While raising the gcc version requirement to 4.9, the compile-time check
in the unroll macro was accidentally changed from being used on gcc and
clang to being used on clang only.
Restore the gcc check, changing it from "gcc >= 4.7" to "all gcc".
[ We should probably remove this all entirely: if we remove the check
for CLANG, then the check for GCC can go away. Older versions of clang
are not really appropriate or supported for kernel builds - Linus ]
Fixes: 6ec4476ac8 ("Raise gcc version requirement to 4.9")
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.eti.br>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull device mapper fixes from Mike Snitzer:
- A request-based DM fix to not use a waitqueue to wait for blk-mq IO
completion because doing so is racey.
- A couple more DM zoned target fixes to address issues introduced
during the 5.8 cycle.
- A DM core fix to use proper interface to cleanup DM's static flush
bio.
- A DM core fix to prevent mm recursion during memory allocation needed
by dm_kobject_uevent.
* tag 'for-5.8/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm: use noio when sending kobject event
dm zoned: Fix zone reclaim trigger
dm zoned: fix unused but set variable warnings
dm writecache: reject asynchronous pmem devices
dm: use bio_uninit instead of bio_disassociate_blkg
dm: do not use waitqueue for request-based DM
Pull kallsyms fix from Kees Cook:
"Refactor kallsyms_show_value() users for correct cred.
I'm not delighted by the timing of getting these changes to you, but
it does fix a handful of kernel address exposures, and no one has
screamed yet at the patches.
Several users of kallsyms_show_value() were performing checks not
during "open". Refactor everything needed to gain proper checks
against file->f_cred for modules, kprobes, and bpf"
* tag 'kallsyms_show_value-v5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
selftests: kmod: Add module address visibility test
bpf: Check correct cred for CAP_SYSLOG in bpf_dump_raw_ok()
kprobes: Do not expose probe addresses to non-CAP_SYSLOG
module: Do not expose section addresses to non-CAP_SYSLOG
module: Refactor section attr into bin attribute
kallsyms: Refactor kallsyms_show_value() to take cred
Make sure we don't regress the CAP_SYSLOG behavior of the module address
visibility via /proc/modules nor /sys/module/*/sections/*.
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
When evaluating access control over kallsyms visibility, credentials at
open() time need to be used, not the "current" creds (though in BPF's
case, this has likely always been the same). Plumb access to associated
file->f_cred down through bpf_dump_raw_ok() and its callers now that
kallsysm_show_value() has been refactored to take struct cred.
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: bpf@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 7105e828c0 ("bpf: allow for correlation of maps and helpers in dump")
Signed-off-by: Kees Cook <keescook@chromium.org>
The kprobe show() functions were using "current"'s creds instead
of the file opener's creds for kallsyms visibility. Fix to use
seq_file->file->f_cred.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 81365a947d ("kprobes: Show address of kprobes if kallsyms does")
Fixes: ffb9bd68eb ("kprobes: Show blacklist addresses as same as kallsyms does")
Signed-off-by: Kees Cook <keescook@chromium.org>
In order to gain access to the open file's f_cred for kallsym visibility
permission checks, refactor the module section attributes to use the
bin_attribute instead of attribute interface. Additionally removes the
redundant "name" struct member.
Cc: stable@vger.kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
In order to perform future tests against the cred saved during open(),
switch kallsyms_show_value() to operate on a cred, and have all current
callers pass current_cred(). This makes it very obvious where callers
are checking the wrong credential in their "read" contexts. These will
be fixed in the coming patches.
Additionally switch return value to bool, since it is always used as a
direct permission check, not a 0-on-success, negative-on-error style
function return.
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Update Documentation for the gcc v4.9 upgrade requirement.
Fixes: 5429ef62bc ("compiler/gcc: Raise minimum GCC version for kernel builds to 4.8")
Fixes: 6ec4476ac8 ("Raise gcc version requirement to 4.9")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull sound fixes from Takashi Iwai:
"A collection of small, mostly device-specific fixes.
The significant one is the regression fix for USB-audio implicit
feedback devices due to the incorrect frame size calculation, which
landed in 5.8 and stable trees.
