Hello Alain Volmat,
The patch 4f2b39dc2d14: "spi: stm32: use dmaengine_terminate_{a}sync
instead of _all" from Jun 15, 2023 (linux-next), leads to the
following Smatch static checker warning:
include/linux/dmaengine.h:1185 dmaengine_terminate_sync()
warn: sleeping in atomic context
./include/linux/dmaengine.h
1177 static inline int dmaengine_terminate_sync(struct dma_chan *chan)
1178 {
1179 int ret;
1180
1181 ret = dmaengine_terminate_async(chan);
1182 if (ret)
1183 return ret;
1184
--> 1185 dmaengine_synchronize(chan);
1186
1187 return 0;
1188 }
The problem is that the error handling code calls dmaengine_terminate_sync()
while holding a spinlock.
stm32_spi_transfer_one_dma() <- disables preempt
-> dmaengine_terminate_sync()
It used to be dmaengine_terminate_all(). Probably that was buggy as
well, but just too complicated for Smatch to warn about. Another idea
is to call dmaengine_terminate_async() (I don't know the code at all,
possibly that is a stupid idea).
regards,
dan carpenter
