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[209.132.180.67]) by mx.google.com with ESMTP id c66si4752782pga.494.2018.04.13.14.17.52; Fri, 13 Apr 2018 14:18:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=c+Hh9Hit; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751892AbeDMVPe (ORCPT + 99 others); Fri, 13 Apr 2018 17:15:34 -0400 Received: from mail-pf0-f179.google.com ([209.85.192.179]:47090 "EHLO mail-pf0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbeDMVPc (ORCPT ); Fri, 13 Apr 2018 17:15:32 -0400 Received: by mail-pf0-f179.google.com with SMTP id h69so6859483pfe.13 for ; Fri, 13 Apr 2018 14:15:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=pRdOGpv8T2UVE/qVkeqEfmrtEWE3sFcC57YbeL/9V9k=; b=c+Hh9HitKKcTnQwJ8xuSo0jFphnoKCW0LNOCfSLKQmgOwskQ2KSpYweuHfkucnvwly eGgsKaxrR28EdyplJXTef+aKcGv/lin9w57UdAjRueh8L6zZ9IZUh/jVoGlhI6qGC6U6 oJb5oLtouuyZRwnUWI1DOYvUPoyMMLi80o6qUBMixdlprp+8p2g11CF1Ofb+ANH6bdxU bmg/6AKfMl/uXo4RaJ9m3cMCtfYIXFkcF3AQpd9P8gRXMXM4Jp3BaJT1wTfbnERALZVd xYnTz/lpA4RhTKRTMBfBZLEf6BTa6t2dBMDcLtuvUmxyCr7uOGqp1sRgdRZvgOEpY3Ie PoPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=pRdOGpv8T2UVE/qVkeqEfmrtEWE3sFcC57YbeL/9V9k=; b=o12lUZVkIVFHs66lNYnVFprWmPGV6lXonUuZ8NV01JapbrYTWzC+TZbuvRT+k6zsZJ T6Ln5d+z9jf+zB9xLTk1mD9IvmrGiGfWy2rAfXthkr54YpSXna3XJFx3RhDR/ATjwbQN l8GAN5gioHp7Bjk14SDzT/oYy47fao1j4Dk48ZDt2X5fON/ymI1ADEUsc2krt567gv6I FNz+gze9H8LnkbCU66QLIauUTU/nIKLhxiOlE7Go3lTeZD9I7O/cPhO2T+NGoGmtoOlm Dv8IyXxK5eNgfbr4pcKU0d5J7G9bsY73x1+Ui+xxrDgSloi7laWc3FbraDyZ79kEsI4f zxwA== X-Gm-Message-State: ALQs6tDUMn42aXjLJNZzRHH/eLdJVFrTjA1z19d8KnEQHoPFGiHE9iDQ JOLkZ2XvD8AmDDN5hk1I2NU2dg== X-Received: by 10.98.55.69 with SMTP id e66mr5018358pfa.253.1523654131624; Fri, 13 Apr 2018 14:15:31 -0700 (PDT) Received: from [2620:15c:17:3:3a5:23a7:5e32:4598] ([2620:15c:17:3:3a5:23a7:5e32:4598]) by smtp.gmail.com with ESMTPSA id u4sm12220917pfh.120.2018.04.13.14.15.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 13 Apr 2018 14:15:31 -0700 (PDT) Date: Fri, 13 Apr 2018 14:15:30 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Khazhismel Kumykov cc: nborisov@suse.com, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Goldwyn Rodrigues , Jeff Mahoney , Davidlohr Bueso , Linus Torvalds Subject: Re: [PATCH] fs/dcache.c: re-add cond_resched() in shrink_dcache_parent() In-Reply-To: <20180413202823.204377-1-khazhy@google.com> Message-ID: References: <20180413181350.88831-1-khazhy@google.com> <20180413202823.204377-1-khazhy@google.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 13 Apr 2018, Khazhismel Kumykov wrote: > shrink_dcache_parent may spin waiting for a parallel shrink_dentry_list. > In this case we may have 0 dentries to dispose, so we will never > schedule out while waiting for the parallel shrink_dentry_list to > complete. > > Tested that this fixes syzbot reports of stalls in shrink_dcache_parent() > > Fixes: 32785c0539b7 ("fs/dcache.c: add cond_resched() in shrink_dentry_list()") > Reported-by: syzbot+ae80b790eb412884ca77@syzkaller.appspotmail.com > > Cc: Nikolay Borisov > Cc: Andrew Morton > Cc: David Rientjes > Cc: Alexander Viro > Cc: Goldwyn Rodrigues > Cc: Jeff Mahoney > Cc: Davidlohr Bueso > Cc: Linus Torvalds > Signed-off-by: Khazhismel Kumykov Acked-by: David Rientjes