From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0AA40275869; Mon, 18 Aug 2025 21:55:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755554140; cv=none; b=ffFX0zTauiJ18iGG6rWpqQF16PXfA3nwyDOcm+2jX1MY2a3DZ2piuYTMz+HU+OQUiUfTWhqqpHAnhyN3n66xvi663mzikydzLBx+BgoKBF5nnW8LP1R7yNDMr6DTVHebhzqe80rrPK/AkOZ7YxpLGxeVhOpMX8yi/AWBppacTmo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755554140; c=relaxed/simple; bh=AvPnhp8uiVkXXK54PS71qwBLejCBhN5BMJOLT95GAbM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CWmq7cmqPP1x+0LVdRLJg64nDF3Pk9sbd2/HUiw68zSOSxGK4RripO09RaPDHDqrBaW09yh/ife9su8Rwly/Wb2BOeJ5Gw4PvwCEV1WgwvAEMmU+uDL5ud9lBmdJviBB85+b8bqV958evRz3XSIEzB//SQVrjXlkiey5iFhdlpY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=moSNTz60; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="moSNTz60" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id C157514C2D3; Mon, 18 Aug 2025 23:55:30 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1755554135; 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=auLOhWoJLzMo5J4E2hQaw+rrZVFMM1bMgBRMGY/PL2o=; b=moSNTz60+w3p/T7Zd9IShd1kdgP0RV90fFSfnL1+vsHRSeh7tj/xyJii/z3OkUe+FH5nC6 nDIO9qHEMECFFjhGZMOLkqH8yUAM0Ai8uTeYNHFA90EYfsqxqbzBhPJ+TK7a9bv0eiGMuP 81V/4OSzpxsKhGaX+yZzdQ9VeD8rJB4c17ywfQUb2sLa7sGbm6H1iJ4i7zTPzIdcG0EAD6 q6aVhSJDZeodIqNpr0c6vxMg/IC8+57UCNk1ybDfE1powYj1yG2Q1Dxrf1CCkgRkQCX7YC emBsonRLxlE+KQdqi/00x1h+EfKsFJb+q1hvEaIK9T0W8yoWtDdh2iA66ixJYw== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id 05349875; Mon, 18 Aug 2025 21:55:29 +0000 (UTC) Date: Tue, 19 Aug 2025 06:55:13 +0900 From: Dominique Martinet To: Oleg Nesterov Cc: syzbot , David Howells , K Prateek Nayak , akpm@linux-foundation.org, brauner@kernel.org, dvyukov@google.com, elver@google.com, glider@google.com, jack@suse.cz, kasan-dev@googlegroups.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, willy@infradead.org Subject: Re: [syzbot] [fs?] [mm?] INFO: task hung in v9fs_file_fsync Message-ID: References: <20250818114404.GA18626@redhat.com> <68a31e33.050a0220.e29e5.00a6.GAE@google.com> <20250818125625.GC18626@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250818125625.GC18626@redhat.com> Hi Oleg, Oleg Nesterov wrote on Mon, Aug 18, 2025 at 02:56:26PM +0200: > On 08/18, syzbot wrote: > > syzbot has tested the proposed patch and the reproducer did not trigger any issue: (I hate that syzbot identified "hung in v9fs_file_fsync" but doesn't bother to Cc 9p folks... all the time..) > Dominique, David, > > Perhaps you can reconsider the fix that Prateek and I tried to propose > in this thread > > [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter > https://lore.kernel.org/all/67dedd2f.050a0220.31a16b.003f.GAE@google.com/ I've re-read that thread, and I still think this must be a problem specific to syzbot doing obviously bogus things (e.g. replying before request, or whatever it is this particular repro is doing), but I guess your patch is also sane enough and the 9p optimization is probably not really needed here Please resend as a proper patch, and I'll just run some quick check (and a trivial benchmark) and pick it up Thanks, -- Dominique Martinet | Asmadeus