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 E2FB33B2D23 for ; Tue, 12 May 2026 14:18:48 +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=1778595529; cv=none; b=vGdV+CqpDpl74xxC+mIfvhGaKFHmmlR8LBsjbOKs4lQnEhvzOvlmALmevOMCcVO+j2KHjiOXgvrPbsWzRMif42fWeOZ0DUkj45FhLpcKRecNvM6nBDehWFmBIC6uPO2L6C6gI1eSCjgWmOqJ8tGKgt0sGLJeG/fwvhLr5WGOy+E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778595529; c=relaxed/simple; bh=Ju4jT0lNMn/Bkm9nCowCyosL/5of+lK3OoigCJXfW+4=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=LakSVFX2hyCKIgxAAyVhifQCCa6UqDodXnfi00uXccTHvox6DZQnQNhuG5Khnlls5gepBV+MX6H5zwO7y/o2bnv3CBSmB0sUdP/JhpZSYA+3R41Xbg8p9qELHUIJXO8N4kR2yvKDflWDIfKwQPWyJ5ng90VwgAIt/rNjJYS0VUE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nxKFaj7o; 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="nxKFaj7o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 380CAC2BCFA; Tue, 12 May 2026 14:18:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778595528; bh=Ju4jT0lNMn/Bkm9nCowCyosL/5of+lK3OoigCJXfW+4=; h=Subject:To:Cc:From:Date:From; b=nxKFaj7ogfn5Tc4L4UhqlLdd27VVeW4tD8lf5a8wXQoVn4hXMQcw5NDVHWczm17WA m+ulMTFuBdQSPy2lw4HOXHFIqgkcjpXvIn+cs2xjATBekJuHMqzGlnFt+ReCuhOsQw IVA7t9tg8Ahxta7pT7Q34Hk9oIv0dpQL9ZomOqCI= Subject: FAILED: patch "[PATCH] sched_ext: Pass held rq to SCX_CALL_OP() for" failed to apply to 6.18-stable tree To: tj@kernel.org,arighi@nvidia.com,clm@meta.com Cc: From: Date: Tue, 12 May 2026 16:18:23 +0200 Message-ID: <2026051223-catfight-unfounded-5cda@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y git checkout FETCH_HEAD git cherry-pick -x 207d76a372fb1bb324eadc8cb5bcaa0a8da7cefd # git commit -s git send-email --to '' --in-reply-to '2026051223-catfight-unfounded-5cda@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 207d76a372fb1bb324eadc8cb5bcaa0a8da7cefd Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 24 Apr 2026 14:31:36 -1000 Subject: [PATCH] sched_ext: Pass held rq to SCX_CALL_OP() for dump_cpu/dump_task scx_dump_state() walks CPUs with rq_lock_irqsave() held and invokes ops.dump_cpu / ops.dump_task with NULL locked_rq, leaving scx_locked_rq_state NULL. If the BPF callback calls a kfunc that re-acquires rq based on scx_locked_rq() - e.g. scx_bpf_cpuperf_set(cpu) - it re-acquires the already-held rq. Pass the held rq to SCX_CALL_OP(). Thread it into scx_dump_task() too. The pre-loop ops.dump call runs before rq_lock_irqsave() so keeps rq=NULL. Fixes: 07814a9439a3 ("sched_ext: Print debug dump after an error exit") Cc: stable@vger.kernel.org # v6.12+ Reported-by: Chris Mason Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 26968d0a6752..73d629559d6d 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -6117,9 +6117,8 @@ static void ops_dump_exit(void) scx_dump_data.cpu = -1; } -static void scx_dump_task(struct scx_sched *sch, - struct seq_buf *s, struct scx_dump_ctx *dctx, - struct task_struct *p, char marker) +static void scx_dump_task(struct scx_sched *sch, struct seq_buf *s, struct scx_dump_ctx *dctx, + struct rq *rq, struct task_struct *p, char marker) { static unsigned long bt[SCX_EXIT_BT_LEN]; struct scx_sched *task_sch = scx_task_sched(p); @@ -6160,7 +6159,7 @@ static void scx_dump_task(struct scx_sched *sch, if (SCX_HAS_OP(sch, dump_task)) { ops_dump_init(s, " "); - SCX_CALL_OP(sch, dump_task, NULL, dctx, p); + SCX_CALL_OP(sch, dump_task, rq, dctx, p); ops_dump_exit(); } @@ -6284,8 +6283,7 @@ static void scx_dump_state(struct scx_sched *sch, struct scx_exit_info *ei, used = seq_buf_used(&ns); if (SCX_HAS_OP(sch, dump_cpu)) { ops_dump_init(&ns, " "); - SCX_CALL_OP(sch, dump_cpu, NULL, - &dctx, cpu, idle); + SCX_CALL_OP(sch, dump_cpu, rq, &dctx, cpu, idle); ops_dump_exit(); } @@ -6308,11 +6306,11 @@ static void scx_dump_state(struct scx_sched *sch, struct scx_exit_info *ei, if (rq->curr->sched_class == &ext_sched_class && (dump_all_tasks || scx_task_on_sched(sch, rq->curr))) - scx_dump_task(sch, &s, &dctx, rq->curr, '*'); + scx_dump_task(sch, &s, &dctx, rq, rq->curr, '*'); list_for_each_entry(p, &rq->scx.runnable_list, scx.runnable_node) if (dump_all_tasks || scx_task_on_sched(sch, p)) - scx_dump_task(sch, &s, &dctx, p, ' '); + scx_dump_task(sch, &s, &dctx, rq, p, ' '); next: rq_unlock_irqrestore(rq, &rf); }