From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6C8BA2BEFEB; Sat, 25 Jul 2026 00:50:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784940624; cv=none; b=m4iD5n9sVJhG5ccF6tVw0nDs2V8mEBAsD0HyW+ieyh3i8HSlFjDY2a6vom/2AlwDeF1Y0PRHzNzZJgnCM5xZMBUyMvZq8FereUQ+fRptM6K4kNn/4M9Hp1AWtn2iGFB6MgAeOCtxbLzj35IIkyqudDKCbQw9pUAIGT9YlmPB6Ng= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784940624; c=relaxed/simple; bh=U2YaFMMABy+NgO0Ne31k2KgBEx7woo2aToivNws208o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Xw9MUOIiPLKq+nOdYez9oUQ26tzfXP80hjq7kHh6Vz/n2OGmo4tERILPk1be2zys3wVPnpbMxjMdoOuRqS9P6gocjhibex6TbMcbo6aOgmsMvYBHAAfvsTdVIBcPL3zIAoafpcwZV/BMhqGdPI3z9idrubmAEnUu5dLTJzpBcCk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KkSjI4TS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KkSjI4TS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E34871F00A3A; Sat, 25 Jul 2026 00:50:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784940623; bh=V8QdcNYMKnGDOJkuOriwtS3IYUCaZznC2QPPFiXjK04=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KkSjI4TSRH4o+bbbURpr8JF6W39G/7ggtwoBY/vR6prggxZjG3U+X6CNzZOaLFJ3x YaHMMTF0eed2JUm76Bh6RkNGhfPXUwxnzPbLdMHX0ucWTj7KRmbcGEVGPRs6mTXK0B pFxIZx+qbFp29VLj9/j/DOmBaR6+TnAQ+D6pFraRR9SdzX1mxXwoMSi2zBlb3xofYK miX9/b0cur+SjE+IGPX93AX7nyTNsBeS5EcszdO2Y9ZpyZss65cU7lbJTrMMCJL17W R3oKJtbVxfWg4a1UmTEx8X79iPH5Q3qagP1w6HnaA2TgBvrTDHHl1QJ2mAMxHvjGUI H9w4A9J7WmQzw== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: sched-ext@lists.linux.dev, Emil Tsalapatis , linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 3/5] sched_ext: Report NMI kicks with scx_error() Date: Fri, 24 Jul 2026 14:50:17 -1000 Message-ID: <20260725005019.1297049-4-tj@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260725005019.1297049-1-tj@kernel.org> References: <20260725005019.1297049-1-tj@kernel.org> Precedence: bulk X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The per-cpu kick lists are protected by IRQ masking which doesn't stop NMIs, so scx_bpf_kick_cpu() from NMI silently drops the kick after a one-time warning. A dropped kick can leave a CPU idle when the scheduler believes it was woken, which is a correctness problem for the scheduler even if the kernel is fine. Now that scx_error() works from NMI, abort the scheduler instead so that the bug is surfaced deterministically. The warned_nmi_kick tracking is no longer needed. Signed-off-by: Tejun Heo --- kernel/sched/ext/ext.c | 6 +----- kernel/sched/ext/internal.h | 1 - 2 files changed, 1 insertion(+), 6 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 29ca5f5ec30b..4338dc6a3f3a 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -9208,11 +9208,7 @@ void scx_kick_cpu(struct scx_sched *sch, s32 cpu, u64 flags) * not mask NMIs, so kicking from NMI could corrupt it and is unsupported. */ if (unlikely(in_nmi())) { - if (!sch->warned_nmi_kick) { - sch->warned_nmi_kick = true; - pr_warn("sched_ext: %s: scx_bpf_kick_cpu() from NMI ignored\n", - sch->ops.name); - } + scx_error(sch, "scx_bpf_kick_cpu() called from NMI"); return; } diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h index a0659f74b065..b141f0104b44 100644 --- a/kernel/sched/ext/internal.h +++ b/kernel/sched/ext/internal.h @@ -1546,7 +1546,6 @@ struct scx_sched { */ bool warned_zero_slice:1; bool warned_unassoc_progs:1; - bool warned_nmi_kick:1; struct list_head all; -- 2.55.0