDRa6ag== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793099881; h=DMARC-Filter:DKIM-Signature:Received:X-MC-Unique: X-Mimecast-MFC-AGG-ID:Received:Received:Received:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To:X-Scanned-By; bh=0urO1S2sMMwM1b64Zw173NbbjAiBQHWHM8jZjx0I7VI=; b=nFHTmEeS88tLbhxZWXWdjlwUfht4xCsR7foGZ+s/vjWV0ZxKWV2rsXNVYbxZGrHigVtn oMwQRDqY5c3odaQnzDMXp7JrFPmNAh9hb5YZmS62WxmYhPEJgrPK1Bp87FMBQJfPxrcj+ N+3DI5pKsPjVNNr2XpHRrTHHRxCP7Ts3XkyGBSirmBktPJGqaI6nhR5vaoBJJgVdpZjLA 5aDP5agVZJUKNdrnR6HXtGm8m7BwgRwiDmKVrxQjaBUd6JdYzu/2JopKjWzmEI8jZrwOR 97ERGmUMP+y8bFGrVSO/btUNkNt1dMIrt9K28F74CF8QFVlZkTW9o5WH4vIced3B8ag== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=iT7kiGdy; arc=none smtp.remote-ip=170.10.133.124 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7980606A31F for ; Tue, 27 Oct 2026 11:18:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E7980606A31F 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, unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=iT7kiGdy DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1793099879; 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=0urO1S2sMMwM1b64Zw173NbbjAiBQHWHM8jZjx0I7VI=; b=iT7kiGdyQJWdhfl55WghpAeigv1YRP/9AE4ivvk2TAeEVMO5wLH8HsaVgHk16vRmff29+0 +362ShANEjsZC8JsH9IKuzGD9cjFBxkABMdxmBl1z09g/feOwtqLkOU4ZzMiglD+uIDwIB +odixqMdXLFd99JEt6DBFqHxNiPNdvs= Received: from mx-prod-mc-05.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-374-wTHgKJVoNquQOpTaugwj1g-1; Tue, 27 Oct 2026 07:17:58 -0400 X-MC-Unique: wTHgKJVoNquQOpTaugwj1g-1 X-Mimecast-MFC-AGG-ID: wTHgKJVoNquQOpTaugwj1g_1793099877 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9E13E1956045; Tue, 27 Oct 2026 11:17:56 +0000 (UTC) Received: from onestero-thinkpadp1gen7.tpbc.csb (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 9EB4030000E7; Tue, 27 Oct 2026 11:17:54 +0000 (UTC) Received: by onestero-thinkpadp1gen7.tpbc.csb (nbSMTP-1.00) for uid 13628 oleg@redhat.com; Tue, 27 Oct 2026 12:17:56 +0100 (CET) Date: Tue, 27 Oct 2026 12:17:53 +0100 From: Oleg Nesterov To: Nickolai Zeldovich Cc: Andrew Morton , Christian Brauner , Thomas Gleixner , "Eric W. Biederman" , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] signal: fix endless loop in complete_signal() during a non-leader exec Message-ID: References: <20261027025055.842038-1-nickolai@csail.mit.edu> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261027025055.842038-1-nickolai@csail.mit.edu> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On 10/26, Nickolai Zeldovich wrote: > > The curr_target walk uses next_thread(), which wraps from the last > thread to ->group_leader on the assumption that the leader is first on > signal->thread_head. de_thread() makes the exec'ing thread, the last > one, the leader before release_task() unlinks the old leader, so a walk > that starts at the old leader stays on the new one if that thread > blocks the signal, and never gets back to curr_target. Oops... Nickolai, thanks, let me think about it. Can't work today, I'll try to write another email tomorrow. Oleg.