of_find_net_device_by_node() searches net devices by their /sys/class/net/,
entry. It is documented in its kernel-doc that:
* If successful, returns a pointer to the net_device with the embedded
* struct device refcount incremented by one, or NULL on failure. The
* refcount must be dropped when done with the net_device.
We are missing a put_device(&conduit->dev) which we could place at the
end of dsa_tree_find_first_conduit(). But to explain why calling
put_device() right away is safe is the same as to explain why the chosen
solution is different.
The code is very poorly split: dsa_tree_find_first_conduit() was first
introduced in commit 95f510d0b7 ("net: dsa: allow the DSA master to be
seen and changed through rtnetlink") but was first used several commits
later, in commit acc43b7bf5 ("net: dsa: allow masters to join a LAG").
Assume there is a switch with 2 CPU ports and 2 conduits, eno2 and eno3.
When we create a LAG (bonding or team device) and place eno2 and eno3
beneath it, we create a 3rd conduit (the LAG device itself), but this is
slightly different than the first two.
Namely, the cpu_dp->conduit pointer of the CPU ports does not change,
and remains pointing towards the physical Ethernet controllers which are
now LAG ports. Only 2 things change:
- the LAG device has a dev->dsa_ptr which marks it as a DSA conduit
- dsa_port_to_conduit(user port) finds the LAG and not the physical
conduit, because of the dp->cpu_port_in_lag bit being set.
When the LAG device is destroyed, dsa_tree_migrate_ports_from_lag_conduit()
is called and this is where dsa_tree_find_first_conduit() kicks in.
This is the logical mistake and the reason why introducing code in one
patch and using it from another is bad practice. I didn't realize that I
don't have to call of_find_net_device_by_node() again; the cpu_dp->conduit
association was never undone, and is still available for direct (re)use.
There's only one concern - maybe the conduit disappeared in the
meantime, but the netdev_hold() call we made during dsa_port_parse_cpu()
(see previous change) ensures that this was not the case.
Therefore, fixing the code means reimplementing it in the simplest way.
I am blaming the time of use, since this is what "git blame" would show
if we were to monitor for the conduit's kobject's refcount remaining
elevated instead of being freed.
Tested on the NXP LS1028A, using the steps from
Documentation/networking/dsa/configuration.rst section "Affinity of user
ports to CPU ports", followed by (extra prints added by me):
$ ip link del bond0
mscc_felix 0000:00:00.5 swp3: Link is Down
bond0 (unregistering): (slave eno2): Releasing backup interface
fsl_enetc 0000:00:00.2 eno2: Link is Down
mscc_felix 0000:00:00.5 swp0: bond0 disappeared, migrating to eno2
mscc_felix 0000:00:00.5 swp1: bond0 disappeared, migrating to eno2
mscc_felix 0000:00:00.5 swp2: bond0 disappeared, migrating to eno2
mscc_felix 0000:00:00.5 swp3: bond0 disappeared, migrating to eno2
Fixes: acc43b7bf5 ("net: dsa: allow masters to join a LAG")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20251215150236.3931670-2-vladimir.oltean@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Problem description
-------------------
DSA has a mumbo-jumbo of reference handling of the conduit net device
and its kobject which, sadly, is just wrong and doesn't make sense.
There are two distinct problems.
1. The OF path, which uses of_find_net_device_by_node(), never releases
the elevated refcount on the conduit's kobject. Nominally, the OF and
non-OF paths should result in objects having identical reference
counts taken, and it is already suspicious that
dsa_dev_to_net_device() has a put_device() call which is missing in
dsa_port_parse_of(), but we can actually even verify that an issue
exists. With CONFIG_DEBUG_KOBJECT_RELEASE=y, if we run this command
"before" and "after" applying this patch:
(unbind the conduit driver for net device eno2)
echo 0000:00:00.2 > /sys/bus/pci/drivers/fsl_enetc/unbind
we see these lines in the output diff which appear only with the patch
applied:
kobject: 'eno2' (ffff002009a3a6b8): kobject_release, parent 0000000000000000 (delayed 1000)
kobject: '109' (ffff0020099d59a0): kobject_release, parent 0000000000000000 (delayed 1000)
2. After we find the conduit interface one way (OF) or another (non-OF),
it can get unregistered at any time, and DSA remains with a long-lived,
but in this case stale, cpu_dp->conduit pointer. Holding the net
device's underlying kobject isn't actually of much help, it just
prevents it from being freed (but we never need that kobject
directly). What helps us to prevent the net device from being
unregistered is the parallel netdev reference mechanism (dev_hold()
and dev_put()).
