From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail115-100.sinamail.sina.com.cn (mail115-100.sinamail.sina.com.cn [218.30.115.100]) (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 DD54FDDA3 for ; Thu, 4 Apr 2024 02:13:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.30.115.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712196796; cv=none; b=leqE0TY4O5cSOOaIgw2Zbu8jH+cy/o53a9NApHPlyb9kkR2/2wCEtuOxbPiuIBxQoGaZYCK9jEDIo+8Iv4t/ZG8f5qha3QtPdxJ9luCrSom1wiLQLCSUswOJwu0CmGt0XumjeiaskJeShrM12XnUfWp4ZloZ3+CDuAE1eMw8rOs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712196796; c=relaxed/simple; bh=z7BkxFJVzxOf2S0RNFaj+RkUoL5NLhpfjuXiSbRfpcw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=QsjOp9q3XDWksr67rdkADhGGFUoR6pZWC6Ph8ew0Cwpo1xt7uTalzXrFv07Pk/m/XTVVaprWzLl2FY+huxc+ppJaEAHEHvVJNh0/+kfgcGYFvK1LeMmy/IxO2qGgnOzoqDy+wlVNnSwmembw2wQ+ajCvEnUpXR/LVidjWvDASQY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; arc=none smtp.client-ip=218.30.115.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([113.88.48.253]) by sina.com (172.16.235.24) with ESMTP id 660E0CB2000020DC; Thu, 4 Apr 2024 10:13:09 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 9655045089351 X-SMAIL-UIID: BCF4CD0B993E4605825F83FBC34E4B36-20240404-101309-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [kernfs?] possible deadlock in kernfs_fop_llseek Date: Thu, 4 Apr 2024 10:12:57 +0800 Message-Id: <20240404021257.4018-1-hdanton@sina.com> In-Reply-To: <00000000000098f75506153551a1@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 03 Apr 2024 11:23:26 -0700 > syzbot found the following issue on: > > HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel.. > git tree: upstream > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c38139180000 #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fe46a7dd189e --- x/fs/overlayfs/util.c +++ y/fs/overlayfs/util.c @@ -1159,9 +1159,8 @@ int ovl_nlink_start(struct dentry *dentr return err; } - err = ovl_inode_lock_interruptible(inode); - if (err) - return err; + if (!mutex_trylock(&OVL_I(inode)->lock)) + return -EBUSY; err = ovl_want_write(dentry); if (err) --