On 9/12/25 18:59, Shinichiro Kawasaki wrote:
> On Sep 12, 2025 / 16:31, Damien Le Moal wrote:
>> On 9/12/25 16:11, Shin'ichiro Kawasaki wrote:
>>> When endpoint controller driver is immature, the fields dma_chan_tx and
>>> dma_chan_rx of the struct pci_epf_test could be NULL even after epf
>>> initialization. However, pci_epf_test_clean_dma_chan() assumes that they
>>> are always non-NULL valid values, and causes kernel panic when the
>>> fields are NULL. To avoid the kernel panic, NULL check the fields before
>>> release.
>>>
>>> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
>>> ---
>>> drivers/pci/endpoint/functions/pci-epf-test.c | 17 +++++++++++------
>>> 1 file changed, 11 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> index e091193bd8a8..1c29d5dd4382 100644
>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> @@ -301,15 +301,20 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test)
>>> if (!epf_test->dma_supported)
>>> return;
>>>
>>> - dma_release_channel(epf_test->dma_chan_tx);
>>> - if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) {
>>> + if (epf_test->dma_chan_tx) {
>>> + dma_release_channel(epf_test->dma_chan_tx);
>>> + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) {
>>> + epf_test->dma_chan_tx = NULL;
>>> + epf_test->dma_chan_rx = NULL;
>>> + return;
>>> + }
>>> epf_test->dma_chan_tx = NULL;
>>> - epf_test->dma_chan_rx = NULL;
>>> - return;
>>> }
>>
>> Can we simplify here ?
>
> I'm afraid, no,
>
>>
>> if (epf_test->dma_chan_tx) {
>> dma_release_channel(epf_test->dma_chan_tx);
>> epf_test->dma_chan_tx = NULL;
>
> because the line above affects the comparison below.
Arg... Of course ! Sorry about the noise.
>
>> if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) {
>> epf_test->dma_chan_rx = NULL;
>> return;
>> }
>> }
>>
>>>
>>> - dma_release_channel(epf_test->dma_chan_rx);
>>> - epf_test->dma_chan_rx = NULL;
>>> + if (epf_test->dma_chan_rx) {
>>> + dma_release_channel(epf_test->dma_chan_rx);
>>> + epf_test->dma_chan_rx = NULL;
>>> + }
>>> }
>>>
>>> static void pci_epf_test_print_rate(struct pci_epf_test *epf_test,
>>
>>
>> --
>> Damien Le Moal
>> Western Digital Research
--
Damien Le Moal
Western Digital Research