Actually we actually use that netdev tracker mechanism implicitly on
user ports since commit 2f1e8ea726 ("net: dsa: link interfaces with
the DSA master to get rid of lockdep warnings"), via netdev_upper_dev_link().
But time still passes at DSA switch probe time between the initial
of_find_net_device_by_node() code and the user port creation time, time
during which the conduit could unregister itself and DSA wouldn't know
about it.
So we have to run of_find_net_device_by_node() under rtnl_lock() to
prevent that from happening, and release the lock only with the netdev
tracker having acquired the reference.
Do we need to keep the reference until dsa_unregister_switch() /
dsa_switch_shutdown()?
1: Maybe yes. A switch device will still be registered even if all user
ports failed to probe, see commit 86f8b1c01a ("net: dsa: Do not
make user port errors fatal"), and the cpu_dp->conduit pointers
remain valid. I haven't audited all call paths to see whether they
will actually use the conduit in lack of any user port, but if they
do, it seems safer to not rely on user ports for that reference.
2. Definitely yes. We support changing the conduit which a user port is
associated to, and we can get into a situation where we've moved all
user ports away from a conduit, thus no longer hold any reference to
it via the net device tracker. But we shouldn't let it go nonetheless
- see the next change in relation to dsa_tree_find_first_conduit()
and LAG conduits which disappear.
We have to be prepared to return to the physical conduit, so the CPU
port must explicitly keep another reference to it. This is also to
say: the user ports and their CPU ports may not always keep a
reference to the same conduit net device, and both are needed.
As for the conduit's kobject for the /sys/class/net/ entry, we don't
care about it, we can release it as soon as we hold the net device
object itself.
History and blame attribution
-----------------------------
The code has been refactored so many times, it is very difficult to
follow and properly attribute a blame, but I'll try to make a short
history which I hope to be correct.
We have two distinct probing paths:
- one for OF, introduced in 2016 in commit 83c0afaec7 ("net: dsa: Add
new binding implementation")
- one for non-OF, introduced in 2017 in commit 71e0bbde0d ("net: dsa:
Add support for platform data")
These are both complete rewrites of the original probing paths (which
used struct dsa_switch_driver and other weird stuff, instead of regular
devices on their respective buses for register access, like MDIO, SPI,
I2C etc):
- one for OF, introduced in 2013 in commit 5e95329b70 ("dsa: add
device tree bindings to register DSA switches")
- one for non-OF, introduced in 2008 in commit 91da11f870 ("net:
Distributed Switch Architecture protocol support")
except for tiny bits and pieces like dsa_dev_to_net_device() which were
seemingly carried over since the original commit, and used to this day.
The point is that the original probing paths received a fix in 2015 in
the form of commit 679fb46c57 ("net: dsa: Add missing master netdev
dev_put() calls"), but the fix never made it into the "new" (dsa2)
probing paths that can still be traced to today, and the fixed probing
path was later deleted in 2019 in commit 93e86b3bc8 ("net: dsa: Remove
legacy probing support").
That is to say, the new probing paths were never quite correct in this
area.
The existence of the legacy probing support which was deleted in 2019
explains why dsa_dev_to_net_device() returns a conduit with elevated
refcount (because it was supposed to be released during
dsa_remove_dst()). After the removal of the legacy code, the only user
of dsa_dev_to_net_device() calls dev_put(conduit) immediately after this
function returns. This pattern makes no sense today, and can only be
interpreted historically to understand why dev_hold() was there in the
first place.
Change details
--------------
Today we have a better netdev tracking infrastructure which we should
use. Logically netdev_hold() belongs in common code
(dsa_port_parse_cpu(), where dp->conduit is assigned), but there is a
tradeoff to be made with the rtnl_lock() section which would become a
bit too long if we did that - dsa_port_parse_cpu() also calls
request_module(). So we duplicate a bit of logic in order for the
callers of dsa_port_parse_cpu() to be the ones responsible of holding
the conduit reference and releasing it on error. This shortens the
rtnl_lock() section significantly.
