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Douglas Anderson c75a66726d spi: spi-geni-qcom: Fix geni_spi_isr() NULL dereference in timeout case 
commit 4aa1464acb upstream.

In commit 7ba9bdcb91 ("spi: spi-geni-qcom: Don't keep a local state
variable") we changed handle_fifo_timeout() so that we set
"mas->cur_xfer" to NULL to make absolutely sure that we don't mess
with the buffers from the previous transfer in the timeout case.

Unfortunately, this caused the IRQ handler to dereference NULL in some
cases.  One case:

  CPU0                           CPU1
  ----                           ----
                                 setup_fifo_xfer()
                                  geni_se_setup_m_cmd()
                                 <hardware starts transfer>
                                 <transfer completes in hardware>
                                 <hardware sets M_RX_FIFO_WATERMARK_EN in m_irq>
                                 ...
                                 handle_fifo_timeout()
                                  spin_lock_irq(mas->lock)
                                  mas->cur_xfer = NULL
                                  geni_se_cancel_m_cmd()
                                  spin_unlock_irq(mas->lock)

  geni_spi_isr()
   spin_lock(mas->lock)
   if (m_irq & M_RX_FIFO_WATERMARK_EN)
    geni_spi_handle_rx()
     mas->cur_xfer NULL dereference!

tl;dr: Seriously delayed interrupts for RX/TX can lead to timeout
handling setting mas->cur_xfer to NULL.

Let's check for the NULL transfer in the TX and RX cases and reset the
watermark or clear out the fifo respectively to put the hardware back
into a sane state.

NOTE: things still could get confused if we get timeouts all the way
through handle_fifo_timeout() and then start a new transfer because
interrupts from the old transfer / cancel / abort could still be
pending.  A future patch will help this corner case.

Fixes: 561de45f72 ("spi: spi-geni-qcom: Add SPI driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20201217142842.v3.1.I99ee04f0cb823415df59bd4f550d6ff5756e43d6@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-17 14:17:00 +01:00
arch ARM: OMAP2+: omap_device: fix idling of devices during probe 2021-01-17 14:16:59 +01:00
block blk-iocost: fix NULL iocg deref from racing against initialization 2021-01-12 20:18:23 +01:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: asym_tpm: correct zero out potential secrets 2021-01-12 20:18:17 +01:00
Documentation dt-bindings: rtc: add reset-source property 2021-01-09 13:46:22 +01:00
drivers spi: spi-geni-qcom: Fix geni_spi_isr() NULL dereference in timeout case 2021-01-17 14:17:00 +01:00
fs fanotify: Fix sys_fanotify_mark() on native x86-32 2021-01-17 14:16:59 +01:00
include fanotify: Fix sys_fanotify_mark() on native x86-32 2021-01-17 14:16:59 +01:00
init exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel workqueue: Kick a worker based on the actual activation of delayed works 2021-01-12 20:18:14 +01:00
lib lib/genalloc: fix the overflow when size is too big 2021-01-12 20:18:16 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: make wait_on_page_writeback() wait for multiple pending writebacks 2021-01-12 20:18:22 +01:00
net nexthop: Bounce NHA_GATEWAY in FDB nexthop groups 2021-01-17 14:16:57 +01:00
samples samples/bpf: Fix possible hang in xdpsock with multiple threads 2020-12-30 11:53:49 +01:00
scripts depmod: handle the case of /sbin/depmod without /sbin in PATH 2021-01-12 20:18:16 +01:00
security ima: Don't modify file descriptor mode on the fly 2020-12-30 11:54:17 +01:00
sound ALSA: hda/realtek: Add two "Intel Reference board" SSID in the ALC256. 2021-01-12 20:18:24 +01:00
tools selftests/bpf: Clarify build error if no vmlinux 2021-01-17 14:17:00 +01:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: check tlbs_dirty directly 2021-01-12 20:18:22 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-10 15:30:13 -08:00
Makefile Linux 5.10.7 2021-01-12 20:18:27 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.