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 A198D3A3830 for ; Thu, 21 May 2026 12:57:56 +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=1779368277; cv=none; b=M2rMNrwH+X+0iCwrw9ksojK8/O2gz4rZvOnY043tcp6RaqA3K4VSab57Bocd18s1huANQhTxgm/aS9898MjGpmT6psStSVlo8ibjcDzZoAqyb8dWe/r/Rr6Dva0bDuSm/9QGVZtHQPo/DrRWyqlv5JMU/Gdx26k76GB/HTowiCQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779368277; c=relaxed/simple; bh=/CuhVwU/w07Qcw2gC+ELJ/a144Zl5BOnW9ipwqbMK9o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OrSuROGyDfQpo+ibjH0PbsVeDftIN+1aPYG3GmyEjo0cWxAxNMoMUwMMgV+/oYTOJVFWqyr1foF7Zi+XahYAUXNY2sa1RauXg/TOXL9cHe97YU7XqcJuw0LGupYKgerg+z+g1y8BbqAdSQbLqCZZioX58K6YJ7yHKKwvQlxp+1s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kbxfYqZM; 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="kbxfYqZM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7FF21F00A3C; Thu, 21 May 2026 12:57:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779368276; bh=8Q7nzUFVJbD6sXdtCSmhHSlGfU+IDd31q0R03rAFoQI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kbxfYqZMhvrHnzsymzbOHGrojNdNa/9bcKTdN/UssI18vzFe34woxRWU/nRlItTGf AtkCCqT0kvsYENqKYaf89APBsxNOUhddfYWXBr+MMXbD8RACWEHGrAbW+/hZAivHSC 4ehjSVgB8n0s8CpC8tUTgTBFdtTYAnES24EtkDGwiPS+KH9cn2c5NgJ5mWCWhBa/Ai ATee41ZM7sjUzfJmb+UK9LdADGf1Ja90tDFf1raNlBz61ZqK5LQvcYWrqUyYzQ9OeP NOWNPNJepZX5detDcn+Eutw/jYNB9NQXO9C1tG0L3nQy8ZO34OP6JxHGynbsOFsff2 Ny0MLMCWmkCDw== From: Sasha Levin To: stable@vger.kernel.org Cc: Tejun Heo , Sashiko , Sasha Levin Subject: [PATCH 7.0.y 2/2] sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path Date: Thu, 21 May 2026 08:57:53 -0400 Message-ID: <20260521125753.1164691-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260521125753.1164691-1-sashal@kernel.org> References: <2026051526-prelude-boil-36f5@gregkh> <20260521125753.1164691-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tejun Heo [ Upstream commit 9a415cc53711f2238e0f0ca8a6bcc796c003b127 ] In scx_root_enable_workfn(), put_task_struct(p) is called before scx_error() dereferences p->comm and p->pid. If the iterator's reference is the last drop, the task is freed synchronously and the deref becomes a UAF. Move put_task_struct() past scx_error(). Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260511214031.AF5E9C2BCB0@smtp.kernel.org/ Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Cc: stable@vger.kernel.org # v6.12+ Signed-off-by: Tejun Heo [ kept `scx_init_task()` call site instead of `__scx_init_task()`/`task_rq_lock` ] Signed-off-by: Sasha Levin --- kernel/sched/ext.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index ec4a1d754d211..3a8f2b338ae89 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -5239,10 +5239,10 @@ static void scx_enable_workfn(struct kthread_work *work) ret = scx_init_task(p, task_group(p), false); if (ret) { - put_task_struct(p); scx_task_iter_stop(&sti); scx_error(sch, "ops.init_task() failed (%d) for %s[%d]", ret, p->comm, p->pid); + put_task_struct(p); goto err_disable_unlock_all; } -- 2.53.0