In the dsa_switch_probe() error path, dsa_switch_release_ports() will be
called in a number of situations, one being where dsa_port_parse_cpu()
maybe didn't get the chance to run at all (a different port failed
earlier, etc). So we have to test for the conduit being NULL prior to
calling netdev_put().
There have still been so many transformations to the code since the
blamed commits (rename master -> conduit, commit 0650bf52b3 ("net:
dsa: be compatible with masters which unregister on shutdown")), that it
only makes sense to fix the code using the best methods available today
and see how it can be backported to stable later. I suspect the fix
cannot even be backported to kernels which lack dsa_switch_shutdown(),
and I suspect this is also maybe why the long-lived conduit reference
didn't make it into the new DSA probing paths at the time (problems
during shutdown).
Because dsa_dev_to_net_device() has a single call site and has to be
changed anyway, the logic was just absorbed into the non-OF
dsa_port_parse().
Tested on the ocelot/felix switch and on dsa_loop, both on the NXP
LS1028A with CONFIG_DEBUG_KOBJECT_RELEASE=y.
Reported-by: Ma Ke <make24@iscas.ac.cn>
Closes: https://lore.kernel.org/netdev/20251214131204.4684-1-make24@iscas.ac.cn/
Fixes: 83c0afaec7 ("net: dsa: Add new binding implementation")
Fixes: 71e0bbde0d ("net: dsa: Add support for platform data")
Reviewed-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20251215150236.3931670-1-vladimir.oltean@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Replace sprintf() calls with sysfs_emit() in guid_show(), size_show(),
and offset_show() sysfs attribute handlers. The sysfs_emit() function
provides automatic buffer bounds checking and is the preferred method
for formatting sysfs output per Documentation/filesystems/sysfs.rst.
This improves safety by preventing potential buffer overflows and aligns
with current kernel coding standards for sysfs attribute implementation.
Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Link: https://patch.msgid.link/20251218074833.2948801-1-kaushlendra.kumar@intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
In situations where no system memory is migrated to devmem, and in
upcoming patches where another GPU is performing the migration to
the newly allocated devmem buffer, there is nothing to ensure any
ongoing clear to the devmem allocation or async eviction from the
devmem allocation is complete.
Address that by passing a struct dma_fence down to the copy
functions, and ensure it is waited for before migration is marked
complete.
v3:
- New patch.
v4:
- Update the logic used for determining when to wait for the
pre_migrate_fence.
- Update the logic used for determining when to warn for the
pre_migrate_fence since the scheduler fences apparently
can signal out-of-order.
v5:
- Fix a UAF (CI)
- Remove references to source P2P migration (Himal)
- Put the pre_migrate_fence after migration.
v6:
- Pipeline the pre_migrate_fence dependency (Matt Brost)
Fixes: c5b3eb5a90 ("drm/xe: Add GPUSVM device memory copy vfunc functions")
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: <stable@vger.kernel.org> # v6.15+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-4-thomas.hellstrom@linux.intel.com
(cherry picked from commit 16b5ad3195)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Introduce an rw-semaphore to serialize migration to device if
it's likely that migration races with another device migration
of the same CPU address space range.
This is a temporary fix to attempt to mitigate a livelock that
might happen if many devices try to migrate a range at the same
time, and it affects only devices using the xe driver.
A longer term fix is probably improvements in the core mm
migration layer.
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-25-thomas.hellstrom@linux.intel.com
Support source interconnect migration by using the copy_to_ram() op
of the source device private pages.
Source interconnect migration is required to flush the L2 cache of
the source device, which among other things is a requirement for
correct global atomic operation. It also enables the source GPU to
potentially decompress any compressed content which is not
understood by peers, and finally for the PCIe case, it's expected
that writes over PCIe will be faster than reads.
The implementation can probably be improved by coalescing subregions
with the same source.
v5:
- Update waiting for the pre_migrate_fence and comments around that,
previously in another patch. (Himal).
- Actually select device private pages to migrate when
source_peer_migrates is true.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-24-thomas.hellstrom@linux.intel.com
Support destination migration over interconnect when migrating from
device-private pages with the same dev_pagemap owner.
Since we now also collect device-private pages to migrate,
also abort migration if the range to migrate is already
fully populated with pages from the desired pagemap.
