From nobody Sun Mar 06 15:43:47 2022 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 2FA9E1A0EEF4; Sun, 6 Mar 2022 15:43:48 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4KBQqS0qQnz3qsY; Sun, 6 Mar 2022 15:43:48 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1646581428; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=kP+nKb9H0I0PAFZMad5F5gg4tUsYRVwwRnV+Z1KM99c=; b=dgpCzUABv7E/kpTi20vdJnJu46M78BnuT7ZcaB1wuVDmBiQaa8GXUlwHU/oY37hVYYDIeB 9rwkWk9ENcMto3gjFkKFfg1Y83CpjbwgH6ELsdRp4rYFkZmc/NDU6qcwB/n9DddT0S1sCa YNEmpBk3Khs4s1kfLV+aKqVDzynWExRwtRUhUZI7+ZfjocYg/YUB76bw9CYgUoyXZYl/cD E8Qt4oiJJped+U+a3TfIrOuAnsz7yAR0tC8YfGY932q+ivUq5KbcM69GZ8aiZcDQnKajOp dtOR0jTSYbWk9niS0bywjTYzMU6OUshoWimKP7V6JhE8oaTvYLSAV/iDVgjfAw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id F20A417386; Sun, 6 Mar 2022 15:43:47 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 226Fhll6011470; Sun, 6 Mar 2022 15:43:47 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 226FhlYu011469; Sun, 6 Mar 2022 15:43:47 GMT (envelope-from git) Date: Sun, 6 Mar 2022 15:43:47 GMT Message-Id: <202203061543.226FhlYu011469@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: 1fb00c8f1060 - main - buf_alloc(): Stop using LK_NOWAIT, use LK_NOWITNESS List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-main@freebsd.org X-BeenThere: dev-commits-src-main@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 1fb00c8f1060e18fed621f13d31db7b336d2267e Auto-Submitted: auto-generated ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1646581428; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=kP+nKb9H0I0PAFZMad5F5gg4tUsYRVwwRnV+Z1KM99c=; b=S3SwOTgPc7pXD4sGpEWNROCafGXuLBnQZ2dZBXArnbH1SRJw5o/ccr3dzsSD34/H3x0VxX NmE/YHPcCq0Ib4XR9E4AItYUHalg9NYLWdQlnisgbi9VQLcrDb4aI2bXenBMA0OQjMPG/l ZDtciHo7EopYcnVlXMmINnORJtuGMf8rf1pYbWRwGZrNTh7Aj4yN/5+ZHPEwnDWaRw2x6l VTl+yOO/7D1r0HTIn3Cenq0wNA3AfKwZWoutkuQ7j99uB+ub5v4GDiRZpUIKeAzb7gTzQT i/A7V5pOT/Js+J2ay9tn1bpY2WgoD8Cn5kYgyX0kBiggfTrU2fg31F68jRclGw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1646581428; a=rsa-sha256; cv=none; b=ddffx6xY67TrzI38/kVXoEVhb1ajdMUXjWsvCgr+kJW0zOtjMyMz0OPd5JAhzkWWk5AGFY z8E4qGte7Cc1OgV4nEkYxWGlJv3cbk3Zu3iN9c49b7dLLFYiIbaSGhWcssnKpndGaI9/0z MTOdIzqqW5D6sjM0uD0agtvEqj+2EQ16PZrBlUF3RaXHp7eklWIsKfvN1CrbFppaZK6/f7 1eYb6Z13TW3avEV0K/eyvf9vUjbjiTJBknil7qwP534XDMM/4hZPgeFNNxohRtFwvOzHQv er2sJmBe5IaAvKUbn3TbyP94Th6M4FxcQUj0y3juGZVQuQJfl5VjzvUO2o6m2A== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=1fb00c8f1060e18fed621f13d31db7b336d2267e commit 1fb00c8f1060e18fed621f13d31db7b336d2267e Author: Konstantin Belousov AuthorDate: 2022-02-16 15:30:17 +0000 Commit: Mark Johnston CommitDate: 2022-03-06 15:29:31 +0000 buf_alloc(): Stop using LK_NOWAIT, use LK_NOWITNESS Despite the buffer taken from cache or free list, it still can be locked, due to 'lockless lookup' in getblkx() potentially operating on the freed buffers. The lock is transient, but prevents the use of LK_NOWAIT there for the goal of neutralizing WITNESS. Just use LK_NOWITNESS. Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 3 days --- sys/kern/vfs_bio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 5c42f00809b8..9082147b6034 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -1722,7 +1722,7 @@ buf_alloc(struct bufdomain *bd) if (freebufs == bd->bd_lofreebuffers) bufspace_daemon_wakeup(bd); - error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); + error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, error)); (void)error;