<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/drivers/i2c/i2c-dev.c, branch v5.7</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v5.7</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v5.7'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2020-03-20T17:34:29Z</updated>
<entry>
<title>i2c: dev: Fix the race between the release of i2c_dev and cdev</title>
<updated>2020-03-20T17:34:29Z</updated>
<author>
<name>Kevin Hao</name>
<email>haokexin@gmail.com</email>
</author>
<published>2019-10-11T15:00:14Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=1413ef638abae4ab5621901cf4d8ef08a4a48ba6'/>
<id>urn:sha1:1413ef638abae4ab5621901cf4d8ef08a4a48ba6</id>
<content type='text'>
The struct cdev is embedded in the struct i2c_dev. In the current code,
we would free the i2c_dev struct directly in put_i2c_dev(), but the
cdev is manged by a kobject, and the release of it is not predictable.
So it is very possible that the i2c_dev is freed before the cdev is
entirely released. We can easily get the following call trace with
CONFIG_DEBUG_KOBJECT_RELEASE and CONFIG_DEBUG_OBJECTS_TIMERS enabled.
  ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x38
  WARNING: CPU: 19 PID: 1 at lib/debugobjects.c:325 debug_print_object+0xb0/0xf0
  Modules linked in:
  CPU: 19 PID: 1 Comm: swapper/0 Tainted: G        W         5.2.20-yocto-standard+ #120
  Hardware name: Marvell OcteonTX CN96XX board (DT)
  pstate: 80c00089 (Nzcv daIf +PAN +UAO)
  pc : debug_print_object+0xb0/0xf0
  lr : debug_print_object+0xb0/0xf0
  sp : ffff00001292f7d0
  x29: ffff00001292f7d0 x28: ffff800b82151788
  x27: 0000000000000001 x26: ffff800b892c0000
  x25: ffff0000124a2558 x24: 0000000000000000
  x23: ffff00001107a1d8 x22: ffff0000116b5088
  x21: ffff800bdc6afca8 x20: ffff000012471ae8
  x19: ffff00001168f2c8 x18: 0000000000000010
  x17: 00000000fd6f304b x16: 00000000ee79de43
  x15: ffff800bc0e80568 x14: 79616c6564203a74
  x13: 6e6968207473696c x12: 5f72656d6974203a
  x11: ffff0000113f0018 x10: 0000000000000000
  x9 : 000000000000001f x8 : 0000000000000000
  x7 : ffff0000101294cc x6 : 0000000000000000
  x5 : 0000000000000000 x4 : 0000000000000001
  x3 : 00000000ffffffff x2 : 0000000000000000
  x1 : 387fc15c8ec0f200 x0 : 0000000000000000
  Call trace:
   debug_print_object+0xb0/0xf0
   __debug_check_no_obj_freed+0x19c/0x228
   debug_check_no_obj_freed+0x1c/0x28
   kfree+0x250/0x440
   put_i2c_dev+0x68/0x78
   i2cdev_detach_adapter+0x60/0xc8
   i2cdev_notifier_call+0x3c/0x70
   notifier_call_chain+0x8c/0xe8
   blocking_notifier_call_chain+0x64/0x88
   device_del+0x74/0x380
   device_unregister+0x54/0x78
   i2c_del_adapter+0x278/0x2d0
   unittest_i2c_bus_remove+0x3c/0x80
   platform_drv_remove+0x30/0x50
   device_release_driver_internal+0xf4/0x1c0
   driver_detach+0x58/0xa0
   bus_remove_driver+0x84/0xd8
   driver_unregister+0x34/0x60
   platform_driver_unregister+0x20/0x30
   of_unittest_overlay+0x8d4/0xbe0
   of_unittest+0xae8/0xb3c
   do_one_initcall+0xac/0x450
   do_initcall_level+0x208/0x224
   kernel_init_freeable+0x2d8/0x36c
   kernel_init+0x18/0x108
   ret_from_fork+0x10/0x1c
  irq event stamp: 3934661
  hardirqs last  enabled at (3934661): [&lt;ffff00001009fa04&gt;] debug_exception_exit+0x4c/0x58
  hardirqs last disabled at (3934660): [&lt;ffff00001009fb14&gt;] debug_exception_enter+0xa4/0xe0
  softirqs last  enabled at (3934654): [&lt;ffff000010081d94&gt;] __do_softirq+0x46c/0x628
  softirqs last disabled at (3934649): [&lt;ffff0000100b4a1c&gt;] irq_exit+0x104/0x118

This is a common issue when using cdev embedded in a struct.
Fortunately, we already have a mechanism to solve this kind of issue.
Please see commit 233ed09d7fda ("chardev: add helper function to
register char devs with a struct device") for more detail.

In this patch, we choose to embed the struct device into the i2c_dev,
and use the API provided by the commit 233ed09d7fda to make sure that
the release of i2c_dev and cdev are in sequence.

