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 B6BF5194AD7; Mon, 23 Mar 2026 13:04:48 +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=1774271088; cv=none; b=uE6oxXzrK70m+vsuXmLGZQNFJBvfMQKG2Ig3D66tAK9bvBm9iH1Z53cUWkX7ZZhwM+PZgS6p/JXnNK4NdGuAZ0p3j00VtO2+Du46xjHCxGfdYNKPdHB78RbyzjknDM7iQ7Der1W8hgZwVEvnCJGCL/2hP43bFwg/1hMv25OQ5cU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774271088; c=relaxed/simple; bh=beMDJA3aNT3RHRUCvb+d9gBZnwCyhVvZxT6aFHZNjDs=; h=Subject:To:Cc:From:Date:In-Reply-To:Message-ID:MIME-Version: Content-Type; b=GgTaWPoZ/PZVK1C9tmTh9WkpkYEMACpUcrAoOJnV0PWjDGwgujKcSa6C0SJWbtDWRi4BJ/gotwdTKjUKWZb2DFcHL2tTmiVo3eAdjlnuY3b3lhWvjTxlrVjyvqOtlLgtrM9enag+ryrTU2AeO8JTC7HMnsE6v20+Ji9HYEvf0qM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AvHvCRAs; 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="AvHvCRAs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E134C4CEF7; Mon, 23 Mar 2026 13:04:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774271088; bh=beMDJA3aNT3RHRUCvb+d9gBZnwCyhVvZxT6aFHZNjDs=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=AvHvCRAsrhtPBY0rbZ79YCG+Q4C1kQe6+by7zg1m30/10sqa4THFx+tk7a2Apb/Th M1M4FcFcLwWu/mVMtiyvWlJlNfvgE3xaUxFm2189bkipOhR0ig1GOIiTQiduuPCo9U tkOXOlpUPxyjTzelOqe/tp5CBCJWRKaq975UCs2A= Subject: Patch "rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access" has been added to the 6.1-stable tree To: frederic@kernel.org,gregkh@linuxfoundation.org,jiangshanlai@gmail.com,jianqkang@sina.cn,joel@joelfernandes.org,josh@joshtriplett.org,mathieu.desnoyers@efficios.com,neeraj.upadhyay@kernel.org,patches@lists.linux.dev,paulmck@kernel.org,qiang.zhang1211@gmail.com,quic_neeraju@quicinc.com,rostedt@goodmis.org Cc: From: Date: Mon, 23 Mar 2026 14:03:51 +0100 In-Reply-To: <20260304024934.2364383-1-jianqkang@sina.cn> Message-ID: <2026032351-untidy-cyclic-2027@gregkh> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore This is a note to let you know that I've just added the patch titled rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rcu-nocb-fix-possible-invalid-rdp-s-nocb_cb_kthread-pointer-access.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From jianqkang@sina.cn Wed Mar 4 03:49:40 2026 From: Jianqiang kang Date: Wed, 4 Mar 2026 10:49:34 +0800 Subject: rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access To: gregkh@linuxfoundation.org, stable@vger.kernel.org, qiang.zhang1211@gmail.com Cc: patches@lists.linux.dev, linux-kernel@vger.kernel.org, paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, rcu@vger.kernel.org, neeraj.upadhyay@kernel.org Message-ID: <20260304024934.2364383-1-jianqkang@sina.cn> From: Zqiang [ Upstream commit 1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1 ] In the preparation stage of CPU online, if the corresponding the rdp's->nocb_cb_kthread does not exist, will be created, there is a situation where the rdp's rcuop kthreads creation fails, and then de-offload this CPU's rdp, does not assign this CPU's rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and rdp's->rdp_gp->nocb_gp_kthread is still valid. This will cause the subsequent re-offload operation of this offline CPU, which will pass the conditional check and the kthread_unpark() will access invalid rdp's->nocb_cb_kthread pointer. This commit therefore use rdp's->nocb_gp_kthread instead of rdp_gp's->nocb_gp_kthread for safety check. Signed-off-by: Zqiang Reviewed-by: Frederic Weisbecker Signed-off-by: Neeraj Upadhyay (AMD) [ Minor conflict resolved. ] Signed-off-by: Jianqiang kang Signed-off-by: Greg Kroah-Hartman --- kernel/rcu/tree_nocb.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -1112,7 +1112,6 @@ static long rcu_nocb_rdp_offload(void *a struct rcu_segcblist *cblist = &rdp->cblist; unsigned long flags; int wake_gp; - struct rcu_data *rdp_gp = rdp->nocb_gp_rdp; WARN_ON_ONCE(rdp->cpu != raw_smp_processor_id()); /* @@ -1122,7 +1121,7 @@ static long rcu_nocb_rdp_offload(void *a if (!rdp->nocb_gp_rdp) return -EINVAL; - if (WARN_ON_ONCE(!rdp_gp->nocb_gp_kthread)) + if (WARN_ON_ONCE(!rdp->nocb_gp_kthread)) return -EINVAL; pr_info("Offloading %d\n", rdp->cpu); @@ -1151,7 +1150,7 @@ static long rcu_nocb_rdp_offload(void *a */ wake_gp = rdp_offload_toggle(rdp, true, flags); if (wake_gp) - wake_up_process(rdp_gp->nocb_gp_kthread); + wake_up_process(rdp->nocb_gp_kthread); swait_event_exclusive(rdp->nocb_state_wq, rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB) && rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP)); Patches currently in stable-queue which might be from jianqkang@sina.cn are queue-6.1/riscv-stacktrace-disable-kasan-checks-for-non-current-tasks.patch queue-6.1/rcu-nocb-fix-possible-invalid-rdp-s-nocb_cb_kthread-pointer-access.patch queue-6.1/io_uring-io-wq-check-io_wq_bit_exit-inside-work-run-loop.patch