tjh.dev/kernel at 5e89d62ec1014800e411868b8d750f9d631bdd01

The following kernel memory leak was noticed after running
tools/testing/selftests/firmware/fw_run_tests.sh:

[root@pc-mtodorov firmware]# cat /sys/kernel/debug/kmemleak
.
.
.
unreferenced object 0xffff955389bc3400 (size 1024):
comm "test_firmware-0", pid 5451, jiffies 4294944822 (age 65.652s)
hex dump (first 32 bytes):
47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567..........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0
[<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240
[<ffffffff962704de>] kmalloc_trace+0x2e/0xc0
[<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180
[<ffffffff95fd813b>] kthread+0x10b/0x140
[<ffffffff95e033e9>] ret_from_fork+0x29/0x50
unreferenced object 0xffff9553c334b400 (size 1024):
comm "test_firmware-1", pid 5452, jiffies 4294944822 (age 65.652s)
hex dump (first 32 bytes):
47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567..........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0
[<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240
[<ffffffff962704de>] kmalloc_trace+0x2e/0xc0
[<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180
[<ffffffff95fd813b>] kthread+0x10b/0x140
[<ffffffff95e033e9>] ret_from_fork+0x29/0x50
unreferenced object 0xffff9553c334f000 (size 1024):
comm "test_firmware-2", pid 5453, jiffies 4294944822 (age 65.652s)
hex dump (first 32 bytes):
47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567..........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0
[<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240
[<ffffffff962704de>] kmalloc_trace+0x2e/0xc0
[<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180
[<ffffffff95fd813b>] kthread+0x10b/0x140
[<ffffffff95e033e9>] ret_from_fork+0x29/0x50
unreferenced object 0xffff9553c3348400 (size 1024):
comm "test_firmware-3", pid 5454, jiffies 4294944822 (age 65.652s)
hex dump (first 32 bytes):
47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567..........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0
[<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240
[<ffffffff962704de>] kmalloc_trace+0x2e/0xc0
[<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180
[<ffffffff95fd813b>] kthread+0x10b/0x140
[<ffffffff95e033e9>] ret_from_fork+0x29/0x50
[root@pc-mtodorov firmware]#

Note that the size 1024 corresponds to the size of the test firmware
buffer. The actual number of the buffers leaked is around 70-110,
depending on the test run.

The cause of the leak is the following:

request_partial_firmware_into_buf() and request_firmware_into_buf()
provided firmware buffer isn't released on release_firmware(), we
have allocated it and we are responsible for deallocating it manually.
This is introduced in a number of context where previously only
release_firmware() was called, which was insufficient.

Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Fixes: 7feebfa487b92 ("test_firmware: add support for request_firmware_into_buf")
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Russ Weight <russell.h.weight@intel.com>
Cc: Tianfei zhang <tianfei.zhang@intel.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Zhengchao Shao <shaozhengchao@huawei.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Cc: stable@vger.kernel.org # v5.4
Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Link: https://lore.kernel.org/r/20230509084746.48259-3-mirsad.todorovac@alu.unizg.hr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

48e15602

Mirsad Goran Todorovac

2 years ago

media: v4l2-subdev: Fix missing kerneldoc for client_caps

b37a356d

Tomi Valkeinen

2 years ago

Merge tag 'tty-6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

12c2f77b

Linus Torvalds

2 years ago

drivers: base: cacheinfo: Update cpu_map_populated during CPU Hotplug

Until commit 5c2712387d48 ("cacheinfo: Fix LLC is not exported through
sysfs"), cacheinfo called populate_cache_leaves() for CPU coming online
which let the arch specific functions handle (at least on x86)
populating the shared_cpu_map. However, with the changes in the
aforementioned commit, populate_cache_leaves() is not called when a CPU
comes online as a result of hotplug since last_level_cache_is_valid()
returns true as the cacheinfo data is not discarded. The CPU coming
online is not present in shared_cpu_map, however, it will not be added
since the cpu_cacheinfo->cpu_map_populated flag is set (it is set in
populate_cache_leaves() when cacheinfo is first populated for x86)

This can lead to inconsistencies in the shared_cpu_map when an offlined
CPU comes online again. Example below depicts the inconsistency in the
shared_cpu_list in cacheinfo when CPU8 is offlined and onlined again on
a 3rd Generation EPYC processor:

