From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831152; b=HbMyWhFrhY1Ix5PLcj9Fyu3Aj/BqaILzeG7ZA9Xf/fe6ZVv3tc0VoG5j+y1HMSbwjorl EeiAZeioPLS3OxrydiDDKxVf6pnDTbWofOj43EZ6aBOsrXpQMrlm6yOwnYqtz1oNYOXgd 7LM0FpP4MeszQOjCnREt2tf9bGauc57jWcYk34d60VY3Xvv2q2A/A5s1VnzaFqQHl977d hUGwoIjdRs9gMP3GqyL4r/hDEC7K6j/dDrMOy8XyyzTV8ODKoal6w3t8GypaRFopKl3XU sKfe6dm/fYYic6cEixolVHu5+7QydP8OSSdStm9MM9g2vmy/06vwucMtOjgetQd6ZGw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831152; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=L4zIdph3jfMWCj+XRagElgq3oTEI4nQmYaL8fmzbp/o=; b=Eak0sDlbBYNp1Lp1owhmEBP6cXQuWQMdq3kgpR7K6w9poryCM36Owjcb/XU2cXIx7nTd tkkCQ6Zk8SkX/H6vwksVnAIhqUlh73GpCeYGBoUQGKmZTOTSbojWIo7CvEp20x07ZxYOc H5fPWpvwdKL7PFZzGIP7eboYzk3oreYcq1wSIIWF0uy9G6tCGB/FwX3E0hzBGGlzDV+ib Q0kOxOr7neCnua8ZRw7ihV9ZH2kmCGa2JP4P5l2hLuHPX/i/GsScdnOGtIbFP1DLthYwS yMLzB4SaeG9m2yIUuhNkd35Xo7yrVmWJjzRCQaw8J+tIefyL4V132CgwG1VsRag5tVA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=lAKKHVAU; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3505C606D81A; Wed, 4 Nov 2026 22:25:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=lAKKHVAU Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAE631F00919; Wed, 4 Nov 2026 22:25:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831152; bh=L4zIdph3jfMWCj+XRagElgq3oTEI4nQmYaL8fmzbp/o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lAKKHVAUf0Hea+hgYvlxQyYTAqhiTXfP5cH+wEKjA/gZULFldBEKfCfNcOgTFrxZE Ne4EIopMNbfftteuY3GeAL5k4YXztmosSdDMjRv2XqmnDcLVVVtLlcdFM8nViWUil9 hmLgMoaI0ZB6vsr4vLaXYWhrAy6kmGPogwAzS3Nk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cen Zhang , Andrew Morton , Joseph Qi , Mark Fasheh , Joel Becker , Heming Zhao , Jia-Ju Bai , jjzuming@gmail.com Subject: [PATCH 6.18 0529/1005] ocfs2/dlm: drain join handlers before releasing module text Date: Wed, 4 Nov 2026 16:04:22 -0500 Message-ID: <20261104211058.729663297@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang commit 28f366d84023651e50e32e29931401ba0df3e679 upstream. The code for a registered DLM handler must remain resident until its last invocation finishes. dlm_unregister_net_handlers() only removes dlm_join_handlers from the o2net registry. o2net_handler_get() takes a kref on the wrapper, but that reference does not pin ocfs2_dlm text. o2net_process_message() calls nh_func after dropping o2net_handler_lock. With CONFIG_OCFS2_FS_O2CB=m, ocfs2_dlm can be loaded independently of ocfs2_stack_o2cb while nodemanager continues handling messages from a configured, heartbeating peer. If no dependent module or module reference prevents normal unload, the following ordering is possible: Receive worker Module unload -------------- ------------- o2net_handler_get() take wrapper kref drop handler lock dlm_exit() unregister handlers release DLM module text call saved nh_func in released module text Use o2net_unregister_and_flush_handler_list() in the shared DLM unregister helper. It first prevents new lookups, then waits for the ordered o2net workqueue to drain, including a concurrent destruction of that queue. The acquired invocation therefore finishes before dlm_exit() returns and the loader releases the callback code. The same helper covers partial registration and dlm_init() error unwind before module memory is released. Skip the drain when the private join-handler list is empty. Early dlm_init() failures can reach this helper before any handler has been published. Partial-registration failure also reaches it a second time after the first call has already unregistered and drained the list. Neither case needs to take o2net_wq_mutex or drain unrelated work. The list is changed only by serialized module init/exit paths; a nonempty list still uses the full unregister-and-flush helper. Oops report as below: Oops: int3: 0000 [#1] SMP KASAN NOPTI CPU: 2 UID: 0 PID: 54 Comm: kworker/u16:3 Not tainted 7.3.0-rc4-next-20260921-pmb-ocfs2-functional-v1+ #1 PREEMPT(lazy) Hardware identification omitted. Workqueue: o2net o2net_rx_until_empty [ocfs2_nodemanager] RIP: 0010:0xffffffffc0423871 [Instruction byte dump omitted.] Register dump omitted. Call Trace: ? o2net_rx_until_empty+0x19b1/0x3300 [ocfs2_nodemanager] ? __pfx_o2net_rx_until_empty+0x10/0x10 [ocfs2_nodemanager] ? lock_acquire+0x190/0x300 ? process_one_work+0x935/0x1b40 ? process_one_work+0x834/0x1b40 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_release+0xc8/0x290 ? srso_alias_return_thunk+0x5/0xfbef5 ? process_one_work+0x9a8/0x1b40 ? __pfx_process_one_work+0x10/0x10 ? lock_acquire+0x190/0x300 ? lock_is_held_type+0x8f/0x100 ? srso_alias_return_thunk+0x5/0xfbef5 ? worker_thread+0x65c/0xe40 ? srso_alias_return_thunk+0x5/0xfbef5 ? __kthread_parkme+0x177/0x220 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_worker_thread+0x10/0x10 ? kthread+0x351/0x460 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_kthread+0x10/0x10 ? ret_from_fork+0x659/0x940 ? __pfx_ret_from_fork+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __switch_to+0x74f/0xf70 ? __pfx_kthread+0x10/0x10 ? ret_from_fork_asm+0x1a/0x30 Modules linked in: ocfs2_nodemanager [last unloaded: ocfs2_dlm] ---[ end trace 0000000000000000 ]--- Link: https://lore.kernel.org/pm-ocfs2-objects-candidate-0076-v6-12de5f4628f57fba3be3@gmail.com Fixes: 6714d8e86bf4 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem") Signed-off-by: Cen Zhang Signed-off-by: Andrew Morton Reviewed-by: Joseph Qi Assisted-by: LLM Cc: Mark Fasheh Cc: Joel Becker Cc: Heming Zhao Cc: Jia-Ju Bai Cc: Cc: Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/dlm/dlmdomain.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/ocfs2/dlm/dlmdomain.c +++ b/fs/ocfs2/dlm/dlmdomain.c @@ -2213,7 +2213,8 @@ static LIST_HEAD(dlm_join_handlers); static void dlm_unregister_net_handlers(void) { - o2net_unregister_handler_list(&dlm_join_handlers); + if (!list_empty(&dlm_join_handlers)) + o2net_unregister_and_flush_handler_list(&dlm_join_handlers); } static int dlm_register_net_handlers(void)