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Wed, 06 Feb 2019 10:53:08 -0800 (PST) Date: Wed, 6 Feb 2019 10:53:07 -0800 From: Dmitry Torokhov To: =?utf-8?B?UGF3ZcWC?= Chmiel Cc: robh+dt@kernel.org, mark.rutland@arm.com, xc-racer2@live.ca, devicetree@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 5/5] input: misc: bma150: Register input device after setting private data Message-ID: <20190206185307.GD174258@dtor-ws> References: <20190202151806.9064-1-pawel.mikolaj.chmiel@gmail.com> <20190202151806.9064-6-pawel.mikolaj.chmiel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190202151806.9064-6-pawel.mikolaj.chmiel@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 02, 2019 at 04:18:06PM +0100, Paweł Chmiel wrote: > From: Jonathan Bakker > > Otherwise we introduce a race condition where userspace can request input > before we're ready leading to null pointer dereference such as > > input: bma150 as /devices/platform/i2c-gpio-2/i2c-5/5-0038/input/input3 > Unable to handle kernel NULL pointer dereference at virtual address 00000018 > pgd = (ptrval) > [00000018] *pgd=55dac831, *pte=00000000, *ppte=00000000 > Internal error: Oops: 17 [#1] PREEMPT ARM > Modules linked in: bma150 input_polldev [last unloaded: bma150] > CPU: 0 PID: 2870 Comm: accelerometer Not tainted 5.0.0-rc3-dirty #46 > Hardware name: Samsung S5PC110/S5PV210-based board > PC is at input_event+0x8/0x60 > LR is at bma150_report_xyz+0x9c/0xe0 [bma150] > pc : [<80450f70>] lr : [<7f0a614c>] psr: 800d0013 > sp : a4c1fd78 ip : 00000081 fp : 00020000 > r10: 00000000 r9 : a5e2944c r8 : a7455000 > r7 : 00000016 r6 : 00000101 r5 : a7617940 r4 : 80909048 > r3 : fffffff2 r2 : 00000000 r1 : 00000003 r0 : 00000000 > Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none > Control: 10c5387d Table: 54e34019 DAC: 00000051 > Process accelerometer (pid: 2870, stack limit = 0x(ptrval)) > Stackck: (0xa4c1fd78 to 0xa4c20000) > fd60: fffffff3 fc813f6c > fd80: 40410581 d7530ce3 a5e2817c a7617f00 a5e29404 a5e2817c 00000000 7f008324 > fda0: a5e28000 8044f59c a5fdd9d0 a5e2945c a46a4a00 a5e29668 a7455000 80454f10 > fdc0: 80909048 a5e29668 a5fdd9d0 a46a4a00 806316d0 00000000 a46a4a00 801df5f0 > fde0: 00000000 d7530ce3 a4c1fec0 a46a4a00 00000000 a5fdd9d0 a46a4a08 801df53c > fe00: 00000000 801d74bc a4c1fec0 00000000 a4c1ff70 00000000 a7038da8 00000000 > fe20: a46a4a00 801e91fc a411bbe0 801f2e88 00000004 00000000 80909048 00000041 > fe40: 00000000 00020000 00000000 dead4ead a6a88da0 00000000 ffffe000 806fcae8 > fe60: a4c1fec8 00000000 80909048 00000002 a5fdd9d0 a7660110 a411bab0 00000001 > fe80: dead4ead ffffffff ffffffff a4c1fe8c a4c1fe8c d7530ce3 20000013 80909048 > fea0: 80909048 a4c1ff70 00000001 fffff000 a4c1e000 00000005 00026038 801eabd8 > fec0: a7660110 a411bab0 b9394901 00000006 a696201b 76fb3000 00000000 a7039720 > fee0: a5fdd9d0 00000101 00000002 00000096 00000000 00000000 00000000 a4c1ff00 > ff00: a6b310f4 805cb174 a6b310f4 00000010 00000fe0 00000010 a4c1e000 d7530ce3 > ff20: 00000003 a5f41400 a5f41424 00000000 a6962000 00000000 00000003 00000002 > ff40: ffffff9c 000a0000 80909048 d7530ce3 a6962000 00000003 80909048 ffffff9c > ff60: a6962000 801d890c 00000000 00000000 00020000 a7590000 00000004 00000100 > ff80: 00000001 d7530ce3 000288b8 00026320 000288b8 00000005 80101204 a4c1e000 > ffa0: 00000005 80101000 000288b8 00026320 000288b8 000a0000 00000000 00000000 > ffc0: 000288b8 00026320 000288b8 00000005 7eef3bac 000264e8 00028ad8 00026038 > ffe0: 00000005 7eef3300 76f76e91 76f78546 800d0030 000288b8 00000000 00000000 > [<80450f70>] (input_event) from [] (0xa5e2817c) > Code: e1a08148 eaffffa8 e351001f 812fff1e (e590c018) > ---[ end trace 1c691ee85f2ff243 ]--- > > Signed-off-by: Jonathan Bakker > Signed-off-by: Paweł Chmiel Applied, thank you. > --- > drivers/input/misc/bma150.c | 15 +++------------ > 1 file changed, 3 insertions(+), 12 deletions(-) > > diff --git a/drivers/input/misc/bma150.c b/drivers/input/misc/bma150.c > index 1cdc8ce97968..64caf43e5bca 100644 > --- a/drivers/input/misc/bma150.c > +++ b/drivers/input/misc/bma150.c > @@ -470,7 +470,6 @@ static void bma150_init_input_device(struct bma150_data *bma150, > static int bma150_register_input_device(struct bma150_data *bma150) > { > struct input_dev *idev; > - int error; > > idev = devm_input_allocate_device(&bma150->client->dev); > if (!idev) > @@ -482,18 +481,14 @@ static int bma150_register_input_device(struct bma150_data *bma150) > idev->close = bma150_irq_close; > input_set_drvdata(idev, bma150); > > - error = input_register_device(idev); > - if (error) > - return error; > - > bma150->input = idev; > - return 0; > + > + return input_register_device(idev); > } > > static int bma150_register_polled_device(struct bma150_data *bma150) > { > struct input_polled_dev *ipoll_dev; > - int error; > > ipoll_dev = devm_input_allocate_polled_device(&bma150->client->dev); > if (!ipoll_dev) > @@ -509,14 +504,10 @@ static int bma150_register_polled_device(struct bma150_data *bma150) > > bma150_init_input_device(bma150, ipoll_dev->input); > > - error = input_register_polled_device(ipoll_dev); > - if (error) > - return error; > - > bma150->input_polled = ipoll_dev; > bma150->input = ipoll_dev->input; > > - return 0; > + return input_register_polled_device(ipoll_dev); > } > > int bma150_cfg_from_of(struct device_node *np) > -- > 2.17.1 > -- Dmitry