In addition, a few usual HD-audio and USB-audio quirks, Intel HDMI
fixes, ASoC fsl and rt5682 fixes, as well as the fix in
compress-offload partial drain operation"
* tag 'sound-5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: compress: fix partial_drain completion state
ALSA: usb-audio: Add implicit feedback quirk for RTX6001
ALSA: usb-audio: add quirk for MacroSilicon MS2109
ALSA: hda/realtek: Enable headset mic of Acer Veriton N4660G with ALC269VC
ALSA: hda/realtek: Enable headset mic of Acer C20-820 with ALC269VC
ALSA: hda/realtek - Enable audio jacks of Acer vCopperbox with ALC269VC
ALSA: hda/realtek - Fix Lenovo Thinkpad X1 Carbon 7th quirk subdevice id
ALSA: hda/hdmi: improve debug traces for stream lookups
ALSA: hda/hdmi: fix failures at PCM open on Intel ICL and later
ALSA: opl3: fix infoleak in opl3
ALSA: usb-audio: Replace s/frame/packet/ where appropriate
ALSA: usb-audio: Fix packet size calculation
AsoC: amd: add missing snd- module prefix to the acp3x-rn driver kernel module
ALSA: hda - let hs_mic be picked ahead of hp_mic
ASoC: rt5682: fix the pop noise while OMTP type headset plugin
ASoC: fsl_mqs: Fix unchecked return value for clk_prepare_enable
ASoC: fsl_mqs: Don't check clock is NULL before calling clk API
I realize that we fairly recently raised it to 4.8, but the fact is, 4.9
is a much better minimum version to target.
We have a number of workarounds for actual bugs in pre-4.9 gcc versions
(including things like internal compiler errors on ARM), but we also
have some syntactic workarounds for lacking features.
In particular, raising the minimum to 4.9 means that we can now just
assume _Generic() exists, which is likely the much better replacement
for a lot of very convoluted built-time magic with conditionals on
sizeof and/or __builtin_choose_expr() with same_type() etc.
Using _Generic also means that you will need to have a very recent
version of 'sparse', but thats easy to build yourself, and much less of
a hassle than some old gcc version can be.
The latest (in a long string) of reasons for minimum compiler version
upgrades was commit 5435f73d5c ("efi/x86: Fix build with gcc 4").
Ard points out that RHEL 7 uses gcc-4.8, but the people who stay back on
old RHEL versions persumably also don't build their own kernels anyway.
And maybe they should cross-built or just have a little side affair with
a newer compiler?
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Only triggering reclaim based on the percentage of unmapped cache
zones can fail to detect cases where reclaim is needed, e.g. if the
target has only 2 or 3 cache zones and only one unmapped cache zone,
the percentage of free cache zones is higher than
DMZ_RECLAIM_LOW_UNMAP_ZONES (30%) and reclaim does not trigger.
This problem, combined with the fact that dmz_schedule_reclaim() is
called from dmz_handle_bio() without the map lock held, leads to a
race between zone allocation and dmz_should_reclaim() result.
Depending on the workload applied, this race can lead to the write
path waiting forever for a free zone without reclaim being triggered.
Fix this by moving dmz_schedule_reclaim() inside dmz_alloc_zone()
under the map lock. This results in checking the need for zone reclaim
whenever a new data or buffer zone needs to be allocated.
Also fix dmz_reclaim_percentage() to always return 0 if the number of
unmapped cache (or random) zones is less than or equal to 1.
Suggested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fix unused but set variable warnings:
drivers/md/dm-zoned-reclaim.c:504:42: warning:
variable nr_rnd set but not used [-Wunused-but-set-variable]
504 | unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0;
| ^~~~~~
drivers/md/dm-zoned-reclaim.c:504:24: warning:
variable nr_unmap_rnd set but not used [-Wunused-but-set-variable]
504 | unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0;
| ^~~~~~~~~~~~
Fixes: f97809aec5 ("dm zoned: per-device reclaim")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
bio_uninit is the proper API to clean up a BIO that has been allocated
on stack or inside a structure that doesn't come from the BIO allocator.
