From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751208AbeDMU24 (ORCPT ); Fri, 13 Apr 2018 16:28:56 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:33915 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750839AbeDMU2y (ORCPT ); Fri, 13 Apr 2018 16:28:54 -0400 X-Google-Smtp-Source: AIpwx48qPBI2oD5nqPm4MBVHZ/27cy/VQvnr7vZp+fceTYqoVENN6ocAV7/7T50bqZ7xpM3SZwz9+g== From: Khazhismel Kumykov To: nborisov@suse.com, akpm@linux-foundation.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Khazhismel Kumykov , David Rientjes , Alexander Viro , Goldwyn Rodrigues , Jeff Mahoney , Davidlohr Bueso , Linus Torvalds Subject: [PATCH] fs/dcache.c: re-add cond_resched() in shrink_dcache_parent() Date: Fri, 13 Apr 2018 13:28:23 -0700 Message-Id: <20180413202823.204377-1-khazhy@google.com> X-Mailer: git-send-email 2.17.0.484.g0c8726318c-goog In-Reply-To: <20180413181350.88831-1-khazhy@google.com> References: <20180413181350.88831-1-khazhy@google.com> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="f403045dbf568b74990569c0b84a" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --f403045dbf568b74990569c0b84a 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 --- fs/dcache.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/dcache.c b/fs/dcache.c index 591b34500e41..3507badeb60a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1489,6 +1489,7 @@ void shrink_dcache_parent(struct dentry *parent) break; shrink_dentry_list(&data.dispose); + cond_resched(); } } EXPORT_SYMBOL(shrink_dcache_parent); -- 2.17.0.484.g0c8726318c-goog --f403045dbf568b74990569c0b84a Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic 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