0946b9263e
[ Upstream commit f275a4659484716259cc46268d9043424e51cf0f ]
The driver's interrupt handler checks whether a message is currently
being handled with the curr_msg pointer. When it is NULL, the interrupt
is considered to be unexpected. Similarly, the i2c_start_transfer
routine checks for the remaining number of messages to handle in
num_msgs.
However, these values are never cleared and always keep the message and
number relevant to the latest transfer (which might be done already and
the underlying message memory might have been freed).
When an unexpected interrupt hits with the DONE bit set, the isr will
then try to access the flags field of the curr_msg structure, leading
to a fatal page fault.
The msg_buf and msg_buf_remaining fields are also never cleared at the
end of the transfer, which can lead to similar pitfalls.
Fix these issues by introducing a cleanup function and always calling
it after a transfer is finished.
Fixes: e2474541032d ("i2c: bcm2835: Fix hang for writing messages larger than 16 bytes")
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.