Ok, I can add a check in another patch. Should we return NULL pointer if msg->len is 0 or print out some warnings? Thanks. On Fri, Feb 15, 2019 at 5:10 PM Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote: > > On Fri, Feb 15, 2019 at 05:02:02PM +0800, Hsin-Yi Wang wrote: > > i2c_get_dma_safe_msg_buf() allocates space based on msg->len. If threshold is > > 0 and msg->len is also 0, function makes zero-length allocation, which returns > > a special ZERO_SIZE_PTR instead of a NULL pointer, and this will cause later > > code to fail. Modify the threshold to > 0 so the function returns NULL pointer. > > > > Fixes: fc66b39fe36a ("i2c: mediatek: Use DMA safe buffers for i2c transactions") > > Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> > > Right. But we need to fix i2c_get_dma_safe_msg_buf(), so it will be > handled for all callers. Do you want to add a check if msg->len is 0 or > shall I? Both fine for me. >