When I register a kset in the following way:
static struct kset my_kset;
kobject_set_name(&my_kset.kobj, "my_kset");
ret = kset_register(&my_kset);
A null pointer dereference exception is occurred:
[ 4453.568337] Unable to handle kernel NULL pointer dereference at \
virtual address 0000000000000028
... ...
[ 4453.810361] Call trace:
[ 4453.813062] kobject_get_ownership+0xc/0x34
[ 4453.817493] kobject_add_internal+0x98/0x274
[ 4453.822005] kset_register+0x5c/0xb4
[ 4453.825820] my_kobj_init+0x44/0x1000 [my_kset]
... ...
Because I didn't initialize my_kset.kobj.ktype.
According to the description in Documentation/core-api/kobject.rst:
- A ktype is the type of object that embeds a kobject. Every structure
that embeds a kobject needs a corresponding ktype.
So add sanity check to make sure kset->kobj.ktype is not NULL.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20230805084114.1298-2-thunder.leizhen@huaweicloud.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without an explicit level the stacktraces are printed at a default
level.
If this level does not match the one from the logging level it may
happen that the stacktrace is shown without the message or vice versa.
Both these cases are confusing, so make sure the user always sees both,
the message and the stacktrace.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230311-kobject-warning-v1-2-1ebba4f71fb5@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In kobject_get_path(), if kobj->name is changed between calls
get_kobj_path_length() and fill_kobj_path() and the length becomes
longer, then fill_kobj_path() will have an out-of-bounds bug.
The actual current problem occurs when the ixgbe probe.
In ixgbe_mii_bus_init(), if the length of netdev->dev.kobj.name
length becomes longer, out-of-bounds will occur.
cpu0 cpu1
ixgbe_probe
register_netdev(netdev)
netdev_register_kobject
device_add
kobject_uevent // Sending ADD events
systemd-udevd // rename netdev
dev_change_name
device_rename
kobject_rename
ixgbe_mii_bus_init |
mdiobus_register |
__mdiobus_register |
device_register |
device_add |
kobject_uevent |
kobject_get_path |
len = get_kobj_path_length // old name |
path = kzalloc(len, gfp_mask); |
kobj->name = name;
/* name length becomes
* longer
*/
fill_kobj_path /* kobj path length is
* longer than path,
* resulting in out of
* bounds when filling path
*/
This is the kasan report:
==================================================================
BUG: KASAN: slab-out-of-bounds in fill_kobj_path+0x50/0xc0
Write of size 7 at addr ff1100090573d1fd by task kworker/28:1/673
Workqueue: events work_for_cpu_fn
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x48
print_address_description.constprop.0+0x86/0x1e7
print_report+0x36/0x4f
kasan_report+0xad/0x130
kasan_check_range+0x35/0x1c0
memcpy+0x39/0x60
fill_kobj_path+0x50/0xc0
kobject_get_path+0x5a/0xc0
kobject_uevent_env+0x140/0x460
device_add+0x5c7/0x910
__mdiobus_register+0x14e/0x490
ixgbe_probe.cold+0x441/0x574 [ixgbe]
local_pci_probe+0x78/0xc0
work_for_cpu_fn+0x26/0x40
process_one_work+0x3b6/0x6a0
worker_thread+0x368/0x520
kthread+0x165/0x1a0
ret_from_fork+0x1f/0x30
This reproducer triggers that bug:
while:
do
rmmod ixgbe
sleep 0.5
modprobe ixgbe
sleep 0.5
When calling fill_kobj_path() to fill path, if the name length of
kobj becomes longer, return failure and retry. This fixes the problem.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Link: https://lore.kernel.org/r/20221220012143.52141-1-wanghai38@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull driver core updates from Greg KH:
"Here is the set of driver core and kernfs changes for 6.2-rc1.
The "big" change in here is the addition of a new macro,
container_of_const() that will preserve the "const-ness" of a pointer
passed into it.
The "problem" of the current container_of() macro is that if you pass
in a "const *", out of it can comes a non-const pointer unless you
specifically ask for it. For many usages, we want to preserve the
"const" attribute by using the same call. For a specific example, this
series changes the kobj_to_dev() macro to use it, allowing it to be
used no matter what the const value is. This prevents every subsystem
from having to declare 2 different individual macros (i.e.
kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
the const value at build time, which having 2 macros would not do
either.
The driver for all of this have been discussions with the Rust kernel
developers as to how to properly mark driver core, and kobject,
objects as being "non-mutable". The changes to the kobject and driver
core in this pull request are the result of that, as there are lots of
paths where kobjects and device pointers are not modified at all, so
marking them as "const" allows the compiler to enforce this.
So, a nice side affect of the Rust development effort has been already
to clean up the driver core code to be more obvious about object
rules.
All of this has been bike-shedded in quite a lot of detail on lkml
with different names and implementations resulting in the tiny version
we have in here, much better than my original proposal. Lots of
subsystem maintainers have acked the changes as well.