Finally return -EBUSY from drm_pagemap_populate_mm()
if the migration can't be completed without first migrating all
pages in the range to system. It is expected that the caller
will perform that before retrying the call to
drm_pagemap_populate_mm().
v3:
- Fix a bug where the p2p dma-address was never used.
- Postpone enabling destination interconnect migration,
since xe devices require source interconnect migration to
ensure the source L2 cache is flushed at migration time.
- Update the drm_pagemap_migrate_to_devmem() interface to
pass migration details.
v4:
- Define XE_INTERCONNECT_P2P unconditionally (CI)
- Include a missing header (CI)
v5:
- Use page order increments where possible (Matt Brost).
- Fix a negated value of can_migrate_same_pagemap.
- Move removal of some dead code to a separate patch (Matt Brost).
- Remove an unnecessary zdd get() and put() (Matt Brost).
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-23-thomas.hellstrom@linux.intel.com
Use drm_gpusvm_scan_mm() to avoid unnecessarily calling into
drm_pagemap_populate_mm();
v3:
- New patch.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-22-thomas.hellstrom@linux.intel.com
With multi-device we are much more likely to have multiple
drm-gpusvm ranges pointing to the same struct mm range.
To avoid calling into drm_pagemap_populate_mm(), which is always
very costly, introduce a much less costly drm_gpusvm function,
drm_gpusvm_scan_mm() to scan the current migration state.
The device fault-handler and prefetcher can use this function to
determine whether migration is really necessary.
There are a couple of performance improvements that can be done
for this function if it turns out to be too costly. Those are
documented in the code.
v3:
- New patch.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-21-thomas.hellstrom@linux.intel.com
Use the dev_pagemap->owner field wherever possible, simplifying
the code slightly.
v3: New patch
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-20-thomas.hellstrom@linux.intel.com
As an aid to understanding the lifetime of the drm_pagemaps used
by the xe driver, document how the xe driver keeps the
drm_pagemap references.
v3:
- Fix formatting (Matt Brost)
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-19-thomas.hellstrom@linux.intel.com
Add debug printouts that are valueable for pagemap prefetch,
migration and page collection.
v2:
- Add additional debug prinouts around migration and page collection.
- Require CONFIG_DRM_XE_DEBUG_VM.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com> #v1
Link: https://patch.msgid.link/20251219113320.183860-18-thomas.hellstrom@linux.intel.com
Mimic the dma-buf method using dma_[map|unmap]_resource to map
for pcie-p2p dma.
There's an ongoing area of work upstream to sort out how this best
should be done. One method proposed is to add an additional
pci_p2p_dma_pagemap aliasing the device_private pagemap and use
the corresponding pci_p2p_dma_pagemap page as input for
dma_map_page(). However, that would incur double the amount of
memory and latency to set up the drm_pagemap and given the huge
amount of memory present on modern GPUs, that would really not work.
Hence the simple approach used in this patch.
v2:
- Simplify xe_page_to_pcie(). (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-17-thomas.hellstrom@linux.intel.com
Use device file descriptors and regions to represent pagemaps on
foreign or local devices.
The underlying files are type-checked at madvise time, and
references are kept on the drm_pagemap as long as there is are
madvises pointing to it.
Extend the madvise preferred_location UAPI to support the region
instance to identify the foreign placement.
v2:
- Improve UAPI documentation. (Matt Brost)
- Sanitize preferred_mem_loc.region_instance madvise. (Matt Brost)
- Clarify madvise drm_pagemap vs xe_pagemap refcounting. (Matt Brost)
- Don't allow a foreign drm_pagemap madvise without a fast
interconnect.
v3:
- Add a comment about reference-counting in xe_devmem_open() and
remove the reference-count get-and-put. (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-16-thomas.hellstrom@linux.intel.com
Honor the drm_pagemap vma attribute when migrating SVM pages.
Ensure that when the desired placement is validated as device
memory, that we also check that the requested drm_pagemap is
consistent with the current.
v2:
- Initialize a struct drm_pagemap pointer to NULL that could
otherwise be dereferenced uninitialized. (CI)
- Remove a redundant assignment (Matt Brost)
- Slightly improved commit message (Matt Brost)
- Extended drm_pagemap validation.
v3:
- Fix a compilation error if CONFIG_DRM_GPUSVM is not enabled.
