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crypto: qat - use unmanaged allocation for dc_data

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The dc_data structure holds data required for handling compression
operations, such as overflow buffers. In this context, the use of
managed memory allocation APIs (devm_kzalloc() and devm_kfree())
is not necessary, as these data structures are freed and
re-allocated when a device is restarted in adf_dev_down() and
adf_dev_up().

Additionally, managed APIs automatically handle memory cleanup when the
device is detached, which can lead to conflicts with manual cleanup
processes. Specifically, if a device driver invokes the adf_dev_down()
function as part of the cleanup registered with
devm_add_action_or_reset(), it may attempt to free memory that is also
managed by the device's resource management system, potentially leading
to a double-free.

This might result in a warning similar to the following when unloading
the device specific driver, for example qat_6xxx.ko:

    qat_free_dc_data+0x4f/0x60 [intel_qat]
    qat_compression_event_handler+0x3d/0x1d0 [intel_qat]
    adf_dev_shutdown+0x6d/0x1a0 [intel_qat]
    adf_dev_down+0x32/0x50 [intel_qat]
    devres_release_all+0xb8/0x110
    device_unbind_cleanup+0xe/0x70
    device_release_driver_internal+0x1c1/0x200
    driver_detach+0x48/0x90
    bus_remove_driver+0x74/0xf0
    pci_unregister_driver+0x2e/0xb0

Use unmanaged memory allocation APIs (kzalloc_node() and kfree()) for
the dc_data structure. This ensures that memory is explicitly allocated
and freed under the control of the driver code, preventing manual
deallocation from interfering with automatic cleanup.

Fixes: 1198ae56c9 ("crypto: qat - expose deflate through acomp api for QAT GEN2")
Signed-off-by: Suman Kumar Chakraborty <suman.kumar.chakraborty@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Suman Kumar Chakraborty 2025-05-22 09:21:41 +01:00 • committed by Herbert Xu
parent 9d50a25eeb
commit 4cc871ad01
1 changed files with 2 additions and 2 deletions
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4
drivers/crypto/intel/qat/qat_common/qat_compression.c
View file

@ -196,7 +196,7 @@ static int qat_compression_alloc_dc_data(struct adf_accel_dev *accel_dev)
struct adf_dc_data *dc_data = NULL;
u8 *obuff = NULL;
dc_data = devm_kzalloc(dev, sizeof(*dc_data), GFP_KERNEL);
dc_data = kzalloc_node(sizeof(*dc_data), GFP_KERNEL, dev_to_node(dev));
if (!dc_data)
goto err;
@ -234,7 +234,7 @@ static void qat_free_dc_data(struct adf_accel_dev *accel_dev)
dma_unmap_single(dev, dc_data->ovf_buff_p, dc_data->ovf_buff_sz,
DMA_FROM_DEVICE);
kfree_sensitive(dc_data->ovf_buff);
devm_kfree(dev, dc_data);
kfree(dc_data);
accel_dev->dc_data = NULL;
}