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Filename Latest commit message Latest commit date
Michael Ellerman 0b4eb172cc powerpc/64s: Fix crashes when toggling entry flush barrier
commit aec86b052df6541cc97c5fca44e5934cbea4963b upstream.

The entry flush mitigation can be enabled/disabled at runtime via a
debugfs file (entry_flush), which causes the kernel to patch itself to
enable/disable the relevant mitigations.

However depending on which mitigation we're using, it may not be safe to
do that patching while other CPUs are active. For example the following
crash:

  sleeper[15639]: segfault (11) at c000000000004c20 nip c000000000004c20 lr c000000000004c20

Shows that we returned to userspace with a corrupted LR that points into
the kernel, due to executing the partially patched call to the fallback
entry flush (ie. we missed the LR restore).

Fix it by doing the patching under stop machine. The CPUs that aren't
doing the patching will be spinning in the core of the stop machine
logic. That is currently sufficient for our purposes, because none of
the patching we do is to that code or anywhere in the vicinity.

Fixes: f79643787e0a ("powerpc/64s: flush L1D on kernel entry")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210506044959.1298123-2-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-19 10:08:29 +02:00
arch powerpc/64s: Fix crashes when toggling entry flush barrier 2021-05-19 10:08:29 +02:00
block block: only update parent bi_status when bio fail 2021-04-16 11:46:38 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation dt-bindings: net: ethernet-controller: fix typo in NVMEM 2021-04-14 08:24:18 +02:00
drivers i40e: Fix PHY type identifiers for 2.5G and 5G adapters 2021-05-19 10:08:28 +02:00
fs ceph: fix inode leak on getattr error in __fh_to_dentry 2021-05-19 10:08:26 +02:00
include netfilter: xt_SECMARK: add new revision to fix structure layout 2021-05-19 10:08:27 +02:00
init init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM 2021-04-10 13:34:32 +02:00
ipc
kernel kernel: kexec_file: fix error return code of kexec_calculate_store_digests() 2021-05-19 10:08:28 +02:00
lib net: fix nla_strcmp to handle more then one trailing null character 2021-05-19 10:08:27 +02:00
LICENSES
mm ksm: fix potential missing rmap_item for stable_node 2021-05-19 10:08:27 +02:00
net netfilter: nftables: avoid overflows in nft_hash_buckets() 2021-05-19 10:08:28 +02:00
samples samples/bpf: Fix broken tracex1 due to kprobe argument change 2021-05-19 10:08:23 +02:00
scripts kconfig: nconf: stop endless search loops 2021-05-19 10:08:23 +02:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-11 14:04:16 +02:00
sound ASoC: rt286: Make RT286_SET_GPIO_* readable and writable 2021-05-19 10:08:24 +02:00
tools selftests: Set CC to clang in lib.mk if LLVM is set 2021-05-19 10:08:22 +02:00
usr
virt KVM: Stop looking for coalesced MMIO zones if the bus is destroyed 2021-05-14 09:44:15 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.119 2021-05-14 09:44:33 +02:00
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.