From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754225AbeAQQte (ORCPT ); Wed, 17 Jan 2018 11:49:34 -0500 Received: from mail-ot0-f195.google.com ([74.125.82.195]:43696 "EHLO mail-ot0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753715AbeAQQtc (ORCPT ); Wed, 17 Jan 2018 11:49:32 -0500 X-Google-Smtp-Source: ACJfBovTdVNmxN4UAkpwA++8TvdWny8ipnazggrZie7mqvtex45fKTbo/3zwtr9gBiE5JE+hS6C1Ow== Reply-To: minyard@acm.org Subject: Re: [PATCH] ipmi: use dynamic memory for DMI driver override To: John Garry , openipmi-developer@lists.sourceforge.net Cc: linuxarm@huawei.com, linux-kernel@vger.kernel.org References: <1516207017-158659-1-git-send-email-john.garry@huawei.com> From: Corey Minyard Message-ID: Date: Wed, 17 Jan 2018 10:49:29 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <1516207017-158659-1-git-send-email-john.garry@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/17/2018 10:36 AM, John Garry wrote: > Currently a crash can be seen if we reach the "err" > label in dmi_add_platform_ipmi(), calling > platform_device_put(), like here: > [ 7.270584] (null): ipmi:dmi: Unable to add resources: -16 > [ 7.330229] ------------[ cut here ]------------ > [ 7.334889] kernel BUG at mm/slub.c:3894! > [ 7.338936] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP > [ 7.344475] Modules linked in: > [ 7.347556] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc2-00004-gbe9cb7b-dirty #114 > [ 7.355907] Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT17 Nemo 2.0 RC0 11/29/2017 > [ 7.365137] task: 00000000c211f6d3 task.stack: 00000000f276e9af > [ 7.371116] pstate: 60000005 (nZCv daif -PAN -UAO) > [ 7.375957] pc : kfree+0x194/0x1b4 > [ 7.379389] lr : platform_device_release+0xcc/0xd8 > [ 7.384225] sp : ffff0000092dba90 > [ 7.387567] x29: ffff0000092dba90 x28: ffff000008a83000 > [ 7.392933] x27: ffff0000092dbc10 x26: 00000000000000e6 > [ 7.398297] x25: 0000000000000003 x24: ffff0000085b51e8 > [ 7.403662] x23: 0000000000000100 x22: ffff7e0000234cc0 > [ 7.409027] x21: ffff000008af3660 x20: ffff8017d21acc10 > [ 7.414392] x19: ffff8017d21acc00 x18: 0000000000000002 > [ 7.419757] x17: 0000000000000001 x16: 0000000000000008 > [ 7.425121] x15: 0000000000000001 x14: 6666666678303d65 > [ 7.430486] x13: 6469727265766f5f x12: 7265766972642e76 > [ 7.435850] x11: 6564703e2d617020 x10: 6530326435373638 > [ 7.441215] x9 : 3030303030303030 x8 : 3d76656420657361 > [ 7.446580] x7 : ffff000008f59df8 x6 : ffff8017fbe0ea50 > [ 7.451945] x5 : 0000000000000000 x4 : 0000000000000000 > [ 7.457309] x3 : ffffffffffffffff x2 : 0000000000000000 > [ 7.462674] x1 : 0fffc00000000800 x0 : ffff7e0000234ce0 > [ 7.468039] Process swapper/0 (pid: 1, stack limit = 0x00000000f276e9af) > [ 7.474809] Call trace: > [ 7.477272] kfree+0x194/0x1b4 > [ 7.480351] platform_device_release+0xcc/0xd8 > [ 7.484837] device_release+0x34/0x90 > [ 7.488531] kobject_put+0x70/0xcc > [ 7.491961] put_device+0x14/0x1c > [ 7.495304] platform_device_put+0x14/0x1c > [ 7.499439] dmi_add_platform_ipmi+0x348/0x3ac > [ 7.503923] scan_for_dmi_ipmi+0xfc/0x10c > [ 7.507970] do_one_initcall+0x38/0x124 > [ 7.511840] kernel_init_freeable+0x188/0x228 > [ 7.516238] kernel_init+0x10/0x100 > [ 7.519756] ret_from_fork+0x10/0x18 > [ 7.523362] Code: f94002c0 37780080 f94012c0 37000040 (d4210000) > [ 7.529552] ---[ end trace 11750e4787deef9e ]--- > [ 7.534228] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > [ 7.534228] > > This is because when the device is released in > platform_device_release(), we try to free > pdev.driver_override. This is a const string, hence > the crash. > Fix by using dynamic memory for pdev->driver_override. > > Signed-off-by: John Garry Oops, sorry about that.  Yes, queued for the next release and 4.14.x. -corey > > diff --git a/drivers/char/ipmi/ipmi_dmi.c b/drivers/char/ipmi/ipmi_dmi.c > index ab78b3b..c5112b1 100644 > --- a/drivers/char/ipmi/ipmi_dmi.c > +++ b/drivers/char/ipmi/ipmi_dmi.c > @@ -106,7 +106,10 @@ static void __init dmi_add_platform_ipmi(unsigned long base_addr, > pr_err("ipmi:dmi: Error allocation IPMI platform device\n"); > return; > } > - pdev->driver_override = override; > + pdev->driver_override = kasprintf(GFP_KERNEL, "%s", > + override); > + if (!pdev->driver_override) > + goto err; > > if (type == IPMI_DMI_TYPE_SSIF) { > set_prop_entry(p[pidx++], "i2c-addr", u16, base_addr); > diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c > index 779869e..2a19aa8 100644 > --- a/drivers/char/ipmi/ipmi_si_intf.c > +++ b/drivers/char/ipmi/ipmi_si_intf.c > @@ -2426,6 +2426,7 @@ int ipmi_si_remove_by_dev(struct device *dev) > { > struct smi_info *e; > int rv = -ENOENT; > + struct platform_device *pdev = to_platform_device(dev); > > mutex_lock(&smi_infos_lock); > list_for_each_entry(e, &smi_infos, link) { > @@ -2436,6 +2437,7 @@ int ipmi_si_remove_by_dev(struct device *dev) > } > } > mutex_unlock(&smi_infos_lock); > + kfree(pdev->driver_override); > > return rv; > }