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Dave Hansen 58fa4b36ab selftests/vm/pkeys: refill shadow register after implicit kernel write 
[ Upstream commit 6039ca2549 ]

The pkey test code keeps a "shadow" of the pkey register around.  This
ensures that any bugs which might write to the register can be caught more
quickly.

Generally, userspace has a good idea when the kernel is going to write to
the register.  For instance, alloc_pkey() is passed a permission mask.
The caller of alloc_pkey() can update the shadow based on the return value
and the mask.

But, the kernel can also modify the pkey register in a more sneaky way.
For mprotect(PROT_EXEC) mappings, the kernel will allocate a pkey and
write the pkey register to create an execute-only mapping.  The kernel
never tells userspace what key it uses for this.

This can cause the test to fail with messages like:

	protection_keys_64.2: pkey-helpers.h:132: _read_pkey_reg: Assertion `pkey_reg == shadow_pkey_reg' failed.

because the shadow was not updated with the new kernel-set value.

Forcibly update the shadow value immediately after an mprotect().

Link: https://lkml.kernel.org/r/20210611164200.EF76AB73@viggo.jf.intel.com
Fixes: 6af17cf89e ("x86/pkeys/selftests: Add PROT_EXEC test")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "Desnes A. Nunes do Rosario" <desnesn@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2021-07-14 16:56:52 +02:00
arch arm64: dts: marvell: armada-37xx: Fix reg for standard variant of UART 2021-07-14 16:56:50 +02:00
block blk-mq: update hctx->dispatch_busy in case of real scheduler 2021-07-14 16:56:13 +02:00
certs certs: Add ability to preload revocation certs 2021-06-30 08:47:30 -04:00
crypto crypto: sm2 - fix a memory leak in sm2 2021-07-14 16:56:06 +02:00
Documentation powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable 2021-07-14 16:56:49 +02:00
drivers vfio/pci: Handle concurrent vma faults 2021-07-14 16:56:50 +02:00
fs mm/huge_memory.c: add missing read-only THP checking in transparent_hugepage_enabled() 2021-07-14 16:56:50 +02:00
include include/linux/huge_mm.h: remove extern keyword 2021-07-14 16:56:51 +02:00
init sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel rcu: Invoke rcu_spawn_core_kthreads() from rcu_spawn_gp_kthread() 2021-07-14 16:56:33 +02:00
lib lib/math/rational.c: fix divide by zero 2021-07-14 16:56:51 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/z3fold: use release_z3fold_page_locked() to release locked z3fold page 2021-07-14 16:56:51 +02:00
net net: tipc: fix FB_MTU eat two pages 2021-07-14 16:56:32 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:56:23 +02:00
scripts kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_<obj> := n' 2021-07-14 16:56:04 +02:00
security evm: fix writing <securityfs>/evm overflow 2021-07-14 16:56:04 +02:00
sound ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found 2021-07-14 16:56:49 +02:00
tools selftests/vm/pkeys: refill shadow register after implicit kernel write 2021-07-14 16:56:52 +02:00
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: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:25 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.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 f2fs: move ioctl interface definitions to separated file 2021-05-19 10:13:00 +02:00
Makefile Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 16:55:53 +02:00
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.