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 0F1F72561D7 for ; Tue, 25 Mar 2025 13:04:59 +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=1742907901; cv=none; b=MKyw3Q/ISrcXSphthD2lhnqW1DfARJxEoiG78cL+23OQrG9/9HojRGAdYi0LqmcMrWQ6k3QZsVimQn90XKUMkQV6J6/2B68aef1PidOxg0zmPb5QMrQDzLRC5u/kunM2rcb+QntUHE7k8TEkGem98mKYLDsAcm6OuBZhmTMvd4c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742907901; c=relaxed/simple; bh=KtXukF7zS507yXC0bV3Lgtc0k1fuYoFUyPiii35Srw4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Jhq4KWTPWk9AHAU10e9Rs9Seum4Z1f4/qRbQ3nIPCFzJMdYqfHYOFw5ZhSTq4Pr6E8wpnvF0CCz091u1pEL0/CGbjMGIO1hDUkG+z1WhSRmQTEdUg3Ym9bx7UTa6VOusIocXDaCW9yEyvdXfXFWy2rieWwAAJF4Wfj8ga5YxB1A= 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=WUQL2t3f; 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="WUQL2t3f" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742907899; 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=a717aorAR0FFD6ZXSPKWzRFsANFSqFlPrG/xcqr9NTM=; b=WUQL2t3fHBzpdTIWsy+4S14oRQY7JR1Oxld2hSBnumeLgDu+SzA/6Xt/adsIIMiYI5XCQH fGrZA2BiLmBMlyAlkSoZInHczKrsVZQH9MxMxUxyK1gEGxZhGLlLTniZ8XBkL/blyHC43J tjq494Pr30BVnz+D64xl7J01vfRRDc0= 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-688-ONqfwzWAMceN_6i1pbI_rA-1; Tue, 25 Mar 2025 09:04:54 -0400 X-MC-Unique: ONqfwzWAMceN_6i1pbI_rA-1 X-Mimecast-MFC-AGG-ID: ONqfwzWAMceN_6i1pbI_rA_1742907891 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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 E66D21956067; Tue, 25 Mar 2025 13:04:50 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.42]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 719BF19541A5; Tue, 25 Mar 2025 13:04:44 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 25 Mar 2025 14:04:17 +0100 (CET) Date: Tue, 25 Mar 2025 14:04:10 +0100 From: Oleg Nesterov To: K Prateek Nayak , Eric Van Hensbergen , Latchesar Ionkov , Dominique Martinet , Christian Schoenebeck Cc: Mateusz Guzik , syzbot , brauner@kernel.org, dhowells@redhat.com, jack@suse.cz, jlayton@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netfs@lists.linux.dev, swapnil.sapkal@amd.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, v9fs@lists.linux.dev Subject: Re: [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter Message-ID: <20250325130410.GA10828@redhat.com> References: <67e05e30.050a0220.21942d.0003.GAE@google.com> <20250323194701.GC14883@redhat.com> <20250323210251.GD14883@redhat.com> <7e377feb-a78b-4055-88cc-2c20f924bf82@amd.com> <20250325121526.GA7904@redhat.com> Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250325121526.GA7904@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On 03/25, K Prateek Nayak wrote: > > I chased this down to p9_client_rpc() net/9p/client.c specifically: > > err = c->trans_mod->request(c, req); > if (err < 0) { > /* write won't happen */ > p9_req_put(c, req); > if (err != -ERESTARTSYS && err != -EFAULT) > c->status = Disconnected; > goto recalc_sigpending; > } > > c->trans_mod->request() calls p9_fd_request() in net/9p/trans_fd.c > which basically does a p9_fd_poll(). Again, I know nothing about 9p... but if p9_fd_request() returns an err < 0, then it comes from p9_conn->err and p9_fd_request() does nothing else. > Previously, the above would fail with err as -EIO which would > cause the client to "Disconnect" and the retry logic would make > progress. Now however, the err returned is -ERESTARTSYS OK... So p9_conn->err = -ERESTARTSYS was set by p9_conn_cancel() called by p9_write_work() because pipe_write() returns ERESTARTSYS? But I don't understand -EIO with the reverted commit aaec5a95d59615 Oleg.