linux-stable.git/drivers/net/ethernet/amd, branch linux-6.8.y

pds_core: Fix pdsc_check_pci_health function to use work thread

2024-04-17T09:23:31+00:00

[ Upstream commit 81665adf25d28a00a986533f1d3a5df76b79cad9 ]

When the driver notices fw_status == 0xff it tries to perform a PCI
reset on itself via pci_reset_function() in the context of the driver's
health thread. However, pdsc_reset_prepare calls
pdsc_stop_health_thread(), which attempts to stop/flush the health
thread. This results in a deadlock because the stop/flush will never
complete since the driver called pci_reset_function() from the health
thread context. Fix by changing the pdsc_check_pci_health_function()
to queue a newly introduced pdsc_pci_reset_thread() on the pdsc's
work queue.

Unloading the driver in the fw_down/dead state uncovered another issue,
which can be seen in the following trace:

WARNING: CPU: 51 PID: 6914 at kernel/workqueue.c:1450 __queue_work+0x358/0x440
[...]
RIP: 0010:__queue_work+0x358/0x440
[...]
Call Trace:
 
 ? __warn+0x85/0x140
 ? __queue_work+0x358/0x440
 ? report_bug+0xfc/0x1e0
 ? handle_bug+0x3f/0x70
 ? exc_invalid_op+0x17/0x70
 ? asm_exc_invalid_op+0x1a/0x20
 ? __queue_work+0x358/0x440
 queue_work_on+0x28/0x30
 pdsc_devcmd_locked+0x96/0xe0 [pds_core]
 pdsc_devcmd_reset+0x71/0xb0 [pds_core]
 pdsc_teardown+0x51/0xe0 [pds_core]
 pdsc_remove+0x106/0x200 [pds_core]
 pci_device_remove+0x37/0xc0
 device_release_driver_internal+0xae/0x140
 driver_detach+0x48/0x90
 bus_remove_driver+0x6d/0xf0
 pci_unregister_driver+0x2e/0xa0
 pdsc_cleanup_module+0x10/0x780 [pds_core]
 __x64_sys_delete_module+0x142/0x2b0
 ? syscall_trace_enter.isra.18+0x126/0x1a0
 do_syscall_64+0x3b/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7fbd9d03a14b
[...]

Fix this by preventing the devcmd reset if the FW is not running.

Fixes: d9407ff11809 ("pds_core: Prevent health thread from running during reset/remove")
Reviewed-by: Shannon Nelson 
Signed-off-by: Brett Creeley 
Reviewed-by: Jacob Keller 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

pds_core: use pci_reset_function for health reset

2024-04-17T09:23:31+00:00

[ Upstream commit 2cbab3c296f1addd73b40549a2271b30f960df8b ]

We get the benefit of all the PCI reset locking and recovery if
we use the existing pci_reset_function() that will call our
local reset handlers.

Reviewed-by: Brett Creeley 
Signed-off-by: Shannon Nelson 
Signed-off-by: David S. Miller 
Stable-dep-of: 81665adf25d2 ("pds_core: Fix pdsc_check_pci_health function to use work thread")
Signed-off-by: Sasha Levin

net: pds_core: Fix possible double free in error handling path

2024-03-07T11:03:19+00:00

When auxiliary_device_add() returns error and then calls
auxiliary_device_uninit(), Callback function pdsc_auxbus_dev_release
calls kfree(padev) to free memory. We shouldn't call kfree(padev)
again in the error handling path.

Fix this by cleaning up the redundant kfree() and putting
the error handling back to where the errors happened.

Fixes: 4569cce43bc6 ("pds_core: add auxiliary_bus devices")
Signed-off-by: Yongzhi Liu 
Reviewed-by: Wojciech Drewek 
Reviewed-by: Shannon Nelson 
Link: https://lore.kernel.org/r/20240306105714.20597-1-hyperlyzcs@gmail.com
Signed-off-by: Paolo Abeni

pds_core: no health-thread in VF path

2024-02-13T01:38:01+00:00

The VFs don't run the health thread, so don't try to
stop or restart the non-existent timer or work item.

Fixes: d9407ff11809 ("pds_core: Prevent health thread from running during reset/remove")
Reviewed-by: Brett Creeley 
Signed-off-by: Shannon Nelson 
Link: https://lore.kernel.org/r/20240210002002.49483-1-shannon.nelson@amd.com
Signed-off-by: Jakub Kicinski

pds_core: Rework teardown/setup flow to be more common

2024-02-01T02:26:59+00:00

Currently the teardown/setup flow for driver probe/remove is quite
a bit different from the reset flows in pdsc_fw_down()/pdsc_fw_up().
One key piece that's missing are the calls to pci_alloc_irq_vectors()
and pci_free_irq_vectors(). The pcie reset case is calling
pci_free_irq_vectors() on reset_prepare, but not calling the
corresponding pci_alloc_irq_vectors() on reset_done. This is causing
unexpected/unwanted interrupt behavior due to the adminq interrupt
being accidentally put into legacy interrupt mode. Also, the
pci_alloc_irq_vectors()/pci_free_irq_vectors() functions are being
called directly in probe/remove respectively.

Fix this inconsistency by making the following changes:
  1. Always call pdsc_dev_init() in pdsc_setup(), which calls
     pci_alloc_irq_vectors() and get rid of the now unused
     pds_dev_reinit().
  2. Always free/clear the pdsc->intr_info in pdsc_teardown()
     since this structure will get re-alloced in pdsc_setup().
  3. Move the calls of pci_free_irq_vectors() to pdsc_teardown()
     since pci_alloc_irq_vectors() will always be called in
     pdsc_setup()->pdsc_dev_init() for both the probe/remove and
     reset flows.
  4. Make sure to only create the debugfs "identity" entry when it
     doesn't already exist, which it will in the reset case because
     it's already been created in the initial call to pdsc_dev_init().

