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Yash Shah db9138d06e RISC-V: Don't allow write+exec only page mapping request in mmap 
[ Upstream commit e0d17c842c ]

As per the table 4.4 of version "20190608-Priv-MSU-Ratified" of the
RISC-V instruction set manual[0], the PTE permission bit combination of
"write+exec only" is reserved for future use. Hence, don't allow such
mapping request in mmap call.

An issue is been reported by David Abdurachmanov, that while running
stress-ng with "sysbadaddr" argument, RCU stalls are observed on RISC-V
specific kernel.

This issue arises when the stress-sysbadaddr request for pages with
"write+exec only" permission bits and then passes the address obtain
from this mmap call to various system call. For the riscv kernel, the
mmap call should fail for this particular combination of permission bits
since it's not valid.

[0]: http://dabbelt.com/~palmer/keep/riscv-isa-manual/riscv-privileged-20190608-1.pdf

Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reported-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
[Palmer: Refer to the latest ISA specification at the only link I could
find, and update the terminology.]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-30 23:17:15 -04:00
arch RISC-V: Don't allow write+exec only page mapping request in mmap 2020-06-30 23:17:15 -04:00
block block/bio-integrity: don't free 'buf' if bio_integrity_add_page() failed 2020-06-30 23:17:00 -04:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: algboss - don't wait during notifier callback 2020-06-25 15:33:09 +02:00
Documentation mtd: rawnand: Pass a nand_chip object to nand_release() 2020-06-25 15:33:08 +02:00
drivers net: alx: fix race condition in alx_remove 2020-06-30 23:17:14 -04:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs cifs/smb3: Fix data inconsistent when zero file range 2020-06-30 23:17:09 -04:00
include net: qed: fix left elements count calculation 2020-06-30 23:17:12 -04:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:18:49 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:18:40 +02:00
kernel blktrace: break out of blktrace setup on concurrent calls 2020-06-30 23:17:15 -04:00
lib lib/zlib: remove outdated and incorrect pre-increment optimization 2020-06-25 15:33:02 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm: initialize deferred pages with interrupts enabled 2020-06-22 09:05:21 +02:00
net netfilter: ipset: fix unaligned atomic access 2020-06-30 23:17:12 -04:00
samples samples: bpf: Fix build error 2020-06-03 08:19:31 +02:00
scripts kbuild: improve cc-option to clean up all temporary files 2020-06-30 23:17:15 -04:00
security apparmor: don't try to replace stale label in ptraceme check 2020-06-30 23:17:03 -04:00
sound ASoC: rockchip: Fix a reference count leak. 2020-06-30 23:17:11 -04:00
tools perf report: Fix NULL pointer dereference in hists__fprintf_nr_sample_events() 2020-06-25 15:33:05 +02:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception 2020-06-22 09:05:09 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 16:38:49 +01:00
Makefile Linux 4.19.130 2020-06-25 15:33:11 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
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.