From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 89D71CA40; Tue, 16 Jul 2024 15:36:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721144192; cv=none; b=miYjX97IUjzjzLUN4AqB9gdlKsvDP2zhnk2llmAGgQs27hiuHw15vBzCCI1LCo3AuUVKa4Rvi9hY6XVVWIGwciUmbRL1j6Gi9XMd/w+al1fWLJPO4Y3QNQ9TGurDLtKJK8dbAdRw+Js41CiYH3Pmz7b/nJeOUQnaGQVEJs7f1bI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721144192; c=relaxed/simple; bh=UpTmUxMEfSm21Xh64MtpgM3EDnLpQwaRiBEOl3QQYGY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NcVUJczVmSojSIvSU2TRTqnC2AbsbBbww4+0uCWdivi2pZrq2PpGfsSvupd3NdeYdGzjxihaQ8a55mXzgrQE1QsLZbRANUCiZoJSr/B8FkM6Y0xgKD082oId8bNADHyq3Z7zodeFTGshEsKP6hKYB//lQxtxoYvDCL2b0fUbMgM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GxwCprZc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GxwCprZc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1250EC116B1; Tue, 16 Jul 2024 15:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1721144192; bh=UpTmUxMEfSm21Xh64MtpgM3EDnLpQwaRiBEOl3QQYGY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GxwCprZc8W/Oli8jXrVrCY1eeoVgP1c5JJw5ZHDyKgXYVA0kNrlrRizNiygUmKqbh St/+SqmuR7oYEu7/xPqrkCXNWBl79m3H17tCyMWU453CTG8s+d+vJboGdSsV2mlwiw 7DlbizayFkrakqAXHPNnuAb+pQRgfZR3E0qMB5BY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ilya Dryomov , Xiubo Li Subject: [PATCH 4.19 59/66] libceph: fix race between delayed_work() and ceph_monc_stop() Date: Tue, 16 Jul 2024 17:31:34 +0200 Message-ID: <20240716152740.413405471@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240716152738.161055634@linuxfoundation.org> References: <20240716152738.161055634@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ilya Dryomov commit 69c7b2fe4c9cc1d3b1186d1c5606627ecf0de883 upstream. The way the delayed work is handled in ceph_monc_stop() is prone to races with mon_fault() and possibly also finish_hunting(). Both of these can requeue the delayed work which wouldn't be canceled by any of the following code in case that happens after cancel_delayed_work_sync() runs -- __close_session() doesn't mess with the delayed work in order to avoid interfering with the hunting interval logic. This part was missed in commit b5d91704f53e ("libceph: behave in mon_fault() if cur_mon < 0") and use-after-free can still ensue on monc and objects that hang off of it, with monc->auth and monc->monmap being particularly susceptible to quickly being reused. To fix this: - clear monc->cur_mon and monc->hunting as part of closing the session in ceph_monc_stop() - bail from delayed_work() if monc->cur_mon is cleared, similar to how it's done in mon_fault() and finish_hunting() (based on monc->hunting) - call cancel_delayed_work_sync() after the session is closed Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/66857 Signed-off-by: Ilya Dryomov Reviewed-by: Xiubo Li Signed-off-by: Greg Kroah-Hartman --- net/ceph/mon_client.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/net/ceph/mon_client.c +++ b/net/ceph/mon_client.c @@ -963,13 +963,19 @@ static void delayed_work(struct work_str struct ceph_mon_client *monc = container_of(work, struct ceph_mon_client, delayed_work.work); - dout("monc delayed_work\n"); mutex_lock(&monc->mutex); + dout("%s mon%d\n", __func__, monc->cur_mon); + if (monc->cur_mon < 0) { + goto out; + } + if (monc->hunting) { dout("%s continuing hunt\n", __func__); reopen_session(monc); } else { int is_auth = ceph_auth_is_authenticated(monc->auth); + + dout("%s is_authed %d\n", __func__, is_auth); if (ceph_con_keepalive_expired(&monc->con, CEPH_MONC_PING_TIMEOUT)) { dout("monc keepalive timeout\n"); @@ -994,6 +1000,8 @@ static void delayed_work(struct work_str } } __schedule_delayed(monc); + +out: mutex_unlock(&monc->mutex); } @@ -1106,13 +1114,15 @@ EXPORT_SYMBOL(ceph_monc_init); void ceph_monc_stop(struct ceph_mon_client *monc) { dout("stop\n"); - cancel_delayed_work_sync(&monc->delayed_work); mutex_lock(&monc->mutex); __close_session(monc); + monc->hunting = false; monc->cur_mon = -1; mutex_unlock(&monc->mutex); + cancel_delayed_work_sync(&monc->delayed_work); + /* * flush msgr queue before we destroy ourselves to ensure that: * - any work that references our embedded con is finished.