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Daniel Vetter a67a88b0b8 s390/pci: remove races against pte updates
Way back it was a reasonable assumptions that iomem mappings never
change the pfn range they point at. But this has changed:

- gpu drivers dynamically manage their memory nowadays, invalidating
ptes with unmap_mapping_range when buffers get moved

- contiguous dma allocations have moved from dedicated carvetouts to
cma regions. This means if we miss the unmap the pfn might contain
pagecache or anon memory (well anything allocated with GFP_MOVEABLE)

- even /dev/mem now invalidates mappings when the kernel requests that
iomem region when CONFIG_IO_STRICT_DEVMEM is set, see
commit 3234ac664a ("/dev/mem: Revoke mappings when a driver claims the
region")

Accessing pfns obtained from ptes without holding all the locks is
therefore no longer a good idea. Fix this.

Since zpci_memcpy_from|toio seems to not do anything nefarious with
locks we just need to open code get_pfn and follow_pfn and make sure
we drop the locks only after we're done. The write function also needs
the copy_from_user move, since we can't take userspace faults while
holding the mmap sem.

Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-11-09 11:21:00 +01:00
arch s390/pci: remove races against pte updates 2020-11-09 11:21:00 +01:00
block blk-mq: mark flush request as IDLE in flush_end_io() 2020-10-30 08:33:49 -06:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
Documentation Driver core documentation fixes for 5.10-rc3 2020-11-08 11:30:25 -08:00
drivers TTY/Serial fixes for 5.10-rc3 2020-11-08 11:28:08 -08:00
fs Fixes for 5.10-rc3: 2020-11-08 10:23:07 -08:00
include Fixes for 5.10-rc3: 2020-11-08 10:23:07 -08:00
init linux-kselftest-kunit-5.10-rc1 2020-10-18 14:45:59 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent 2020-11-08 11:18:39 -08:00
lib s390/kasan: remove 3-level paging support 2020-11-09 11:20:58 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/truncate.c: make __invalidate_mapping_pages() static 2020-11-02 12:14:19 -08:00
net Networking fixes for 5.10-rc3, including fixes from wireless, can, 2020-11-06 11:50:28 -08:00
samples misc: mic: remove the MIC drivers 2020-10-28 19:12:03 +01:00
scripts Driver core documentation fixes for 5.10-rc3 2020-11-08 11:30:25 -08:00
security ima: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
sound ASoC: Fixes for v5.10 2020-11-05 18:19:32 +01:00
tools linux-kselftest-fixes-5.10-rc3 2020-11-06 15:42:42 -08:00
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: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.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 MAINTAINERS: jarkko.sakkinen@linux.intel.com -> jarkko@kernel.org 2020-10-16 11:11:19 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Sangbeom Kim to credits 2020-10-26 10:11:18 +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 branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2020-11-07 11:24:03 -08:00
Makefile Linux 5.10-rc3 2020-11-08 16:10:16 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.