(kernel test robot <lkp@intel.com>)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-14-thomas.hellstrom@linux.intel.com
As a consequence, struct xe_vma_mem_attr() can't simply be assigned
or freed without taking the reference count of individual members
into account. Also add helpers to do that.
v2:
- Move some calls to xe_vma_mem_attr_fini() to xe_vma_free(). (Matt Brost)
v3:
- Rebase.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com> #v2
Link: https://patch.msgid.link/20251219113320.183860-13-thomas.hellstrom@linux.intel.com
Register a driver-wide owner list, provide a callback to identify
fast interconnects and use the drm_pagemap_util helper to allocate
or reuse a suitable owner struct. For now we consider pagemaps on
different tiles on the same device as having fast interconnect and
thus the same owner.
v2:
- Fix up the error onion unwind in xe_pagemap_create(). (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-12-thomas.hellstrom@linux.intel.com
The hmm_range_fault() and the migration helpers currently need a common
"owner" to identify pagemaps and clients with fast interconnect.
Add a drm_pagemap utility to setup such owners by registering
drm_pagemaps, in a registry, and for each new drm_pagemap,
query which existing drm_pagemaps have fast interconnects with the new
drm_pagemap.
The "owner" scheme is limited in that it is static at drm_pagemap creation.
Ideally one would want the owner to be adjusted at run-time, but that
requires changes to hmm. If the proposed scheme becomes too limited,
we need to revisit.
v2:
- Improve documentation of DRM_PAGEMAP_OWNER_LIST_DEFINE(). (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-11-thomas.hellstrom@linux.intel.com
With the drm_pagemap_init() interface, drm_pagemap_create() is not
used anymore.
v2:
- Slightly more verbose commit message. (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-10-thomas.hellstrom@linux.intel.com
Define a struct xe_pagemap that embeds all pagemap-related
data used by xekmd, and use the drm_pagemap cache- and
shrinker to manage lifetime.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-9-thomas.hellstrom@linux.intel.com
Pagemaps are costly to set up and tear down, and they consume a lot
of system memory for the struct pages. Ideally they should be
created only when needed.
Add a caching mechanism to allow doing just that: Create the drm_pagemaps
when needed for migration. Keep them around to avoid destruction and
re-creation latencies and destroy inactive/unused drm_pagemaps on memory
pressure using a shrinker.
Only add the helper functions. They will be hooked up to the xe driver
in the upcoming patch.
v2:
- Add lockdep checking for drm_pagemap_put(). (Matt Brost)
- Add a copyright notice. (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-8-thomas.hellstrom@linux.intel.com
If a device holds a reference on a foregin device's drm_pagemap,
and a device unbind is executed on the foreign device,
Typically that foreign device would evict its device-private
pages and then continue its device-managed cleanup eventually
releasing its drm device and possibly allow for module unload.
However, since we're still holding a reference on a drm_pagemap,
when that reference is released and the provider module is
unloaded we'd execute out of undefined memory.
Therefore keep a reference on the provider device and module until
the last drm_pagemap reference is gone.
Note that in theory, the drm_gpusvm_helper module may be unloaded
as soon as the final module_put() of the provider driver module is
executed, so we need to add a module_exit() function that waits
for the work item executing the module_put() has completed.
v2:
- Better commit message (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-7-thomas.hellstrom@linux.intel.com
To be able to keep track of drm_pagemap usage, add a refcounted
backpointer to struct drm_pagemap_zdd. This will keep the drm_pagemap
reference count from dropping to zero as long as there are drm_pagemap
pages present in a CPU address space.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-6-thomas.hellstrom@linux.intel.com
With the end goal of being able to free unused pagemaps
and allocate them on demand, add a refcount to struct drm_pagemap,
remove the xe embedded drm_pagemap, allocating and freeing it
explicitly.
v2:
- Make the drm_pagemap pointer in drm_gpusvm_pages reference-counted.
v3:
- Call drm_pagemap_get() before drm_pagemap_put() in drm_gpusvm_pages
(Himal Prasad Ghimiray)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com> #v1
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-5-thomas.hellstrom@linux.intel.com
In situations where no system memory is migrated to devmem, and in
upcoming patches where another GPU is performing the migration to
the newly allocated devmem buffer, there is nothing to ensure any
ongoing clear to the devmem allocation or async eviction from the
devmem allocation is complete.
