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
..
appldata	s390/appldata: use struct_size() helper	2020-06-29 16:32:34 +02:00
boot	s390/early: rewrite program parameter setup in C	2020-11-09 11:21:00 +01:00
configs	s390: update defconfigs	2020-11-03 15:12:16 +01:00
crypto	mm, treewide: rename kzfree() to kfree_sensitive()	2020-08-07 11:33:22 -07:00
hypfs	fs_parse: fold fs_parameter_desc/fs_parameter_spec	2020-02-07 14:48:37 -05:00
include	s390/kasan: move memory needs estimation into a function	2020-11-09 11:20:59 +01:00
kernel	s390/early: rewrite program parameter setup in C	2020-11-09 11:21:00 +01:00
kvm	mm/gup: remove task_struct pointer for all gup code	2020-08-12 10:58:04 -07:00
lib	s390/udelay: make it work for the early code	2020-11-09 11:20:58 +01:00
mm	s390/kasan: remove obvious parameter with the only possible value	2020-11-09 11:20:59 +01:00
net	s390/bpf: Fix multiple tail calls	2020-09-14 18:21:31 -07:00
oprofile	s390/unwind: introduce stack unwind API	2019-05-02 13:54:11 +02:00
pci	s390/pci: remove races against pte updates	2020-11-09 11:21:00 +01:00
purgatory	.gitignore: add SPDX License Identifier	2020-03-25 11:50:48 +01:00
tools	.gitignore: add SPDX License Identifier	2020-03-25 11:50:48 +01:00
Kbuild	s390/numa: move code to arch/s390/kernel	2020-08-11 18:16:55 +02:00
Kconfig	s390/kasan: remove 3-level paging support	2020-11-09 11:20:58 +01:00
Kconfig.debug	s390/mm,ptdump: convert to generic page table dumper	2020-09-14 11:38:34 +02:00
Makefile	kbuild: remove cc-option test of -ffreestanding	2020-07-07 11:13:10 +09:00