bde50d13e4
commit 90cc55f067f6ca0e64e5e52883ece47d8af7b67b upstream. 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 [<a5e2817c>] (0xa5e2817c) Code: e1a08148 eaffffa8 e351001f 812fff1e (e590c018) ---[ end trace 1c691ee85f2ff243 ]--- Signed-off-by: Jonathan Bakker <xc-racer2@live.ca> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.