Address that by passing a struct dma_fence down to the copy
functions, and ensure it is waited for before migration is marked
complete.
v3:
- New patch.
v4:
- Update the logic used for determining when to wait for the
pre_migrate_fence.
- Update the logic used for determining when to warn for the
pre_migrate_fence since the scheduler fences apparently
can signal out-of-order.
v5:
- Fix a UAF (CI)
- Remove references to source P2P migration (Himal)
- Put the pre_migrate_fence after migration.
v6:
- Pipeline the pre_migrate_fence dependency (Matt Brost)
Fixes: c5b3eb5a90 ("drm/xe: Add GPUSVM device memory copy vfunc functions")
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: <stable@vger.kernel.org> # v6.15+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-4-thomas.hellstrom@linux.intel.com
The page pointer can't be NULL.
v5:
- New patch. (Matt Brost)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-3-thomas.hellstrom@linux.intel.com
Since airoha_probe() is not executed under rtnl lock, there is small race
where a given device is configured by user-space while the remaining ones
are not completely loaded from the dts yet. This condition will allow a
hw device misconfiguration since there are some conditions (e.g. GDM2 check
in airoha_dev_init()) that require all device are properly loaded from the
device tree. Fix the issue moving net_devices registration at the end of
the airoha_probe routine.
Fixes: 9cd451d414 ("net: airoha: Add loopback support for GDM2")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251214-airoha-fix-dev-registration-v1-1-860e027ad4c6@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The Renesas RZ/N2H (R9A09G087) SoC has the same Interrupt Controller
(ICU) as the Renesas RZ/T2H (R9A09G077) SoC.
Enable support for it by selecting the RENESAS_RZT2H_ICU config.
Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20251216123421.124401-1-cosmin-gabriel.tanislav.xa@renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
The struct ip_tunnel_info has a flexible array member named
options that is protected by a counted_by(options_len)
attribute.
The compiler will use this information to enforce runtime bounds
checking deployed by FORTIFY_SOURCE string helpers.
As laid out in the GCC documentation, the counter must be
initialized before the first reference to the flexible array
member.
After scanning through the files that use struct ip_tunnel_info
and also refer to options or options_len, it appears the normal
case is to use the ip_tunnel_info_opts_set() helper.
Said helper would initialize options_len properly before copying
data into options, however in the GRE ERSPAN code a partial
update is done, preventing the use of the helper function.
Before this change the handling of ERSPAN traffic in GRE tunnels
would cause a kernel panic when the kernel is compiled with
GCC 15+ and having FORTIFY_SOURCE configured:
memcpy: detected buffer overflow: 4 byte write of buffer size 0
Call Trace:
<IRQ>
__fortify_panic+0xd/0xf
erspan_rcv.cold+0x68/0x83
? ip_route_input_slow+0x816/0x9d0
gre_rcv+0x1b2/0x1c0
gre_rcv+0x8e/0x100
? raw_v4_input+0x2a0/0x2b0
ip_protocol_deliver_rcu+0x1ea/0x210
ip_local_deliver_finish+0x86/0x110
ip_local_deliver+0x65/0x110
? ip_rcv_finish_core+0xd6/0x360
ip_rcv+0x186/0x1a0
Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-counted_005fby-variable-attribute
Reported-at: https://launchpad.net/bugs/2129580
Fixes: bb5e62f2d5 ("net: Add options as a flexible array to struct ip_tunnel_info")
Signed-off-by: Frode Nordahl <fnordahl@ubuntu.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251213101338.4693-1-fnordahl@ubuntu.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Matthieu Baerts says:
====================
mptcp: fix warn on bad status
Two somewhat related fixes addressing different issues found by
syzkaller, and producing the exact same splat: a WARNING in
subflow_data_ready().
- Patch 1: fallback earlier on simultaneous connections to avoid a
warning. A fix for v5.19.
- Patch 2: ensure context reset on disconnect, also to avoid a similar
warning. A fix for v6.2.