Switch dm to use that instead of bio_disassociate_blkg, which really is
an implementation detail. Note that the bio_uninit calls are also moved
to the two callers of __send_empty_flush, so that they better pair with
the bio_init calls used to initialize them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pull perf tooling fixes from Arnaldo Carvalho de Melo:
- Intel PT fixes for PEBS-via-PT with registers
- Fixes for Intel PT python based GUI
- Avoid duplicated sideband events with Intel PT in system wide tracing
- Remove needless 'dummy' event from TUI menu, used when synthesizing
meta data events for pre-existing processes
- Fix corner case segfault when pressing enter in a screen without
entries in the TUI for report/top
- Fixes for time stamp handling in libtraceevent
- Explicitly set utf-8 encoding in perf flamegraph
- Update arch/x86/lib/memcpy_64.S copy used in 'perf bench mem memcpy',
silencing perf build warning
* tag 'perf-tools-fixes-2020-07-07' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf report TUI: Remove needless 'dummy' event from menu
perf intel-pt: Fix PEBS sample for XMM registers
perf intel-pt: Fix displaying PEBS-via-PT with registers
perf intel-pt: Fix recording PEBS-via-PT with registers
perf report TUI: Fix segmentation fault in perf_evsel__hists_browse()
tools lib traceevent: Add proper KBUFFER_TYPE_TIME_STAMP handling
tools lib traceevent: Add API to read time information from kbuffer
perf scripts python: exported-sql-viewer.py: Fix time chart call tree
perf scripts python: exported-sql-viewer.py: Fix zero id in call tree 'Find' result
perf scripts python: exported-sql-viewer.py: Fix zero id in call graph 'Find' result
perf scripts python: exported-sql-viewer.py: Fix unexpanded 'Find' result
perf record: Fix duplicated sideband events with Intel PT system wide tracing
perf scripts python: export-to-postgresql.py: Fix struct.pack() int argument
tools arch: Update arch/x86/lib/memcpy_64.S copy used in 'perf bench mem memcpy'
perf flamegraph: Explicitly set utf-8 encoding
Pull MTD fixes from Miquel Raynal:
"MTD:
- Set a missing master partition panic write flag
Raw NAND:
- Fix build issue in the xway driver
- Fix a wrong return code"
* tag 'mtd/fixes-for-5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux:
mtd: rawnand: xway: Fix build issue
mtd: set master partition panic write flag
nandsim: Fix return code testing of ns_find_operation()
Pull btrfs fixes from David Sterba:
- regression fix of a leak in global block reserve accounting
- fix a (hard to hit) race of readahead vs releasepage that could lead
to crash
- convert all remaining uses of comment fall through annotations to the
pseudo keyword
- fix crash when mounting a fuzzed image with -o recovery
* tag 'for-5.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: reset tree root pointer after error in init_tree_roots
btrfs: fix reclaim_size counter leak after stealing from global reserve
btrfs: fix fatal extent_buffer readahead vs releasepage race
btrfs: convert comments to fallthrough annotations
Pull tpm fix from Jarkko Sakkinen:
"Revert commit e918e57041 ("tpm_tis: Remove the HID IFX0102").
Removing IFX0102 from tpm_tis was not a right move because both
tpm_tis and tpm_infineon use the same device ID.
A real fix requires quirks added to both drivers. It can probably wait
until v5.9 as the bug has existed since 2006"
* tag 'tpmdd-next-v5.8-rc5' of git://git.infradead.org/users/jjs/linux-tpmdd:
Revert commit e918e57041 ("tpm_tis: Remove the HID IFX0102")
This MIPS driver does not support COMPILE_TEST yet and failed to build
under my radar.
Replace 'mtd' chich is not defined in the scope of xway_nand_remove()
by nand_to_mtd(chip). The mistake has been added in the long series
dropping nand_release().
Tested with a 7.3.0 MIPS GCC toolchain built with Buildroot.
Fixes: 9fdd78f7bc ("mtd: rawnand: xway: Stop using nand_release()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200626065511.16424-1-miquel.raynal@bootlin.com
Given request-based DM now uses blk-mq's blk_mq_queue_inflight() to
determine if outstanding IO has completed (and DM has no control over
the blk-mq state machine used to track outstanding IO) it is unsafe to
wakeup waiter (dm_wait_for_completion) before blk-mq has cleared a
request's state bits (e.g. MQ_RQ_IN_FLIGHT or MQ_RQ_COMPLETE). As
such dm_wait_for_completion() could be left to wait indefinitely if no
other requests complete.
Fix this by eliminating request-based DM's use of waitqueue to wait
for blk-mq requests to complete in dm_wait_for_completion.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Depends-on: 3c94d83cb3 ("blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
When HDMI PCM devices are opened in a specific order, with at least one
HDMI/DP receiver connected, ALSA PCM open fails to -EBUSY on the
connected monitor, on recent Intel platforms (ICL/JSL and newer). While
this is not a typical sequence, at least Pulseaudio does this every time
when it is started, to discover the available PCMs.
The rootcause is an invalid assumption in hdmi_add_pin(), where the
total number of converters is assumed to be known at the time the
function is called. On older Intel platforms this held true, but after
ICL/JSL, the order how pins and converters are in the subnode list as
returned by snd_hda_get_sub_nodes(), was changed. As a result,
information for some converters was not stored to per_pin->mux_nids.
