From nobody Sat Apr 25 19:58:09 2026 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 4g30xZ24wbz6NTWK for ; Sat, 25 Apr 2026 19:58:10 +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 "R13" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4g30xY6Smlz3lc5 for ; Sat, 25 Apr 2026 19:58:09 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1777147089; 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=9QnYG78QIDk2wb5r+IfHdfZ8Px1Bbnvoq3Bb09tgGQY=; b=hUKh9EhJGcJ/4CKb5XDmh7Q+NRsRaKaw8gJK3zr2EWLRLitWnpTtAr6W2Rkf9aHk85qqPb EUTRzX5NsYkEV2pQV8PLJt8/XJ5a3qdW8dUbNrrB47M8bc0mlK3it+U0rqGoI05O2Cfbn5 /agIVfc0CJ6+Yirx1PuwYI1PeMR2l9k8P2Itcgk+3E0wLi3GXDr3xALOdiSBKghLFMPZjB Uly9zTFvV59ePMlDx+RtCi47wBAm+cXpXaU26Bbqk0ai5AkL7BI3AryfFRzwj3m1UFehCk G18J3QKxpaUQ+IlrF6ddO3xPh2acno2OO3SNe4oqpVnuIgCXywF4FJvb1HJDJA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1777147089; a=rsa-sha256; cv=none; b=t7q10XXV5jSZ9DuPinZqwuiiawaEL/KUgtKUXUlvuzr6lx0d8mpWJBkP4YFgEmdoJMiyBw l2TxTSVv+SkwAUD5YyfHXTRFcf/RPvZRMvEV+WeHTVTCVYE/zMknltjyt/iolKNGFY2+Wn Xl5QioZJ9Ph8d+1auKYciKPcBBBeUuizuaw5Pe2zWZxta3bPULexvl7s8yoDZ9JV3P91JI W3kgEyE5NoPpE09JbegUOAel69Iujf49kLpsoaS4hMQlxsXc0MxjpMIQ5eHNKEYzJfm1tJ 7Q0CzV7/fcLHe6XKEZGrMwM37/q48bW6oklhGP1ynr74q2rJDwDtJwewVdbG2A== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1777147089; 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=9QnYG78QIDk2wb5r+IfHdfZ8Px1Bbnvoq3Bb09tgGQY=; b=vYWA/vsDb8IsQCk4Iko0NupNPN6RKAKAUM+QUkGk8UXmqj4bUlfxkb6UXE/2jE9nTxDIK5 kIULKDhJs18fCmmHpuKMELxYbkwoP7FkzLQbD7RjChChFyei1hEaUscLrd1+ZYmA+JXERF ghlhNGUvoLzG29m3Ay7FyJxjWMOL1+AeXfuW2dbievAsK40EYeo540Y6GdJFxQP1zKtcq7 wbE91iKLO0EUtAWZCfUmX3QA4Zhl0vH+9JWfr3WhNEmrm1zK19cQD/fskUZDfXKEteL93Q dmhVust5v5cMvg+VJECySHoEri0+5BgFrb+FXC0INbGtelkSo0XJUl1Vg96yfA== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4g30xY5pMLzpVT for ; Sat, 25 Apr 2026 19:58:09 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 321ce by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Sat, 25 Apr 2026 19:58:09 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Zhenlei Huang Subject: git: ba7f47d47dc1 - main - ifnet: if_detach(): Fix races with vmove operations 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: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: zlei X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: ba7f47d47dc1a177e4d8f115f791ec25f3da0eab Auto-Submitted: auto-generated Date: Sat, 25 Apr 2026 19:58:09 +0000 Message-Id: <69ed1cd1.321ce.9cf70d7@gitrepo.freebsd.org> The branch main has been updated by zlei: URL: https://cgit.FreeBSD.org/src/commit/?id=ba7f47d47dc1a177e4d8f115f791ec25f3da0eab commit ba7f47d47dc1a177e4d8f115f791ec25f3da0eab Author: Zhenlei Huang AuthorDate: 2026-04-25 19:56:07 +0000 Commit: Zhenlei Huang CommitDate: 2026-04-25 19:56:07 +0000 ifnet: if_detach(): Fix races with vmove operations The rationality is that the driver private data holds a strong reference to the interface, and the detach operation shall never fail. Given the vmove operation, if_vmove_loan(), if_vmove_reclaim() or vnet_if_return() is not atomic and spans multiple steps, acquire ifnet_detach_sxlock only for if_detach_internal() and if_vmove() is not sufficient. It is possible that the thread running if_detach() sees stale vnet, or the vmoving is in progress, then if_unlink_ifnet() will fail. Fix that by extending coverage of ifnet_detach_sxlock a bit to also cover if_unlink_ifnet(), so that the entire detach and vmove operation is serialized. Given it is an error when the if_unlink_ifnet() fails, and if_detach() is a public KPI, prefer panic() over assertion on failure, to indicate explicitly that bad thing happens. That shall also prevent potential corrupted status of the interface, which is a bit hard to diagnose. PR: 292993 Reviewed by: glebius MFC after: 5 days Differential Revision: https://reviews.freebsd.org/D56374 --- sys/net/if.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/sys/net/if.c b/sys/net/if.c index 8a148ba0fd06..e421dd3bd494 100644 --- a/sys/net/if.c +++ b/sys/net/if.c @@ -447,6 +447,7 @@ if_unlink_ifnet(struct ifnet *ifp, bool vmove) struct ifnet *iter; int found = 0; + sx_assert(&ifnet_detach_sxlock, SX_XLOCKED); IFNET_WLOCK(); CK_STAILQ_FOREACH(iter, &V_ifnet, if_link) if (iter == ifp) { @@ -1028,14 +1029,23 @@ if_detach(struct ifnet *ifp) { bool found; + /* + * The driver private data holds a strong reference to the ifnet, and + * it is actually the "owner", hence this routine shall never fail. + * + * Ideally we can loop retrying when we lose race with other threads + * those run if_unlink_ifnet(). For simplicity, use ifnet_detach_sxlock + * to serialize all the detach / vmove operations. + */ + sx_xlock(&ifnet_detach_sxlock); CURVNET_SET_QUIET(ifp->if_vnet); found = if_unlink_ifnet(ifp, false); - if (found) { - sx_xlock(&ifnet_detach_sxlock); - if_detach_internal(ifp, false); - sx_xunlock(&ifnet_detach_sxlock); - } + if (! found) + panic("%s: interface is not on the active list", + ifp->if_xname); + if_detach_internal(ifp, false); CURVNET_RESTORE(); + sx_xunlock(&ifnet_detach_sxlock); } /* @@ -1290,13 +1300,14 @@ if_vmove_reclaim(struct thread *td, char *ifname, int jid) } /* Get interface back from child jail/vnet. */ + sx_xlock(&ifnet_detach_sxlock); found = if_unlink_ifnet(ifp, true); if (! found) { + sx_xunlock(&ifnet_detach_sxlock); CURVNET_RESTORE(); prison_free(pr); return (ENODEV); } - sx_xlock(&ifnet_detach_sxlock); if_vmove(ifp, vnet_dst); sx_xunlock(&ifnet_detach_sxlock); CURVNET_RESTORE();