# for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143

# echo 0 > /sys/devices/system/cpu/cpu8/online
# echo 1 > /sys/devices/system/cpu/cpu8/online

# for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8
/sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8
/sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8
/sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8

# cat /sys/devices/system/cpu/cpu136/cache/index0/shared_cpu_list
136

# cat /sys/devices/system/cpu/cpu136/cache/index3/shared_cpu_list
9-15,136-143

Clear the flag when the CPU is removed from shared_cpu_map when
cache_shared_cpu_map_remove() is called during CPU hotplug. This will
allow cache_shared_cpu_map_setup() to add the CPU coming back online in
the shared_cpu_map. Set the flag again when the shared_cpu_map is setup.
Following are results of performing the same test as described above with
the changes:

# for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143

# echo 0 > /sys/devices/system/cpu/cpu8/online
# echo 1 > /sys/devices/system/cpu/cpu8/online

# for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143

# cat /sys/devices/system/cpu/cpu136/cache/index0/shared_cpu_list
8,136

# cat /sys/devices/system/cpu/cpu136/cache/index3/shared_cpu_list
8-15,136-143

Fixes: 5c2712387d48 ("cacheinfo: Fix LLC is not exported through sysfs")
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20230508084115.1157-3-kprateek.nayak@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

c26fabe7

K Prateek Nayak

2 years ago

test_firmware: fix a memory leak with reqs buffer

be37bed7

Mirsad Goran Todorovac

2 years ago

media: staging: media: imx: initialize hs_settle to avoid warning

6970888d

Hans Verkuil

2 years ago

Merge tag 'usb-6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

8b435e40

Linus Torvalds

2 years ago

dt-bindings: serial: 8250_omap: add rs485-rts-active-high

403e97d6

Francesco Dolcini

2 years ago

drivers: base: cacheinfo: Fix shared_cpu_map changes in event of CPU hotplug

While building the shared_cpu_map, check if the cache level and cache
type matches. On certain systems that build the cache topology based on
the instance ID, there are cases where the same ID may repeat across
multiple cache levels, leading inaccurate topology.

In event of CPU offlining, the cache_shared_cpu_map_remove() does not
consider if IDs at same level are being compared. As a result, when same
IDs repeat across different cache levels, the CPU going offline is not
removed from all the shared_cpu_map.

Below is the output of cache topology of CPU8 and it's SMT sibling after
CPU8 is offlined on a dual socket 3rd Generation AMD EPYC processor
(2 x 64C/128T) running kernel release v6.3:

# for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143

# echo 0 > /sys/devices/system/cpu/cpu8/online

# for i in /sys/devices/system/cpu/cpu136/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu136/cache/index0/shared_cpu_list: 136
/sys/devices/system/cpu/cpu136/cache/index1/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu136/cache/index2/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu136/cache/index3/shared_cpu_list: 9-15,136-143

CPU8 is removed from index0 (L1i) but remains in the shared_cpu_list of
index1 (L1d) and index2 (L2). Since L1i, L1d, and L2 are shared by the
SMT siblings, and they have the same cache instance ID, CPU 2 is only
removed from the first index with matching ID which is index1 (L1i) in
this case. With this fix, the results are as expected when performing
the same experiment on the same system:

# for i in /sys/devices/system/cpu/cpu8/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu8/cache/index0/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index1/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index2/shared_cpu_list: 8,136
/sys/devices/system/cpu/cpu8/cache/index3/shared_cpu_list: 8-15,136-143

# echo 0 > /sys/devices/system/cpu/cpu8/online

# for i in /sys/devices/system/cpu/cpu136/cache/index*/shared_cpu_list; do echo -n "$i: "; cat $i; done
/sys/devices/system/cpu/cpu136/cache/index0/shared_cpu_list: 136
/sys/devices/system/cpu/cpu136/cache/index1/shared_cpu_list: 136
/sys/devices/system/cpu/cpu136/cache/index2/shared_cpu_list: 136
/sys/devices/system/cpu/cpu136/cache/index3/shared_cpu_list: 9-15,136-143

When rebuilding topology, the same problem appears as
cache_shared_cpu_map_setup() implements a similar logic. Consider the
same 3rd Generation EPYC processor: CPUs in Core 1, that share the L1
and L2 caches, have L1 and L2 instance ID as 1. For all the CPUs on
the second chiplet, the L3 ID is also 1 leading to grouping on CPUs from
Core 1 (1, 17) and the entire second chiplet (8-15, 24-31) as CPUs
sharing one cache domain. This went undetected since x86 processors
depended on arch specific populate_cache_leaves() method to repopulate
the shared_cpus_map when CPU came back online until kernel release
v6.3-rc5.

