Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760000AbZIPU5W (ORCPT ); Wed, 16 Sep 2009 16:57:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754503AbZIPU5R (ORCPT ); Wed, 16 Sep 2009 16:57:17 -0400 Received: from mail-fx0-f217.google.com ([209.85.220.217]:40729 "EHLO mail-fx0-f217.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754252AbZIPU5R (ORCPT ); Wed, 16 Sep 2009 16:57:17 -0400 Date: Wed, 16 Sep 2009 20:57:17 +0000 From: Frederik Deweerdt To: Lars Ericsson Cc: David.Woodhouse@intel.com, sachinp@in.ibm.com, linux-kernel@vger.kernel.org Subject: Re: Oops in drivers\base\firmware_class Message-ID: <20090916205717.GB12117@gambetta> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6941 Lines: 140 Hello Lars, On Wed, Sep 16, 2009 at 08:44:43PM +0200, Lars Ericsson wrote: > Hi, > > I have discovered a Oops in the firmware_loading_store function. > At first it looks like a timing issue but after adding a BUG_ON test, > it fails every time. > > drivers\base\firmware_class: > ------------------------------ > 541 01c0 F6463401 testb $1,52(%esi) > 542 01c4 0F843FFF je .L38 > 542 FFFF > 543 .loc 1 174 0 > 544 01ca 8B4630 movl 48(%esi),%eax > 545 01cd 8B4004 movl 4(%eax),%eax <---- Oops > 546 01d0 E8FCFFFF call vfree > 546 FF > > The code that fails was introduced in commit > 6e03a201bbe8137487f340d26aa662110e324b20 Could you try the following patch? It seems that we're missing the locking around the accesses to fw_priv->fw. Thanks, Frederik Signed-off-by: Frederik Deweerdt diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 8a267c4..49105ed 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -171,12 +171,18 @@ static ssize_t firmware_loading_store(struct device *dev, break; case 0: if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) { + mutex_lock(&fw_lock); + if (!fw_priv->fw) { + mutex_unlock(&fw_lock); + break; + } vfree(fw_priv->fw->data); fw_priv->fw->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0, PAGE_KERNEL_RO); if (!fw_priv->fw->data) { dev_err(dev, "%s: vmap() failed\n", __func__); + mutex_unlock(&fw_lock); goto err; } /* Pages will be freed by vfree() */ @@ -185,6 +191,7 @@ static ssize_t firmware_loading_store(struct device *dev, fw_priv->nr_pages = 0; complete(&fw_priv->completion); clear_bit(FW_STATUS_LOADING, &fw_priv->status); + mutex_unlock(&fw_lock); break; } /* fallthrough */ > > Attached you will find the: > - Oops with the vanilla 2.6.31 > - The BUG_ON patch > - Oops with the patched 2.6.31 > > /Lars > [ 7.249453] rt61pci 0000:00:09.0: firmware: requesting rt2561s.bin > [ 7.314512] BUG: unable to handle kernel NULL pointer dereference at 00000004 > [ 7.315639] IP: [] firmware_loading_store+0xed/0x160 [firmware_class] > [ 7.315639] *pde = 00000000 > [ 7.315639] Oops: 0000 [#1] PREEMPT > [ 7.315639] last sysfs file: /sys/devices/pci0000:00/0000:00:09.0/firmware/0000:00:09.0/loading > [ 7.315639] Modules linked in: arc4 ecb cryptomgr crypto_blkcipher aead pcompress crypto_hash crypto_algapi rt61pci rt2x00pci rt2x00lib firmware_class mac80211 input_polldev crc_itu_t eeprom_93cx6 cfg80211 ndccanram ndccan ndcser(P) ndcscan(P) eu16550(P) ndccon(P) > [ 7.315639] > [ 7.315639] Pid: 1004, comm: echo Tainted: P (2.6.31 #1) > [ 7.315639] EIP: 0060:[] EFLAGS: 00010202 CPU: 0 > [ 7.315639] EIP is at firmware_loading_store+0xed/0x160 [firmware_class] > [ 7.315639] EAX: 00000000 EBX: d04d50e0 ECX: 0000000a EDX: 00000028 > [ 