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 E13023E1714 for ; Thu, 21 May 2026 13:54:00 +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=1779371642; cv=none; b=Rb75MnWPQvXeUqVgbkaC7rMMYKJMcwHVUdxhv+QujXdo8Dz4KJ8owcSPr5YfwXbQkHzerP273BwqeS540ktnWOwWZlHqtfuz5S4UMfzCOUELS3hobuj+loZ9bwGKh+8ffDq5unID8Ny49KwcO1FerpK/FwM4CWHIdcey0wI/Y6U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779371642; c=relaxed/simple; bh=VZe5Y7OcO2wmhuOtc1kZX5bb2Smp1K/ilQY7Hv4OO3U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GAQdHwWIqpf8EQDz6LpyC1tNUty6lYzJVYmCF3dUdMTu+GXSZ0Whw/MekBkiENYBU+2qK9pzSRkUOnghqR3NF+AjR6yEZi0VfpzEekJfU0KUR+D/ppdsDUVWTOosmKauT7yRHCtqe3FL5ZsKy5NzZC6w+QmLOANWf/MocP3gPqc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JQhlhfy4; 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="JQhlhfy4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C802F1F00A3D; Thu, 21 May 2026 13:53:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779371640; bh=rAG3J1i1IuFwBGPtKIZLa7BjulHtcp2mfMZsJMf8GHI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JQhlhfy4U2KNpKpqwSgGHI9anLwPUHNlhCOt6lu5CYE9LjkHEQ+jgw3VNAyofGvF5 k7fPb74wz+ucCuJwImQyNAooKCwgzvCVecPAiHmOZg+oVk+KEGKW74Fb3hwV1cmBQV Fu1WVH6WTH/r+TfrRT81fWVl6K7O64nfxAp57PPOF9gEQbLeRGJl/9mt+MBMDj+fiu 3uEvsuPnmFXgVpokoNmdzXiArMbK55qg7ho/HUmKBNGV9yK2aQL+y2ZNRjvzYxtBWz Aadrr/NPcvzO33kA8DQNXRg05iaW4AcTr8hgIYEWwmvc0k1l+ubQYNEr5dwlQgh9/x o5ooPLImGTdSA== From: Sasha Levin To: stable@vger.kernel.org Cc: Samuele Mariotti , Paolo Valente , Andrea Righi , Tejun Heo , Sasha Levin Subject: [PATCH 6.18.y 1/2] sched_ext: Fix missing warning in scx_set_task_state() default case Date: Thu, 21 May 2026 09:53:57 -0400 Message-ID: <20260521135358.1280483-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026051526-vastness-flattop-e72e@gregkh> References: <2026051526-vastness-flattop-e72e@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Samuele Mariotti [ Upstream commit b905ee77d5f557a83a485b4146210f54f13365fc ] In scx_set_task_state(), the default case was setting the warn flag, but then returning immediately. This is problematic because the only purpose of the warn flag is to trigger WARN_ONCE, but the early return prevented it from ever firing, leaving invalid task states undetected and untraced. To fix this, a WARN_ONCE call is now added directly in the default case. The fix addresses two aspects: - Guarantees the invalid task states are properly logged and traced. - Provides a distinct warning message ("sched_ext: Invalid task state") specifically for states outside the defined scx_task_state enum values, making it easier to distinguish from other transition warnings. This ensures proper detection and reporting of invalid states. Signed-off-by: Samuele Mariotti Signed-off-by: Paolo Valente Reviewed-by: Andrea Righi Signed-off-by: Tejun Heo Stable-dep-of: 9a415cc53711 ("sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path") Signed-off-by: Sasha Levin --- kernel/sched/ext.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 177bbf31116d0..54621f6226886 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2800,7 +2800,8 @@ static void scx_set_task_state(struct task_struct *p, enum scx_task_state state) warn = prev_state != SCX_TASK_READY; break; default: - warn = true; + WARN_ONCE(1, "sched_ext: Invalid task state %d -> %d for %s[%d]", + prev_state, state, p->comm, p->pid); return; } -- 2.53.0