And this means some pins cannot be connected to all converters, and
application instead gets -EBUSY instead at open.
The assumption that converters are always before pins in the subnode
list, is not really a valid one. Fix the problem in hdmi_parse_codec()
by introducing separate loops for discovering converters and pins.
BugLink: https://github.com/thesofproject/linux/issues/1978
BugLink: https://github.com/thesofproject/linux/issues/2216
BugLink: https://github.com/thesofproject/linux/issues/2217
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200703153818.2808592-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Removing IFX0102 from tpm_tis was not a right move because both tpm_tis
and tpm_infineon use the same device ID. Revert the commit and add a
remark about a bug caused by commit 93e1b7d42e ("[PATCH] tpm: add HID
module parameter").
Fixes: e918e57041 ("tpm_tis: Remove the HID IFX0102")
Reported-by: Peter Huewe <peterhuewe@gmx.de>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Pull kvm fixes from Paolo Bonzini:
"Bugfixes and a one-liner patch to silence a sparse warning"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: arm64: Stop clobbering x0 for HVC_SOFT_RESTART
KVM: arm64: PMU: Fix per-CPU access in preemptible context
KVM: VMX: Use KVM_POSSIBLE_CR*_GUEST_BITS to initialize guest/host masks
KVM: x86: Mark CR4.TSD as being possibly owned by the guest
KVM: x86: Inject #GP if guest attempts to toggle CR4.LA57 in 64-bit mode
kvm: use more precise cast and do not drop __user
KVM: x86: bit 8 of non-leaf PDPEs is not reserved
KVM: X86: Fix async pf caused null-ptr-deref
KVM: arm64: vgic-v4: Plug race between non-residency and v4.1 doorbell
KVM: arm64: pvtime: Ensure task delay accounting is enabled
KVM: arm64: Fix kvm_reset_vcpu() return code being incorrect with SVE
KVM: arm64: Annotate hyp NMI-related functions as __always_inline
KVM: s390: reduce number of IO pins to 1
Pull s390 fixes from Heiko Carstens:
- Initialize jump labels before early command line parsing in order to
make init_on_alloc and init_on_free options work
- Fix vfio-ccw build error due to missing include
- Prevent callchain data collection with hardware sampling, since the
callchains simply do not exist
- Prevent multiple registrations of the same zPCI function
- Update defconfigs
* tag 's390-5.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
vfio-ccw: Fix a build error due to missing include of linux/slab.h
s390: update defconfigs
s390/cpum_sf: prohibit callchain data collection
s390/setup: init jump labels before command line parsing
s390/maccess: add no DAT mode to kernel_write
s390/pci: fix enabling a reserved PCI function
KVM/arm fixes for 5.8, take #3
- Disable preemption on context-switching PMU EL0 state happening
on system register trap
- Don't clobber X0 when tearing down KVM via a soft reset (kexec)
Fixing the common case of:
perf record
perf report
And getting just the cycles events.
We now have a 'dummy' event to get perf metadata events that take place
while we synthesize metadata records for pre-existing processes by
traversing procfs, so we always have this extra 'dummy' evsel, but we
don't have to offer it as there will be no samples on it, remove this
distraction.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/20200706115452.GA2772@redhat.com/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
After recording PEBS-via-PT, perf script will not accept 'iregs' field e.g.
# perf record -c 10000 -e '{intel_pt/branch=0/,branch-loads/aux-output/ppp}' -I -- ls -l
...
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data ]
# ./perf script --itrace=eop -F+iregs
Samples for 'dummy:u' event do not have IREGS attribute set. Cannot print 'iregs' field.
Fix by using allow_user_set, which is true when recording AUX area data.
Fixes: 9e64cefe43 ("perf intel-pt: Process options for PEBS event synthesis")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Luwei Kang <luwei.kang@intel.com>
Link: http://lore.kernel.org/lkml/20200630133935.11150-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When recording PEBS-via-PT, the kernel will not accept the intel_pt
event with register sampling e.g.
# perf record --kcore -c 10000 -e '{intel_pt/branch=0/,branch-loads/aux-output/ppp}' -I -- ls -l
Error:
intel_pt/branch=0/: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
Fix by suppressing register sampling on the intel_pt evsel.
Committer notes:
Adrian informed that this is only available from Tremont onwards, so on
older processors the error continues the same as before.