7.315639] ESI: cf65ca80 EDI: cea29c00 EBP: cea29c08 ESP: cf777f2c > [ 7.315639] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 > [ 7.315639] Process echo (pid: 1004, ti=cf776000 task=cf755aa0 task.ti=cf776000) > [ 7.315639] Stack: > [ 7.315639] d04d50e0 cea29c00 00000002 c028051d 00000002 c0414c40 ce9c0420 c01c9c98 > [ 7.315639] <0> 00000002 c0414c40 00000002 b7f15000 ce9c1e80 cf44c000 c01c9ce6 ce9c1e94 > [ 7.315639] <0> cf44c000 b7f15000 00000002 c01c9cb0 c018d362 cf777f9c cf44c000 fffffff7 > [ 7.315639] Call Trace: > [ 7.315639] [] ? firmware_loading_store+0x0/0x160 [firmware_class] > [ 7.315639] [] ? dev_attr_store+0x1d/0x20 > [ 7.315639] [] ? flush_write_buffer+0x38/0x50 > [ 7.315639] [] ? sysfs_write_file+0x36/0x60 > [ 7.315639] [] ? sysfs_write_file+0x0/0x60 > [ 7.315639] [] ? vfs_write+0x82/0xf0 > [ 7.315639] [] ? sys_write+0x3c/0x70 > [ 7.315639] [] ? syscall_call+0x7/0xb > [ 7.315639] Code: 91 c9 ef 3b 5e 3c 7c ed eb b5 8d 74 26 00 83 f8 ff 0f 85 50 ff ff ff e9 6a ff ff ff 89 f6 f6 46 34 01 0f 84 3f ff ff ff 8b 46 30 <8b> 40 04 e8 5b 05 cb ef 31 c9 8b 56 3c 8b 46 38 8b 5e 30 68 61 > [ 7.315639] EIP: [] firmware_loading_store+0xed/0x160 [firmware_class] SS:ESP 0068:cf777f2c > [ 7.315639] CR2: 0000000000000004 > [ 7.540848] ---[ end trace 6ebe83c102d3b046 ]--- > [ 7.242449] ------------[ cut here ]------------ > [ 7.243706] Kernel BUG at d04d523e [verbose debug info unavailable] > [ 7.243706] invalid opcode: 0000 [#1] PREEMPT > [ 7.243706] last sysfs file: /sys/devices/pci0000:00/0000:00:09.0/firmware/0000:00:09.0/loading > [ 7.243706] Modules linked in: arc4 ecb cryptomgr crypto_blkcipher aead pcompress crypto_hash crypto_algapi rt61pci rt2x00pci rt2x00lib firmware_class mac80211 input_polldev crc_itu_t eeprom_93cx6 cfg80211 ndccanram ndccan ndcser(P) ndcscan(P) eu16550(P) ndccon(P) > [ 7.243706] > [ 7.243706] Pid: 1004, comm: echo Tainted: P (2.6.31 #1) > [ 7.243706] EIP: 0060:[] EFLAGS: 00010246 CPU: 0 > [ 7.243706] EIP is at firmware_loading_store+0x15e/0x170 [firmware_class] > [ 7.243706] EAX: 00000000 EBX: d04d50e0 ECX: 0000000a EDX: 00000028 > [ 7.243706] ESI: cf4f2a20 EDI: cf4ffc00 EBP: cf4ffc08 ESP: cea37f2c > [ 7.243706] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 > [ 7.243706] Process echo (pid: 1004, ti=cea36000 task=cf6c2380 task.ti=cea36000) > [ 7.243706] Stack: > [ 7.243706] d04d50e0 cf4ffc00 00000002 c028051d 00000002 c0414c40 cf4fd420 c01c9c98 > [ 7.243706] <0> 00000002 c0414c40 00000002 b7fc8000 cf636e80 cf471980 c01c9ce6 cf636e94 > [ 7.243706] <0> cf471980 b7fc8000 00000002 c01c9cb0 c018d362 cea37f9c cf471980 fffffff7 > [ 7.243706] Call Trace: > [ 7.243706] [] ? firmware_loading_store+0x0/0x170 [firmware_class] > [ 7.243706] [] ? dev_attr_store+0x1d/0x20 > [ 7.243706] [] ? flush_write_buffer+0x38/0x50 > [ 7.243706] [] ? sysfs_write_file+0x36/0x60 > [ 7.243706] [] ? sysfs_write_file+0x0/0x60 > [ 7.243706] [] ? vfs_write+0x82/0xf0 > [ 7.243706] [] ? sys_write+0x3c/0x70 > [ 7.243706] [] ? syscall_call+0x7/0xb > [ 7.243706] Code: 66 34 fe e9 14 ff ff ff 8b 47 08 68 1c 5f 4d d0 50 89 f8 e8 65 b2 da ef 50 68 c3 5f 4d d0 e8 da 3c c5 ef 83 c4 10 e9 ea fe ff ff <0f> 0b eb fe 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 55 89 cd > [ 7.243706] EIP: [] firmware_loading_store+0x15e/0x170 [firmware_class] SS:ESP 0068:cea37f2c > [ 7.458557] ---[ end trace 604593037057054f ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/