Fixes: ffa55858330f ("pds_core: implement pci reset handlers")
Signed-off-by: Brett Creeley 
Reviewed-by: Shannon Nelson 
Link: https://lore.kernel.org/r/20240129234035.69802-7-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski

pds_core: Clear BARs on reset

2024-02-01T02:26:59+00:00

During reset the BARs might be accessed when they are
unmapped. This can cause unexpected issues, so fix it by
clearing the cached BAR values so they are not accessed
until they are re-mapped.

Also, make sure any places that can access the BARs
when they are NULL are prevented.

Fixes: 49ce92fbee0b ("pds_core: add FW update feature to devlink")
Signed-off-by: Brett Creeley 
Reviewed-by: Shannon Nelson 
Reviewed-by: Przemek Kitszel 
Link: https://lore.kernel.org/r/20240129234035.69802-6-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski

pds_core: Prevent race issues involving the adminq

2024-02-01T02:26:59+00:00

There are multiple paths that can result in using the pdsc's
adminq.

[1] pdsc_adminq_isr and the resulting work from queue_work(),
    i.e. pdsc_work_thread()->pdsc_process_adminq()

[2] pdsc_adminq_post()

When the device goes through reset via PCIe reset and/or
a fw_down/fw_up cycle due to bad PCIe state or bad device
state the adminq is destroyed and recreated.

A NULL pointer dereference can happen if [1] or [2] happens
after the adminq is already destroyed.

In order to fix this, add some further state checks and
implement reference counting for adminq uses. Reference
counting was used because multiple threads can attempt to
access the adminq at the same time via [1] or [2]. Additionally,
multiple clients (i.e. pds-vfio-pci) can be using [2]
at the same time.

The adminq_refcnt is initialized to 1 when the adminq has been
allocated and is ready to use. Users/clients of the adminq
(i.e. [1] and [2]) will increment the refcnt when they are using
the adminq. When the driver goes into a fw_down cycle it will
set the PDSC_S_FW_DEAD bit and then wait for the adminq_refcnt
to hit 1. Setting the PDSC_S_FW_DEAD before waiting will prevent
any further adminq_refcnt increments. Waiting for the
adminq_refcnt to hit 1 allows for any current users of the adminq
to finish before the driver frees the adminq. Once the
adminq_refcnt hits 1 the driver clears the refcnt to signify that
the adminq is deleted and cannot be used. On the fw_up cycle the
driver will once again initialize the adminq_refcnt to 1 allowing
the adminq to be used again.

Fixes: 01ba61b55b20 ("pds_core: Add adminq processing and commands")
Signed-off-by: Brett Creeley 
Reviewed-by: Shannon Nelson 
Reviewed-by: Przemek Kitszel 
Link: https://lore.kernel.org/r/20240129234035.69802-5-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski

pds_core: Use struct pdsc for the pdsc_adminq_isr private data

2024-02-01T02:26:59+00:00

The initial design for the adminq interrupt was done based
on client drivers having their own adminq and adminq
interrupt. So, each client driver's adminq isr would use
their specific adminqcq for the private data struct. For the
time being the design has changed to only use a single
adminq for all clients. So, instead use the struct pdsc for
the private data to simplify things a bit.

This also has the benefit of not dereferencing the adminqcq
to access the pdsc struct when the PDSC_S_STOPPING_DRIVER bit
is set and the adminqcq has actually been cleared/freed.

Fixes: 01ba61b55b20 ("pds_core: Add adminq processing and commands")
Signed-off-by: Brett Creeley 
Reviewed-by: Shannon Nelson 
Reviewed-by: Przemek Kitszel 
Link: https://lore.kernel.org/r/20240129234035.69802-4-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski

pds_core: Cancel AQ work on teardown

2024-02-01T02:26:59+00:00

There is a small window where pdsc_work_thread()
calls pdsc_process_adminq() and pdsc_process_adminq()
passes the PDSC_S_STOPPING_DRIVER check and starts
to process adminq/notifyq work and then the driver
starts a fw_down cycle. This could cause some
undefined behavior if the notifyqcq/adminqcq are
free'd while pdsc_process_adminq() is running. Use
cancel_work_sync() on the adminqcq's work struct
to make sure any pending work items are cancelled
and any in progress work items are completed.

Also, make sure to not call cancel_work_sync() if
the work item has not be initialized. Without this,
traces will happen in cases where a reset fails and
teardown is called again or if reset fails and the
driver is removed.

Fixes: 01ba61b55b20 ("pds_core: Add adminq processing and commands")
Signed-off-by: Brett Creeley 
Reviewed-by: Shannon Nelson 
Reviewed-by: Przemek Kitszel 
Link: https://lore.kernel.org/r/20240129234035.69802-3-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski

pds_core: Prevent health thread from running during reset/remove

2024-02-01T02:26:58+00:00

The PCIe reset handlers can run at the same time as the
health thread. This can cause the health thread to
stomp on the PCIe reset. Fix this by preventing the
health thread from running while a PCIe reset is happening.

As part of this use timer_shutdown_sync() during reset and
remove to make sure the timer doesn't ever get rearmed.

Fixes: ffa55858330f ("pds_core: implement pci reset handlers")
Signed-off-by: Brett Creeley 
Reviewed-by: Shannon Nelson 
Reviewed-by: Przemek Kitszel 
Link: https://lore.kernel.org/r/20240129234035.69802-2-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski