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 228EC17E473; Tue, 25 Feb 2025 16:03:41 +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=1740499422; cv=none; b=QDZ2TmD2pybTlKTnCBL3UvSUxps12RmgfVhchX5yv6luSAhpKfUC2nVmAiQqLUuomtr+y5KOeu15+BtNGTkPFoj505moDvX93lmab0DsziLcpxKmWECug+k7GMzc7vPdwR207C0Y9ky783Qsifd167SAZJGIBUPbUk0xmF//hKA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740499422; c=relaxed/simple; bh=PZRqScTDAfxk6yafOLzJqKVISoJHPiEo/RN9hzakm1s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DakxEMIZ3GEanFnf7eG2FDX0FUoUfP1a7jKmGdAPRCyCU7Y7muK8CZG4CXj1Rrd+UkPikl8FyCemgc0vxMixqNj4fS64DNJa0LAvGjEnIqL7olK8gEf4vrytitW8MNS5j1P6TdWR8UIkxNwkevLzyUWP0qlPP2kYG584WUai5Fo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zg+BK2ZN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Zg+BK2ZN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 482EFC4CEDD; Tue, 25 Feb 2025 16:03:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740499421; bh=PZRqScTDAfxk6yafOLzJqKVISoJHPiEo/RN9hzakm1s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Zg+BK2ZNe/cpHw1WeZ2txYRfdHFFu4cwTtPsLhtR2YZG+pHez6IBObAtYUO3a8jl9 XqVYAK7O88nFucQjxhvx1XvyC/u697CpGxKMhyDceAAs55fhBOibEjfRFvGdjfU3pm p4fG6B3PlXiY2vcMlDEPmr3RX+5Dyx90XKldqih4pW1vWLBZq3qDlkddnlDQmRxytY TQ7ef2jr9aL2aucgpewlGfgmH7xPzvTovaF+Jwobf5rqkLbDQk/RB03Nlw6wdv6ks6 r+S02CXubr5GroPFchEgPO//fzaDOgXanGLdP/VU0v5ycy1eM2aCGnAVfFGB4P/VkW 5MuWrP3TZR7YA== Date: Tue, 25 Feb 2025 09:03:38 -0700 From: Keith Busch To: Vlastimil Babka Cc: Uladzislau Rezki , "Paul E. McKenney" , Joel Fernandes , Josh Triplett , Boqun Feng , Christoph Lameter , David Rientjes , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Julia Lawall , Jakub Kicinski , "Jason A. Donenfeld" , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcu@vger.kernel.org, Alexander Potapenko , Marco Elver , Dmitry Vyukov , kasan-dev@googlegroups.com, Jann Horn , Mateusz Guzik , linux-nvme@lists.infradead.org, leitao@debian.org Subject: Re: [PATCH v2 6/7] mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy() Message-ID: References: <20240807-b4-slab-kfree_rcu-destroy-v2-0-ea79102f428c@suse.cz> <20240807-b4-slab-kfree_rcu-destroy-v2-6-ea79102f428c@suse.cz> <2811463a-751f-4443-9125-02628dc315d9@suse.cz> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Feb 25, 2025 at 10:57:38AM +0100, Vlastimil Babka wrote: > I tried to create a kunit test for it, but it doesn't trigger anything. Maybe > it's too simple, or racy, and thus we are not flushing any of the queues from > kvfree_rcu_barrier()? Thanks, your test readily triggers it for me, but only if I load rcutorture at the same time. [ 142.223220] CPU: 11 UID: 0 PID: 186 Comm: kworker/u64:11 Tainted: G E N 6.13.0-04839-g5e7b40f0ddce-dirty #831 [ 142.223222] Tainted: [E]=UNSIGNED_MODULE, [N]=TEST [ 142.223223] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 142.223224] Workqueue: test_kfree_rcu_destroy_wq cache_destroy_workfn [slub_kunit] [ 142.223230] Call Trace: [ 142.223231] [ 142.223233] dump_stack_lvl+0x64/0x90 [ 142.223239] print_circular_bug+0x2c5/0x400 [ 142.223243] check_noncircular+0x103/0x120 [ 142.223246] ? save_trace+0x3e/0x360 [ 142.223249] __lock_acquire+0x1481/0x24b0 [ 142.223252] lock_acquire+0xaa/0x2a0 [ 142.223253] ? console_lock_spinning_enable+0x3e/0x60 [ 142.223255] ? lock_release+0xb3/0x250 [ 142.223257] console_lock_spinning_enable+0x5a/0x60 [ 142.223258] ? console_lock_spinning_enable+0x3e/0x60 [ 142.223260] console_flush_all+0x2b1/0x490 [ 142.223262] ? console_flush_all+0x29/0x490 [ 142.223264] console_unlock+0x49/0xf0 [ 142.223266] vprintk_emit+0x12b/0x300 [ 142.223269] ? kfree_rcu_shrink_scan+0x120/0x120 [ 142.223270] _printk+0x48/0x50 [ 142.223272] ? kfree_rcu_shrink_scan+0x120/0x120 [ 142.223273] __warn_printk+0xb4/0xe0 [ 142.223276] ? 0xffffffffa05d6000 [ 142.223278] ? kfree_rcu_shrink_scan+0x120/0x120 [ 142.223279] check_flush_dependency.part.0+0xad/0x100 [ 142.223282] __flush_work+0x38a/0x4a0 [ 142.223284] ? find_held_lock+0x2b/0x80 [ 142.223287] ? flush_rcu_work+0x26/0x40 [ 142.223289] ? lock_release+0xb3/0x250 [ 142.223290] ? __mutex_unlock_slowpath+0x2c/0x270 [ 142.223292] flush_rcu_work+0x30/0x40 [ 142.223294] kvfree_rcu_barrier+0xe9/0x130 [ 142.223296] kmem_cache_destroy+0x2b/0x1f0 [ 142.223297] cache_destroy_workfn+0x20/0x40 [slub_kunit] [ 142.223299] process_one_work+0x1cd/0x560 [ 142.223302] worker_thread+0x183/0x310 [ 142.223304] ? rescuer_thread+0x330/0x330 [ 142.223306] kthread+0xd8/0x1d0 [ 142.223308] ? ret_from_fork+0x17/0x50 [ 142.223310] ? lock_release+0xb3/0x250 [ 142.223311] ? kthreads_online_cpu+0xf0/0xf0 [ 142.223313] ret_from_fork+0x2d/0x50 [ 142.223315] ? kthreads_online_cpu+0xf0/0xf0 [ 142.223317] ret_from_fork_asm+0x11/0x20 [ 142.223321] [ 142.371052] workqueue: WQ_MEM_RECLAIM test_kfree_rcu_destroy_wq:cache_destroy_workfn [slub_kunit] is flushing !WQ_MEM_RECLAIM events_unbound:kfree_rcu_work [ 142.371072] WARNING: CPU: 11 PID: 186 at kernel/workqueue.c:3715 check_flush_dependency.part.0+0xad/0x100 [ 142.375748] Modules linked in: slub_kunit(E) rcutorture(E) torture(E) kunit(E) iTCO_wdt(E) iTCO_vendor_support(E) intel_uncore_frequency_common(E) skx_edac_common(E) nfit(E) libnvdimm(E) kvm_intel(E) kvm(E) evdev(E) bochs(E) serio_raw(E) drm_kms_helper(E) i2c_i801(E) e1000e(E) i2c_smbus(E) intel_agp(E) intel_gtt(E) lpc_ich(E) agpgart(E) mfd_core(E) drm_shm]