Fixes: 9e64cefe43 ("perf intel-pt: Process options for PEBS event synthesis")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Luwei Kang <luwei.kang@intel.com>
Link: http://lore.kernel.org/lkml/20200630133935.11150-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Commit 07da1ffaa1 ("KVM: arm64: Remove host_cpu_context
member from vcpu structure") has, by removing the host CPU
context pointer, exposed that kvm_vcpu_pmu_restore_guest
is called in preemptible contexts:
[ 266.932442] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-aar/779
[ 266.939721] caller is debug_smp_processor_id+0x20/0x30
[ 266.944157] CPU: 2 PID: 779 Comm: qemu-system-aar Tainted: G E 5.8.0-rc3-00015-g8d4aa58b2fe3 #1374
[ 266.954268] Hardware name: amlogic w400/w400, BIOS 2020.04 05/22/2020
[ 266.960640] Call trace:
[ 266.963064] dump_backtrace+0x0/0x1e0
[ 266.966679] show_stack+0x20/0x30
[ 266.969959] dump_stack+0xe4/0x154
[ 266.973338] check_preemption_disabled+0xf8/0x108
[ 266.977978] debug_smp_processor_id+0x20/0x30
[ 266.982307] kvm_vcpu_pmu_restore_guest+0x2c/0x68
[ 266.986949] access_pmcr+0xf8/0x128
[ 266.990399] perform_access+0x8c/0x250
[ 266.994108] kvm_handle_sys_reg+0x10c/0x2f8
[ 266.998247] handle_exit+0x78/0x200
[ 267.001697] kvm_arch_vcpu_ioctl_run+0x2ac/0xab8
Note that the bug was always there, it is only the switch to
using percpu accessors that made it obvious.
The fix is to wrap these accesses in a preempt-disabled section,
so that we sample a coherent context on trap from the guest.
Fixes: 435e53fb5e ("arm64: KVM: Enable VHE support for :G/:H perf event modifiers")
Cc:: Andrew Murray <amurray@thegoodpenguin.co.uk>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Using a mutex for "print this warning only once" is so overdesigned as
to be actively offensive to my sensitive stomach.
Just use "pr_info_once()" that already does this, although in a
(harmlessly) racy manner that can in theory cause the message to be
printed twice if more than one CPU races on that "is this the first
time" test.
[ If somebody really cares about that harmless data race (which sounds
very unlikely indeed), that person can trivially fix printk_once() by
using a simple atomic access, preferably with an optimistic non-atomic
test first before even bothering to treat the pointless "make sure it
is _really_ just once" case.
A mutex is most definitely never the right primitive to use for
something like this. ]
Yes, this is a small and meaningless detail in a code path that hardly
matters. But let's keep some code quality standards here, and not
accept outrageously bad code.
Link: https://lore.kernel.org/lkml/CAHk-=wgV9toS7GU3KmNpj8hCS9SeF+A0voHS8F275_mgLhL4Lw@mail.gmail.com/
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 fixes from Thomas Gleixner:
"A series of fixes for x86:
- Reset MXCSR in kernel_fpu_begin() to prevent using a stale user
space value.
- Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly
whitelisted for split lock detection. Some CPUs which do not
support it crash even when the MSR is written to 0 which is the
default value.
- Fix the XEN PV fallout of the entry code rework
- Fix the 32bit fallout of the entry code rework
- Add more selftests to ensure that these entry problems don't come
back.
- Disable 16 bit segments on XEN PV. It's not supported because XEN
PV does not implement ESPFIX64"
* tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/ldt: Disable 16-bit segments on Xen PV
x86/entry/32: Fix #MC and #DB wiring on x86_32
x86/entry/xen: Route #DB correctly on Xen PV
x86/entry, selftests: Further improve user entry sanity checks
x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER
selftests/x86: Consolidate and fix get/set_eflags() helpers
selftests/x86/syscall_nt: Clear weird flags after each test
selftests/x86/syscall_nt: Add more flag combinations
x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C
x86/entry: Assert that syscalls are on the right stack
x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted
x86/fpu: Reset MXCSR to default in kernel_fpu_begin()
Pull irq fixes from Thomas Gleixner:
"A set of interrupt chip driver fixes:
- Ensure the atomicity of affinity updates in the GIC driver
- Don't try to sleep in atomic context when waiting for the GICv4.1
to respond. Use polling instead.
- Typo fixes in Kconfig and warnings"
* tag 'irq-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/gic: Atomically update affinity
irqchip/riscv-intc: Fix a typo in a pr_warn()
irqchip/gic-v4.1: Use readx_poll_timeout_atomic() to fix sleep in atomic
irqchip/loongson-pci-msi: Fix a typo in Kconfig
