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 A33E03FB7C1 for ; Thu, 18 Jun 2026 12:59:08 +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=1781787549; cv=none; b=VZD7EYNiaVh7JFM5n4PnKkvkikZOoKyCxO7FWPxEv/Z+Ml0BeH+JCjcTx6Zkom2i6ES4nelfVwkuBB8/1caa6W4HUrC8VnrtfWVOY+jRGAIJg79ZPESotd3iYy3zkW8ZTabsPT4IKl07vKlCwpxKeEwCQYGJtD73pj/m1BVUH1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781787549; c=relaxed/simple; bh=3u28dOZ17z3lY2ld5kI9JAJCrBjQ8mKIKIo2A+jdFSo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uSvefW0O4/VyRP2rlenKg5ZNk3PoQSN/yP73oWFIUB1RZrgu7e0Qvgvw5sezxSrQwTKnvcUIBd9kAYvwl+nuSzSQ5Q3TNl9FezX9tdGhczCR7tep5yVx/QI9WDghc7oy0R2ZAczTmrGXsdVxvma5Z0Tt4s2A3oPfT6+vlIxDuLg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K7rFxqw7; 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="K7rFxqw7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C14A21F00A3E; Thu, 18 Jun 2026 12:59:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781787548; bh=VstLiPMnjfvNE/Mxd6qPpD+dL0zzEfyFsXb2dE5MLSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K7rFxqw7dsjBH8j+ifnvxPTgCEDFjmzDReGzekVf93lW74bP7Scz69m+tht3wQ1RL SyDzMVvxo6yiP6evmg1pdC/Eoi0yAoVzOYZLsHOCXDAMyPI17axDB/Dd0xsjRGdDO8 rIgY7Dsg5lxusjrUrapWeAMauzSxNIUciCP4VMpi9YHYDfyvg9Gog7SOuCUi2ZU4To qHy53p8flCHGueoGgJX4Otpv5ffHg6580yCsgBmONa6rijKP2313/fr4SVReptVPZe d3YX5Vm1u/qKp/sOWHOTK4R2C/7K/GPVWxeJopbHPdHUjjkxAhlsAk/ASnWrHv6nQM AYG3ziAEBMlqg== From: Sasha Levin To: stable@vger.kernel.org Cc: Helen Koike , syzbot+b8ca586b9fc235f0c0df@syzkaller.appspotmail.com, Thomas Gleixner , Sasha Levin Subject: [PATCH 6.18.y 2/2] debugobjects: Do not fill_pool() if pi_blocked_on Date: Thu, 18 Jun 2026 08:59:05 -0400 Message-ID: <20260618125905.692105-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260618125905.692105-1-sashal@kernel.org> References: <2026061609-grievance-habitat-1c05@gregkh> <20260618125905.692105-1-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: Helen Koike [ Upstream commit 5f41161059fd0f1bbf18c90f3180e38cc45a14eb ] On RT enabled kernels, fill_pool() ends up calling rtlock_lock(), which asserts if current::pi_blocked_on is set, because a task can obviously only block on one lock as otherwise the priority inheritenace chain gets corrupted. Prevent this by expanding the conditional to take current::pi_blocked_on into account. Fixes: 4bedcc28469a ("debugobjects: Make them PREEMPT_RT aware") Reported-by: syzbot+b8ca586b9fc235f0c0df@syzkaller.appspotmail.com Signed-off-by: Helen Koike Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260511215359.3351259-1-koike@igalia.com Closes: https://syzkaller.appspot.com/bug?extid=b8ca586b9fc235f0c0df Signed-off-by: Sasha Levin --- lib/debugobjects.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 9d59b797d1b507..f7fdaec4886aba 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -711,6 +711,15 @@ static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket return NULL; } +static inline bool debug_objects_is_pi_blocked_on(void) +{ +#ifdef CONFIG_RT_MUTEXES + return current->pi_blocked_on != NULL; +#else + return false; +#endif +} + static void debug_objects_fill_pool(void) { if (!static_branch_likely(&obj_cache_enabled)) @@ -727,11 +736,12 @@ static void debug_objects_fill_pool(void) /* * On RT enabled kernels the pool refill must happen in preemptible - * context -- for !RT kernels we rely on the fact that spinlock_t and - * raw_spinlock_t are basically the same type and this lock-type - * inversion works just fine. + * context and not enqueued on an rt_mutex -- for !RT kernels we rely + * on the fact that spinlock_t and raw_spinlock_t are basically the + * same type and this lock-type inversion works just fine. */ - if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() || system_state < SYSTEM_SCHEDULING) { + if (!IS_ENABLED(CONFIG_PREEMPT_RT) || system_state < SYSTEM_SCHEDULING || + (preemptible() && !debug_objects_is_pi_blocked_on())) { /* * Annotate away the spinlock_t inside raw_spinlock_t warning * by temporarily raising the wait-type to WAIT_SLEEP, matching -- 2.53.0