CVE-2023-52749

In the Linux kernel, the following vulnerability has been resolved: spi:
Fix null dereference on suspend A race condition exists where a synchronous
(noqueue) transfer can be active during a system suspend. This can cause a
null pointer dereference exception to occur when the system resumes.
Example order of events leading to the exception: 1. spi_sync() calls
__spi_transfer_message_noqueue() which sets ctlr->cur_msg 2. Spi transfer
begins via spi_transfer_one_message() 3. System is suspended interrupting
the transfer context 4. System is resumed 6. spi_controller_resume() calls
spi_start_queue() which resets cur_msg to NULL 7. Spi transfer context
resumes and spi_finalize_current_message() is called which dereferences
cur_msg (which is now NULL) Wait for synchronous transfers to complete
before suspending by acquiring the bus mutex and setting/checking a suspend
flag.