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
====================
Link: https://patch.msgid.link/20251212-net-mptcp-subflow_data_ready-warn-v1-0-d1f9fd1c36c8@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Syzkaller reports a simult-connect race leading to inconsistent fallback
status:
WARNING: CPU: 3 PID: 33 at net/mptcp/subflow.c:1515 subflow_data_ready+0x40b/0x7c0 net/mptcp/subflow.c:1515
Modules linked in:
CPU: 3 UID: 0 PID: 33 Comm: ksoftirqd/3 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:subflow_data_ready+0x40b/0x7c0 net/mptcp/subflow.c:1515
Code: 89 ee e8 78 61 3c f6 40 84 ed 75 21 e8 8e 66 3c f6 44 89 fe bf 07 00 00 00 e8 c1 61 3c f6 41 83 ff 07 74 09 e8 76 66 3c f6 90 <0f> 0b 90 e8 6d 66 3c f6 48 89 df e8 e5 ad ff ff 31 ff 89 c5 89 c6
RSP: 0018:ffffc900006cf338 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888031acd100 RCX: ffffffff8b7f2abf
RDX: ffff88801e6ea440 RSI: ffffffff8b7f2aca RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000004 R11: 0000000000002c10 R12: ffff88802ba69900
R13: 1ffff920000d9e67 R14: ffff888046f81800 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff8880d69bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560fc0ca1670 CR3: 0000000032c3a000 CR4: 0000000000352ef0
Call Trace:
<TASK>
tcp_data_queue+0x13b0/0x4f90 net/ipv4/tcp_input.c:5197
tcp_rcv_state_process+0xfdf/0x4ec0 net/ipv4/tcp_input.c:6922
tcp_v6_do_rcv+0x492/0x1740 net/ipv6/tcp_ipv6.c:1672
tcp_v6_rcv+0x2976/0x41e0 net/ipv6/tcp_ipv6.c:1918
ip6_protocol_deliver_rcu+0x188/0x1520 net/ipv6/ip6_input.c:438
ip6_input_finish+0x1e4/0x4b0 net/ipv6/ip6_input.c:489
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ip6_input+0x105/0x2f0 net/ipv6/ip6_input.c:500
dst_input include/net/dst.h:471 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ipv6_rcv+0x264/0x650 net/ipv6/ip6_input.c:311
__netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:5979
__netif_receive_skb+0x1d/0x160 net/core/dev.c:6092
process_backlog+0x442/0x15e0 net/core/dev.c:6444
__napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7494
napi_poll net/core/dev.c:7557 [inline]
net_rx_action+0xa9f/0xfe0 net/core/dev.c:7684
handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
run_ksoftirqd kernel/softirq.c:968 [inline]
run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960
smpboot_thread_fn+0x3f7/0xae0 kernel/smpboot.c:160
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
The TCP subflow can process the simult-connect syn-ack packet after
transitioning to TCP_FIN1 state, bypassing the MPTCP fallback check,
as the sk_state_change() callback is not invoked for * -> FIN_WAIT1
transitions.
That will move the msk socket to an inconsistent status and the next
incoming data will hit the reported splat.
Close the race moving the simult-fallback check at the earliest possible
stage - that is at syn-ack generation time.
About the fixes tags: [2] was supposed to also fix this issue introduced
by [3]. [1] is required as a dependence: it was not explicitly marked as
a fix, but it is one and it has already been backported before [3]. In
other words, this commit should be backported up to [3], including [2]
and [1] if that's not already there.
Fixes: 23e89e8ee7 ("tcp: Don't drop SYN+ACK for simultaneous connect().") [1]
Fixes: 4fd19a3070 ("mptcp: fix inconsistent state on fastopen race") [2]
Fixes: 1e777f39b4 ("mptcp: add MSG_FASTOPEN sendmsg flag support") [3]
Cc: stable@vger.kernel.org
Reported-by: syzbot+0ff6b771b4f7a5bce83b@syzkaller.appspotmail.com
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/586
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251212-net-mptcp-subflow_data_ready-warn-v1-1-d1f9fd1c36c8@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The driver already has debug messages for memcpy and linear transfers,
but is missing them for cyclic transfers.
Cyclic transfers are one of the main uses of the DMA controller, used
for audio data transfers. And since these are likely the first DMA
peripherals to be enabled, it helps to have these debug messages.
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@kernel.org>
Link: https://patch.msgid.link/20251221064754.1783369-1-wens@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
maxburst, as provided by the client, specifies the largest amount of
data that is allowed to be transferred in one burst. This limit is
normally provided to avoid a data burst overflowing the target FIFO.
It does not mean that the DMA engine can only do bursts in that size.