Fixes: 198102c9103f ("cacheinfo: Fix shared_cpu_map to handle shared caches at different levels")
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20230508084115.1157-2-kprateek.nayak@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

126310c9

K Prateek Nayak

2 years ago

test_firmware: prevent race conditions by a correct implementation of locking

Dan Carpenter spotted a race condition in a couple of situations like
these in the test_firmware driver:

static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
{
u8 val;
int ret;

ret = kstrtou8(buf, 10, &val);
if (ret)
return ret;

mutex_lock(&test_fw_mutex);
*(u8 *)cfg = val;
mutex_unlock(&test_fw_mutex);

/* Always return full write size even if we didn't consume all */
return size;
}

static ssize_t config_num_requests_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int rc;

mutex_lock(&test_fw_mutex);
if (test_fw_config->reqs) {
pr_err("Must call release_all_firmware prior to changing config\n");
rc = -EINVAL;
mutex_unlock(&test_fw_mutex);
goto out;
}
mutex_unlock(&test_fw_mutex);

rc = test_dev_config_update_u8(buf, count,
&test_fw_config->num_requests);

out:
return rc;
}

static ssize_t config_read_fw_idx_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
return test_dev_config_update_u8(buf, count,
&test_fw_config->read_fw_idx);
}

The function test_dev_config_update_u8() is called from both the locked
and the unlocked context, function config_num_requests_store() and
config_read_fw_idx_store() which can both be called asynchronously as
they are driver's methods, while test_dev_config_update_u8() and siblings
change their argument pointed to by u8 *cfg or similar pointer.

To avoid deadlock on test_fw_mutex, the lock is dropped before calling
test_dev_config_update_u8() and re-acquired within test_dev_config_update_u8()
itself, but alas this creates a race condition.

Having two locks wouldn't assure a race-proof mutual exclusion.

This situation is best avoided by the introduction of a new, unlocked
function __test_dev_config_update_u8() which can be called from the locked
context and reducing test_dev_config_update_u8() to:

static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
{
int ret;

mutex_lock(&test_fw_mutex);
ret = __test_dev_config_update_u8(buf, size, cfg);
mutex_unlock(&test_fw_mutex);

return ret;
}

doing the locking and calling the unlocked primitive, which enables both
locked and unlocked versions without duplication of code.

The similar approach was applied to all functions called from the locked
and the unlocked context, which safely mitigates both deadlocks and race
conditions in the driver.

__test_dev_config_update_bool(), __test_dev_config_update_u8() and
__test_dev_config_update_size_t() unlocked versions of the functions
were introduced to be called from the locked contexts as a workaround
without releasing the main driver's lock and thereof causing a race
condition.

The test_dev_config_update_bool(), test_dev_config_update_u8() and
test_dev_config_update_size_t() locked versions of the functions
are being called from driver methods without the unnecessary multiplying
of the locking and unlocking code for each method, and complicating
the code with saving of the return value across lock.

Fixes: 7feebfa487b92 ("test_firmware: add support for request_firmware_into_buf")
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russ Weight <russell.h.weight@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Tianfei Zhang <tianfei.zhang@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-kselftest@vger.kernel.org
Cc: stable@vger.kernel.org # v5.4
Suggested-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Link: https://lore.kernel.org/r/20230509084746.48259-1-mirsad.todorovac@alu.unizg.hr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4acfe3df

Mirsad Goran Todorovac

2 years ago

media: v4l2-mc: Drop subdev check in v4l2_create_fwnode_links_to_pad()

3a4cdef1

Vaishnav Achath

2 years ago

branches 3

master 18 hours ago default

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tags 928

v7.1-rc1

1 day ago latest

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.

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