Signed-off-by: Kevin Hao &lt;haokexin@gmail.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
</entry>
<entry>
<title>i2c: dev: keep sorting of includes</title>
<updated>2020-02-26T10:06:43Z</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa@the-dreams.de</email>
</author>
<published>2020-01-30T20:23:12Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=f01adfabbfc4a62a9750cae3abcdf848029ee300'/>
<id>urn:sha1:f01adfabbfc4a62a9750cae3abcdf848029ee300</id>
<content type='text'>
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
</entry>
<entry>
<title>Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux</title>
<updated>2019-06-02T17:18:11Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-06-02T17:18:11Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=38baf0bb79f51b4fcbf6df8fd181441d7b5c7913'/>
<id>urn:sha1:38baf0bb79f51b4fcbf6df8fd181441d7b5c7913</id>
<content type='text'>
Pull i2c fixes from Wolfram Sang:
 "A memleak fix for the core, two driver bugfixes, as well as fixing
  missing file patterns to MAINTAINERS"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  MAINTAINERS: add I2C DT bindings to ARM platforms
  MAINTAINERS: add DT bindings to i2c drivers
  i2c: synquacer: fix synquacer_i2c_doxfer() return value
  i2c: mlxcpld: Fix wrong initialization order in probe
  i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157</title>
<updated>2019-05-30T18:26:37Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-05-27T06:55:06Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=c942fddf8793b2013be8c901b47d0a8dc02bf99f'/>
<id>urn:sha1:c942fddf8793b2013be8c901b47d0a8dc02bf99f</id>
<content type='text'>
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Richard Fontana &lt;rfontana@redhat.com&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr</title>
<updated>2019-05-27T19:24:43Z</updated>
<author>
<name>Yingjoe Chen</name>
<email>yingjoe.chen@mediatek.com</email>
</author>
<published>2019-05-07T14:20:32Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=a0692f0eef91354b62c2b4c94954536536be5425'/>
<id>urn:sha1:a0692f0eef91354b62c2b4c94954536536be5425</id>
<content type='text'>
If I2C_M_RECV_LEN check failed, msgs[i].buf allocated by memdup_user
will not be freed. Pump index up so it will be freed.

Fixes: 838bfa6049fb ("i2c-dev: Add support for I2C_M_RECV_LEN")
Signed-off-by: Yingjoe Chen &lt;yingjoe.chen@mediatek.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
</entry>
<entry>
<title>i2c: expand minor range when registering chrdev region</title>
<updated>2019-02-15T08:53:34Z</updated>
<author>
<name>Chengguang Xu</name>
<email>cgxu519@gmx.com</email>
</author>
<published>2019-02-12T06:06:57Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=8a6d508a8055ea2ef8477e649662287e57727f54'/>
<id>urn:sha1:8a6d508a8055ea2ef8477e649662287e57727f54</id>
<content type='text'>
Actually, total amount of available minor number for a single major is
MINORMASK + 1. So expand minor range when registering chrdev region.

Signed-off-by: Chengguang Xu &lt;cgxu519@gmx.com&gt;
[wsa: fixed typo in commit message]
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
</entry>
<entry>
<title>i2c: dev: prevent adapter retries and timeout being set as minus value</title>
<updated>2019-01-10T23:14:55Z</updated>
<author>
<name>Yi Zeng</name>
<email>yizeng@asrmicro.com</email>
</author>
<published>2019-01-09T07:33:07Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=6ebec961d59bccf65d08b13fc1ad4e6272a89338'/>
<id>urn:sha1:6ebec961d59bccf65d08b13fc1ad4e6272a89338</id>
<content type='text'>
If adapter-&gt;retries is set to a minus value from user space via ioctl,
it will make __i2c_transfer and __i2c_smbus_xfer skip the calling to
adapter-&gt;algo-&gt;master_xfer and adapter-&gt;algo-&gt;smbus_xfer that is
registered by the underlying bus drivers, and return value 0 to all the
callers. The bus driver will never be accessed anymore by all users,
besides, the users may still get successful return value without any
error or information log print out.

If adapter-&gt;timeout is set to minus value from user space via ioctl,
it will make the retrying loop in __i2c_transfer and __i2c_smbus_xfer
always break after the the first try, due to the time_after always
returns true.

Signed-off-by: Yi Zeng &lt;yizeng@asrmicro.com&gt;
[wsa: minor grammar updates to commit message]
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Cc: stable@kernel.org
</content>
</entry>
<entry>
<title>treewide: kmalloc() -&gt; kmalloc_array()</title>
<updated>2018-06-12T23:19:22Z</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2018-06-12T20:55:00Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=6da2ec56059c3c7a7e5f729e6349e74ace1e5c57'/>
<id>urn:sha1:6da2ec56059c3c7a7e5f729e6349e74ace1e5c57</id>
<content type='text'>
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</content>
</entry>
<entry>
<title>i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr()</title>
<updated>2018-04-27T12:04:10Z</updated>
<author>
<name>Alexander Popov</name>
<email>alex.popov@linux.com</email>
</author>
<published>2018-04-19T12:29:22Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=23a27722b5292ef0b27403c87a109feea8296a5c'/>
<id>urn:sha1:23a27722b5292ef0b27403c87a109feea8296a5c</id>
<content type='text'>
i2cdev_ioctl_rdwr() allocates i2c_msg.buf using memdup_user(), which
returns ZERO_SIZE_PTR if i2c_msg.len is zero.

Currently i2cdev_ioctl_rdwr() always dereferences the buf pointer in case
of I2C_M_RD | I2C_M_RECV_LEN transfer. That causes a kernel oops in
case of zero len.

Let's check the len against zero before dereferencing buf pointer.

This issue was triggered by syzkaller.

Signed-off-by: Alexander Popov &lt;alex.popov@linux.com&gt;
Reviewed-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
[wsa: use '&lt; 1' instead of '!' for easier readability]
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
</entry>
<entry>
<title>i2c: dev: mark RDWR buffers as DMA_SAFE</title>
<updated>2017-12-03T20:19:32Z</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa+renesas@sang-engineering.com</email>
</author>
<published>2017-11-04T20:20:03Z</published>
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<id>urn:sha1:978336d48d887d6deb7793e0d20a4673f357fb8e</id>
<content type='text'>
Reviewed-by: Jonathan Cameron &lt;Jonathan.Cameron@huawei.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
</entry>
</feed>
