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Guenter Roeck 1957de95d4 usb: typec: tcpm: Add NULL check before dereferencing config
When instantiating tcpm on an NXP OM 13588 board with NXP PTN5110,
the following crash is seen when writing into the 'preferred_role'
sysfs attribute.

Unable to handle kernel NULL pointer dereference at virtual address 00000028
pgd = f69149ad
[00000028] *pgd=00000000
Internal error: Oops: 5 [#1] THUMB2
Modules linked in: tcpci tcpm
CPU: 0 PID: 1882 Comm: bash Not tainted 5.1.18-sama5-armv7-r2 #4
Hardware name: Atmel SAMA5
PC is at tcpm_try_role+0x3a/0x4c [tcpm]
LR is at tcpm_try_role+0x15/0x4c [tcpm]
pc : [<bf8000e2>]    lr : [<bf8000bd>]    psr: 60030033
sp : dc1a1e88  ip : c03fb47d  fp : 00000000
r10: dc216190  r9 : dc1a1f78  r8 : 00000001
r7 : df4ae044  r6 : dd032e90  r5 : dd1ce340  r4 : df4ae054
r3 : 00000000  r2 : 00000000  r1 : 00000000  r0 : df4ae044
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment none
Control: 50c53c7d  Table: 3efec059  DAC: 00000051
Process bash (pid: 1882, stack limit = 0x6a6d4aa5)
Stack: (0xdc1a1e88 to 0xdc1a2000)
1e80:                   dd05d808 dd1ce340 00000001 00000007 dd1ce340 c03fb4a7
1ea0: 00000007 00000007 dc216180 00000000 00000000 c01e1e03 00000000 00000000
1ec0: c0907008 dee98b40 c01e1d5d c06106c4 00000000 00000000 00000007 c0194e8b
1ee0: 0000000a 00000400 00000000 c01a97db dc22bf00 ffffe000 df4b6a00 df745900
1f00: 00000001 00000001 000000dd c01a9c2f 7aeab3be c0907008 00000000 dc22bf00
1f20: c0907008 00000000 00000000 00000000 00000000 7aeab3be 00000007 dee98b40
1f40: 005dc318 dc1a1f78 00000000 00000000 00000007 c01969f7 0000000a c01a20cb
1f60: dee98b40 c0907008 dee98b40 005dc318 00000000 c0196b9b 00000000 00000000
1f80: dee98b40 7aeab3be 00000074 005dc318 b6f3bdb0 00000004 c0101224 dc1a0000
1fa0: 00000004 c0101001 00000074 005dc318 00000001 005dc318 00000007 00000000
1fc0: 00000074 005dc318 b6f3bdb0 00000004 00000007 00000007 00000000 00000000
1fe0: 00000004 be800880 b6ed35b3 b6e5c746 60030030 00000001 00000000 00000000
[<bf8000e2>] (tcpm_try_role [tcpm]) from [<c03fb4a7>] (preferred_role_store+0x2b/0x5c)
[<c03fb4a7>] (preferred_role_store) from [<c01e1e03>] (kernfs_fop_write+0xa7/0x150)
[<c01e1e03>] (kernfs_fop_write) from [<c0194e8b>] (__vfs_write+0x1f/0x104)
[<c0194e8b>] (__vfs_write) from [<c01969f7>] (vfs_write+0x6b/0x104)
[<c01969f7>] (vfs_write) from [<c0196b9b>] (ksys_write+0x43/0x94)
[<c0196b9b>] (ksys_write) from [<c0101001>] (ret_fast_syscall+0x1/0x62)

Since commit 96232cbc6c ("usb: typec: tcpm: support get typec and pd
config from device properties"), the 'config' pointer in struct tcpc_dev
is optional when registering a Type-C port. Since it is optional, we have
to check if it is NULL before dereferencing it.

Reported-by: Douglas Gilbert <dgilbert@interlog.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Fixes: 96232cbc6c ("usb: typec: tcpm: support get typec and pd config from device properties")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Jun Li <jun.li@nxp.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/1563979112-22483-1-git-send-email-linux@roeck-us.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 11:04:09 +02:00
Documentation USB fixes for 5.3-rc2 2019-07-28 09:52:35 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch SPDX fixes for 5.3-rc2 2019-07-28 10:00:06 -07:00
block for-linus-20190726-2 2019-07-26 19:20:34 -07:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto USB / PHY patches for 5.3-rc1 2019-07-11 15:40:06 -07:00
drivers usb: typec: tcpm: Add NULL check before dereferencing config 2019-07-30 11:04:09 +02:00
fs SPDX fixes for 5.3-rc2 2019-07-28 10:00:06 -07:00
include TTY fixes for 5.3-rc2 2019-07-28 10:18:33 -07:00
init Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
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lib test_firmware: fix a memory leak bug 2019-07-25 14:39:52 +02:00
mm mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() 2019-07-22 10:18:30 +02:00
net tcp: be more careful in tcp_fragment() 2019-07-21 20:41:24 -07:00
samples treewide: remove SPDX "WITH Linux-syscall-note" from kernel-space headers again 2019-07-25 11:05:10 +02:00
scripts Kbuild fixes for v5.3 2019-07-28 10:35:04 -07:00
security meminit fix 2019-07-28 12:33:15 -07:00
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usr kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test 2019-07-23 10:45:46 +02:00
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CREDITS Remove references to dead website. 2019-07-19 12:22:04 -07:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Char/Misc driver fixes for 5.3-rc2 2019-07-28 10:26:10 -07:00
Makefile Linux 5.3-rc2 2019-07-28 12:47:02 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.