Let the driver pick the largest supported burst length within the
given limit. This lets the driver work correctly with some clients that
give a large maxburst value. In particular, the 8250_dw driver will give
a quarter of the UART's FIFO size as maxburst. On some systems the FIFO
size is 256 bytes, giving a maxburst of 64 bytes, while the hardware
only supports bursts of up to 16 bytes.
Signed-off-by: Chen-Yu Tsai <wens@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20251221080450.1813479-1-wens@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Using libc types and headers from the UAPI headers is problematic as it
introduces a dependency on a full C toolchain.
Use the fixed-width integer types provided by the UAPI headers instead.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20251222-uapi-idxd-v1-1-baa183adb20d@linutronix.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Clobbering an error value to be returned from shdma_tx_submit() with
a pm_runtime_put() return value is not particularly useful, especially
if the latter is 0, so stop doing that.
This will facilitate a planned change of the pm_runtime_put() return
type to void in the future.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/9626129.rMLUfLXkoz@rafael.j.wysocki
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add qcom,soundwire-v2.2.0 to the list of supported Qualcomm
SoundWire controller versions. This version falls back to
qcom,soundwire-v2.0.0 if not explicitly handled by the driver.
Signed-off-by: Jingyi Wang <jingyi.wang@oss.qualcomm.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Prasad Kumpatla <prasad.kumpatla@oss.qualcomm.com>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
Link: https://patch.msgid.link/20251105-knp-audio-v2-v4-1-ae0953f02b44@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
These are nearly identical to the respective driver callbacks. The only
differences are that .remove() returns void instead of int and .shutdown()
has to cope for unbound devices.
The objective is to get rid of users of struct device_driver callbacks
.probe(), .remove() and .shutdown() to eventually remove these.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20251215174925.1327021-6-u.kleine-koenig@baylibre.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
All remove functions return zero and the driver core ignores any other
returned value (just emits a warning about it being ignored). So make all
remove callbacks return void instead of an ignored int. This is in line
with most other subsystems.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20251215174925.1327021-5-u.kleine-koenig@baylibre.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The -EEXIST error code is reserved by the module loading infrastructure
to indicate that a module is already loaded. When a module's init
function returns -EEXIST, userspace tools like kmod interpret this as
"module already loaded" and treat the operation as successful, returning
0 to the user even though the module initialization actually failed.
This follows the precedent set by commit 54416fd767 ("netfilter:
conntrack: helper: Replace -EEXIST by -EBUSY") which fixed the same
issue in nf_conntrack_helper_register().
This affects bpf_crypto_skcipher module. While the configuration
required to build it as a module is unlikely in practice, it is
technically possible, so fix it for correctness.
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Acked-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://lore.kernel.org/r/20251220-dev-module-init-eexists-bpf-v1-1-7f186663dbe7@samsung.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
As the previous commit allowed raw_tp programs to call kfuncs, so of the
selftests that were expected to fail will now succeed.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251222133250.1890587-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Associate raw tracepoint program type with the kfunc tracing hook. This
allows calling kfuncs from raw_tp programs.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251222133250.1890587-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Roman Gushchin says:
====================
mm: bpf kfuncs to access memcg data
Introduce kfuncs to simplify the access to the memcg data.
These kfuncs can be used to accelerate monitoring use cases and
for implementing custom OOM policies once BPF OOM is landed.
This patchset was separated out from the BPF OOM patchset to simplify
the logistics and accelerate the landing of the part which is useful
by itself. No functional changes since BPF OOM v2.
v4:
- refactored memcg vm event and stat item idx checks (by Alexei)
v3:
- dropped redundant kfuncs flags (by Alexei)
- fixed kdocs warnings (by Alexei)
- merged memcg stats access patches into one (by Alexei)
- restored root memcg usage reporting, added a comment
- added checks for enum boundaries
- added Shakeel and JP as co-maintainers (by Shakeel)
v2:
- added mem_cgroup_disabled() checks (by Shakeel B.)
- added special handling of the root memcg in bpf_mem_cgroup_usage()
(by Shakeel B.)
- minor fixes in the kselftest (by Shakeel B.)
- added a MAINTAINERS entry (by Shakeel B.)
v1:
https://lore.kernel.org/bpf/87ike29s5r.fsf@linux.dev/T/#t
====================
Link: https://patch.msgid.link/20251223044156.208250-1-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