Other than this change, included in here are smaller stuff like:
- kernfs fixes and updates to handle lock contention better
- vmlinux.lds.h fixes and updates
- sysfs and debugfs documentation updates
- device property updates
All of these have been in the linux-next tree for quite a while with
no problems"
* tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits)
device property: Fix documentation for fwnode_get_next_parent()
firmware_loader: fix up to_fw_sysfs() to preserve const
usb.h: take advantage of container_of_const()
device.h: move kobj_to_dev() to use container_of_const()
container_of: add container_of_const() that preserves const-ness of the pointer
driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion.
driver core: fix up missed scsi/cxlflash class.devnode() conversion.
driver core: fix up some missing class.devnode() conversions.
driver core: make struct class.devnode() take a const *
driver core: make struct class.dev_uevent() take a const *
cacheinfo: Remove of_node_put() for fw_token
device property: Add a blank line in Kconfig of tests
device property: Rename goto label to be more precise
device property: Move PROPERTY_ENTRY_BOOL() a bit down
device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*()
kernfs: fix all kernel-doc warnings and multiple typos
driver core: pass a const * into of_device_uevent()
kobject: kset_uevent_ops: make name() callback take a const *
kobject: kset_uevent_ops: make filter() callback take a const *
kobject: make kobject_namespace take a const *
...
Inject fault while loading module, kset_register() may fail.
If it fails, the kset.kobj.name allocated by kobject_set_name()
which must be called before a call to kset_register() may be
leaked, since refcount of kobj was set in kset_init().
To mitigate this, we free the name in kset_register() when an
error is encountered, i.e. when kset_register() returns an error.
A kset may be embedded in a larger structure which may be dynamically
allocated in callers, it needs to be freed in ktype.release() or error
path in callers, in this case, we can not call kset_put() in kset_register(),
or it will cause double free, so just call kfree_const() to free the
name and set it to NULL to avoid accessing bad pointer in callers.
With this fix, the callers don't need care about freeing the name
and may call kset_put() if kset_register() fails.
Suggested-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: <luben.tuikov@amd.com>
Link: https://lore.kernel.org/r/20221025071549.1280528-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Now that all in-kernel users of default_attrs for the kobj_type are gone
and converted to properly use the default_groups pointer instead, it can
be safely removed.
There is one standard way to create sysfs files in a kobj_type, and not
two like before, causing confusion as to which should be used.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20220106133151.607703-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function kobject_create() is only used by one caller,
kobject_create_and_add(), no other driver uses it, nor is exported to
other modules.
However it's still exported in kobject.h, and can sometimes confuse
users of kobject.h.
Since all users should call kobject_create_and_add(), or if extra
attributes are needed, should alloc the memory manually then call
kobject_init_and_add().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Link: https://lore.kernel.org/r/20210831093044.110729-1-wqu@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If kobject_del() is invoked by kobject_cleanup() to delete the
target kobject, it may cause its parent kobject to be freed
before invoking the target kobject's ->release() method, which
effectively means freeing the parent before dealing with the
child entirely.
That is confusing at best and it may also lead to functional
issues if the callers of kobject_cleanup() are not careful enough
about the order in which these calls are made, so avoid the
problem by making kobject_cleanup() drop the last reference to
the target kobject's parent at the end, after invoking the target
kobject's ->release() method.
[ rjw: Rewrite the subject and changelog, make kobject_cleanup()
drop the parent reference only when __kobject_del() has been
called. ]
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Fixes: 7589238a8c ("Revert "software node: Simplify software_node_release() function"")
Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/1908555.IiAGLGrh1Z@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull driver core updates from Greg KH:
"Here is the set of driver core patches for 5.8-rc1.
Not all that huge this release, just a number of small fixes and
updates:
- software node fixes
- kobject now sends KOBJ_REMOVE when it is removed from sysfs, not
when it is removed from memory (which could come much later)
- device link additions and fixes based on testing on more devices
- firmware core cleanups
- other minor changes, full details in the shortlog
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits)
driver core: Update device link status correctly for SYNC_STATE_ONLY links
firmware_loader: change enum fw_opt to u32
software node: implement software_node_unregister()
kobject: send KOBJ_REMOVE uevent when the object is removed from sysfs
driver core: Remove unnecessary is_fwnode_dev variable in device_add()
drivers property: When no children in primary, try secondary
driver core: platform: Fix spelling errors in platform.c
driver core: Remove check in driver_deferred_probe_force_trigger()
of: platform: Batch fwnode parsing when adding all top level devices
driver core: fw_devlink: Add support for batching fwnode parsing
driver core: Look for waiting consumers only for a fwnode's primary device
driver core: Move code to the right part of the file
Revert "Revert "driver core: Set fw_devlink to "permissive" behavior by default""
drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish
firmware_loader: move fw_fallback_config to a private kernel symbol namespace
driver core: Add missing '\n' in log messages
driver/base/soc: Use kobj_to_dev() API
Add documentation on meaning of -EPROBE_DEFER
driver core: platform: remove redundant assignment to variable ret
debugfs: Use the correct style for SPDX License Identifier
...
It is possible for a KOBJ_REMOVE uevent to be sent to userspace way
after the files are actually gone from sysfs, due to how reference
counting for kobjects work. This should not be a problem, but it would
be good to properly send the information when things are going away, not
at some later point in time in the future.
Before this move, if a kobject's parent was torn down before the child,
when the call to kobject_uevent() happened, the parent walk to try to
reconstruct the full path of the kobject could be a total mess and cause
crashes. It's not good to try to tear down a kobject tree from top
down, but let's at least try to not to crash if a user does so.
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200524153041.2361-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
