From nobody Sat Jul 8 19:07:31 2023 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 4Qz0Bq55J5z4m6lk; Sat, 8 Jul 2023 19:07:31 +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 4Qz0Bq4J6Bz3CWf; Sat, 8 Jul 2023 19:07:31 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1688843251; 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=TvBA/HgZv4OiDm5m9VeB+lydDSmivsYaXeIotemJQek=; b=k66Hpz12UdR+7Mf7JcPwxfUgVdVhvlepWm6evuBpDirspvtAqYbn8i5gL18TWSVw/J8MfC 0T/uOXLKNklhl9jA3/hTWQ5fA13zmzhhM8Hb8p3IdPeRSO+t/Ayk/rwEfqBoQuNVWoUSsE 4JgCwyRwtVF0KNQipEUboPmNZ5QbcHXUbBDj+tS9kfxr4MNgS83acjktNut4ALYHmoURfY jNfRGFslatL3gwvqNG+bGWW0qr+JwdLgjmoZpsWpBhefXqUQD8xV9BUXCU8Ld/Tnd1apqP Lbelqpd1MPIxXQ0KLKzVnUBsO+S/mtWX+Wlg5DYcc7eGfgI1VhhLf4z14RdW3Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1688843251; 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=TvBA/HgZv4OiDm5m9VeB+lydDSmivsYaXeIotemJQek=; b=GlMZ5bKy/ULfP2I+0SBZXNXagn/6xvcHj4/5W1hWrl8ZdrAXV6s93JA/3zD913NLisxNb0 uuIwCELgm7vz+ktvZ8f7I8gw2qDg8w/Z2ooX65lHb4mLddoycajJKpu6lTRtQEct+4qaFz Oe/iH+WSk3My3Iw0GHuBsJFBBB8q40jiuIIqcO4jbXwKn7Xr7038EYgmGTRJ9lYAMGaKsG vLmVI60aa2XyK1ALCH7p1l2K+V6oS1qPNYzM7g8TFT6z+Sc00l3JnT31uqs/9iqMIUp6sV ewIhUZ7RCyFhhbmku3psCgrc6rQJMOEnuC/Kohb4Rt5njujBfF61x8CyiSC/hw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1688843251; a=rsa-sha256; cv=none; b=FUY2aKRQdDt2Yce92JRmBTxvvbnmBE1iKb0Gds8XZlzfVBdX8qgkBNOHAkKlyPk5kk93Gn eLUUjy3J4/qHLiralL0bt8WBWd7eXHbTkEwO/WSPrDzdCgUJIns0A6bJnaAXzG90STxjV6 BRwxvLITMqTU8S6bi268Jxr/nd+Pewb7ekm64sO58L5vi9zulzZzkq7Haa7enSseCI9wP/ trv+5AKPJsi7DyVEfei+QRpXy68dbkG76o94FXL0Am8MbGp49V/QDxY8Hsn3RtKiO9BFZq zQg1xeZvXhyiBwuYYZwc6z5R+YEVFcqMlDge4cKXxpViPsRK83OhBo9LaJpr0w== 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 4Qz0Bq3N4hzXhB; Sat, 8 Jul 2023 19:07:31 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.17.1/8.17.1) with ESMTP id 368J7VrE011286; Sat, 8 Jul 2023 19:07:31 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.17.1/8.17.1/Submit) id 368J7VLL011285; Sat, 8 Jul 2023 19:07:31 GMT (envelope-from git) Date: Sat, 8 Jul 2023 19:07:31 GMT Message-Id: <202307081907.368J7VLL011285@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Konstantin Belousov Subject: git: 7a70f17ac4bd - main - killpg(): more carefully avoid LoR 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: kib X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 7a70f17ac4bd64dc1a5020f963ba4380cf37b7e5 Auto-Submitted: auto-generated X-ThisMailContainsUnwantedMimeParts: N The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=7a70f17ac4bd64dc1a5020f963ba4380cf37b7e5 commit 7a70f17ac4bd64dc1a5020f963ba4380cf37b7e5 Author: Konstantin Belousov AuthorDate: 2023-07-07 17:19:33 +0000 Commit: Konstantin Belousov CommitDate: 2023-07-08 19:05:25 +0000 killpg(): more carefully avoid LoR otherwise we could end up with the livelock. When pg_killsx trylock failed, ensure that we do wait for lock availability before retry. Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week --- sys/kern/kern_proc.c | 15 +++++++++++++-- sys/kern/kern_prot.c | 6 ++---- 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c index 6d804d93eccc..b82dd07b17c1 100644 --- a/sys/kern/kern_proc.c +++ b/sys/kern/kern_proc.c @@ -587,8 +587,12 @@ enterpgrp(struct proc *p, pid_t pgid, struct pgrp *pgrp, struct session *sess) ("enterpgrp: session leader attempted setpgrp")); old_pgrp = p->p_pgrp; - if (!sx_try_xlock(&old_pgrp->pg_killsx)) + if (!sx_try_xlock(&old_pgrp->pg_killsx)) { + sx_xunlock(&proctree_lock); + sx_xlock(&old_pgrp->pg_killsx); + sx_xunlock(&old_pgrp->pg_killsx); return (ERESTART); + } MPASS(old_pgrp == p->p_pgrp); if (sess != NULL) { @@ -656,11 +660,18 @@ enterthispgrp(struct proc *p, struct pgrp *pgrp) ("%s: p %p belongs to pgrp %p", __func__, p, pgrp)); old_pgrp = p->p_pgrp; - if (!sx_try_xlock(&old_pgrp->pg_killsx)) + if (!sx_try_xlock(&old_pgrp->pg_killsx)) { + sx_xunlock(&proctree_lock); + sx_xlock(&old_pgrp->pg_killsx); + sx_xunlock(&old_pgrp->pg_killsx); return (ERESTART); + } MPASS(old_pgrp == p->p_pgrp); if (!sx_try_xlock(&pgrp->pg_killsx)) { sx_xunlock(&old_pgrp->pg_killsx); + sx_xunlock(&proctree_lock); + sx_xlock(&pgrp->pg_killsx); + sx_xunlock(&pgrp->pg_killsx); return (ERESTART); } diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c index 1fac6c496945..46d73a471291 100644 --- a/sys/kern/kern_prot.c +++ b/sys/kern/kern_prot.c @@ -347,10 +347,8 @@ again: error = EPERM; } else { error = enterpgrp(p, p->p_pid, newpgrp, newsess); - if (error == ERESTART) { - sx_xunlock(&proctree_lock); + if (error == ERESTART) goto again; - } MPASS(error == 0); td->td_retval[0] = p->p_pid; newpgrp = NULL; @@ -460,11 +458,11 @@ again: error = enterthispgrp(targp, pgrp); } done: - sx_xunlock(&proctree_lock); KASSERT(error == 0 || newpgrp != NULL, ("setpgid failed and newpgrp is NULL")); if (error == ERESTART) goto again; + sx_xunlock(&proctree_lock); uma_zfree(pgrp_zone, newpgrp); return (error); }