From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753747AbdHEAJN (ORCPT ); Fri, 4 Aug 2017 20:09:13 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46608 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753219AbdHDXRn (ORCPT ); Fri, 4 Aug 2017 19:17:43 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brian Norris , Kees Cook Subject: [PATCH 4.9 042/105] pstore: Correctly initialize spinlock and flags Date: Fri, 4 Aug 2017 16:15:10 -0700 Message-Id: <20170804231554.460571506@linuxfoundation.org> X-Mailer: git-send-email 2.13.4 In-Reply-To: <20170804231551.544678194@linuxfoundation.org> References: <20170804231551.544678194@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 76d5692a58031696e282384cbd893832bc92bd76 upstream. The ram backend wasn't always initializing its spinlock correctly. Since it was coming from kzalloc memory, though, it was harmless on architectures that initialize unlocked spinlocks to 0 (at least x86 and ARM). This also fixes a possibly ignored flag setting too. When running under CONFIG_DEBUG_SPINLOCK, the following Oops was visible: [ 0.760836] persistent_ram: found existing buffer, size 29988, start 29988 [ 0.765112] persistent_ram: found existing buffer, size 30105, start 30105 [ 0.769435] persistent_ram: found existing buffer, size 118542, start 118542 [ 0.785960] persistent_ram: found existing buffer, size 0, start 0 [ 0.786098] persistent_ram: found existing buffer, size 0, start 0 [ 0.786131] pstore: using zlib compression [ 0.790716] BUG: spinlock bad magic on CPU#0, swapper/0/1 [ 0.790729] lock: 0xffffffc0d1ca9bb0, .magic: 00000000, .owner: /-1, .owner_cpu: 0 [ 0.790742] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc2+ #913 [ 0.790747] Hardware name: Google Kevin (DT) [ 0.790750] Call trace: [ 0.790768] [] dump_backtrace+0x0/0x2bc [ 0.790780] [] show_stack+0x20/0x28 [ 0.790794] [] dump_stack+0xa4/0xcc [ 0.790809] [] spin_dump+0xe0/0xf0 [ 0.790821] [] spin_bug+0x30/0x3c [ 0.790834] [] do_raw_spin_lock+0x50/0x1b8 [ 0.790846] [] _raw_spin_lock_irqsave+0x54/0x6c [ 0.790862] [] buffer_size_add+0x48/0xcc [ 0.790875] [] persistent_ram_write+0x60/0x11c [ 0.790888] [] ramoops_pstore_write_buf+0xd4/0x2a4 [ 0.790900] [] pstore_console_write+0xf0/0x134 [ 0.790912] [] console_unlock+0x48c/0x5e8 [ 0.790923] [] register_console+0x3b0/0x4d4 [ 0.790935] [] pstore_register+0x1a8/0x234 [ 0.790947] [] ramoops_probe+0x6b8/0x7d4 [ 0.790961] [] platform_drv_probe+0x7c/0xd0 [ 0.790972] [] driver_probe_device+0x1b4/0x3bc [ 0.790982] [] __device_attach_driver+0xc8/0xf4 [ 0.790996] [] bus_for_each_drv+0xb4/0xe4 [ 0.791006] [] __device_attach+0xd0/0x158 [ 0.791016] [] device_initial_probe+0x24/0x30 [ 0.791026] [] bus_probe_device+0x50/0xe4 [ 0.791038] [] device_add+0x3a4/0x76c [ 0.791051] [] of_device_add+0x74/0x84 [ 0.791062] [] of_platform_device_create_pdata+0xc0/0x100 [ 0.791073] [] of_platform_device_create+0x34/0x40 [ 0.791086] [] of_platform_default_populate_init+0x58/0x78 [ 0.791097] [] do_one_initcall+0x88/0x160 [ 0.791109] [] kernel_init_freeable+0x264/0x31c [ 0.791123] [] kernel_init+0x18/0x11c [ 0.791133] [] ret_from_fork+0x10/0x50 [ 0.793717] console [pstore-1] enabled [ 0.797845] pstore: Registered ramoops as persistent store backend [ 0.804647] ramoops: attached 0x100000@0xf7edc000, ecc: 0/0 Fixes: 663deb47880f ("pstore: Allow prz to control need for locking") Fixes: 109704492ef6 ("pstore: Make spinlock per zone instead of global") Reported-by: Brian Norris Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ram_core.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -467,8 +467,7 @@ static int persistent_ram_buffer_map(phy } static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, - struct persistent_ram_ecc_info *ecc_info, - unsigned long flags) + struct persistent_ram_ecc_info *ecc_info) { int ret; @@ -494,10 +493,9 @@ static int persistent_ram_post_init(stru prz->buffer->sig); } + /* Rewind missing or invalid memory area. */ prz->buffer->sig = sig; persistent_ram_zap(prz); - prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); - prz->flags = flags; return 0; } @@ -533,11 +531,15 @@ struct persistent_ram_zone *persistent_r goto err; } + /* Initialize general buffer state. */ + prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); + prz->flags = flags; + ret = persistent_ram_buffer_map(start, size, prz, memtype); if (ret) goto err; - ret = persistent_ram_post_init(prz, sig, ecc_info, flags); + ret = persistent_ram_post_init(prz, sig, ecc_info); if (ret) goto err;