These symbol patterns were whitelisted to allow them to reference to
functions with the old __devinit and __devexit annotations.
We stopped doing this a long time ago, for example, commit 6f03979051
("Drivers: scsi: remove __dev* attributes.") remove those annotations
from the scsi drivers.
Keep *_ops, *_probe, and *_console, otherwise they will really cause
section mismatch warnings.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Drivers must not reference .meminit* sections, which are discarded
when CONFIG_MEMORY_HOTPLUG=n.
The reason for whitelisting "*driver" in the section mismatch check
was to allow drivers to reference symbols annotated as __devinit or
__devexit that existed in the past.
Those annotations were removed by the following commits:
- 54b956b903 ("Remove __dev* markings from init.h")
- 92e9e6d1f9 ("modpost.c: Stop checking __dev* section mismatches")
Remove the stale whitelist.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
We have never used __memexit, __memexitdata, or __memexitconst.
These were unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
scripts/pahole-flags.sh is executed so many times.
You can confirm it, as follows:
$ cat <<EOF >> scripts/pahole-flags.sh
> echo "scripts/pahole-flags.sh was executed" >&2
> EOF
$ make -s
scripts/pahole-flags.sh was executed
scripts/pahole-flags.sh was executed
scripts/pahole-flags.sh was executed
scripts/pahole-flags.sh was executed
scripts/pahole-flags.sh was executed
[ lots of repeated lines... ]
This scripts is executed more than 20 times during the kernel build
because PAHOLE_FLAGS is a recursively expanded variable and exported
to sub-processes.
With GNU Make >= 4.4, it is executed more than 60 times because
exported variables are also passed to other $(shell ) invocations.
Without careful coding, it is known to cause an exponential fork
explosion. [1]
The use of $(shell ) in an exported recursive variable is likely wrong
because $(shell ) is always evaluated due to the 'export' keyword, and
the evaluation can occur multiple times by the nature of recursive
variables.
Convert the shell script to a Makefile, which is included only when
CONFIG_DEBUG_INFO_BTF=y.
[1]: https://savannah.gnu.org/bugs/index.php?64746
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
The '%.ko' rule in arch/*/Makefile.postlink does nothing but call the
'true' command.
Remove the unneeded code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Now that vdso_install does not depend on any in-tree build artifact,
it no longer needs a compiler, making no-compiler-targets the same
as no-sync-config-targets.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Currently, there is no standard implementation for vdso_install,
leading to various issues:
1. Code duplication
Many architectures duplicate similar code just for copying files
to the install destination.
Some architectures (arm, sparc, x86) create build-id symlinks,
introducing more code duplication.
2. Unintended updates of in-tree build artifacts
The vdso_install rule depends on the vdso files to install.
It may update in-tree build artifacts. This can be problematic,
as explained in commit 19514fc665 ("arm, kbuild: make
"make install" not depend on vmlinux").
3. Broken code in some architectures
Makefile code is often copied from one architecture to another
without proper adaptation.
'make vdso_install' for parisc does not work.
'make vdso_install' for s390 installs vdso64, but not vdso32.
To address these problems, this commit introduces a generic vdso_install
rule.
Architectures that support vdso_install need to define vdso-install-y
in arch/*/Makefile. vdso-install-y lists the files to install.
For example, arch/x86/Makefile looks like this:
vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg
vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg
vdso-install-$(CONFIG_X86_32) += arch/x86/entry/vdso/vdso32.so.dbg
vdso-install-$(CONFIG_IA32_EMULATION) += arch/x86/entry/vdso/vdso32.so.dbg
These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix,
if exists, stripped away.
vdso-install-y can optionally take the second field after the colon
separator. This is needed because some architectures install a vdso
file as a different base name.
The following is a snippet from arch/arm64/Makefile.
vdso-install-$(CONFIG_COMPAT_VDSO) += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so
This will rename vdso.so.dbg to vdso32.so during installation. If such
architectures change their implementation so that the base names match,
this workaround will go away.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Guo Ren <guoren@kernel.org>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
The documentation for kbuild and makefiles is missing an explanation of
a variable important for some architectures.
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
You cannot run this code because arch/um/Makefile does not define the
vdso_install target.
It appears that this code was blindly copied from another architecture.
Remove the dead code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Richard Weinberger <richard@nod.at>
You cannot run this code because arch/csky/Makefile does not define the
vdso_install target.
It appears that this code was blindly copied from another architecture.
Remove the dead code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Guo Ren <guoren@kernel.org>
The first few lines of section_rel() and section_rela() are the same.
They both retrieve the index of the section to which the relocaton
applies, and skip known-good sections. This common code should be moved
to check_sec_ref().
Avoid ugly casts when computing 'start' and 'stop', and also make the
Elf_Rel and Elf_Rela pointers const.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
We can replace &elf->sechdrs[i] with &sechdrs[i] to slightly shorten
the code because we already have the local variable 'sechdrs'.
However, defining 'sechdr' instead shortens the code further.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
The current TO_NATIVE() has some limitations:
1) You cannot cast the argument.
2) You cannot pass a variable marked as 'const'.
3) Passing an array is a bug, but it is not detected.
Impelement TO_NATIVE() using bswap_*() functions. These are GNU
extensions. If we face portability issues, we can port the code from
include/uapi/linux/swab.h.
With this change, get_rel_type_and_sym() can be simplified by casting
the arguments directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
When MODULE_DEVICE_TABLE(ishtp, ) is built on a host with a different
endianness from the target architecture, it results in an incorrect
MODULE_ALIAS().
For example, see a case where drivers/platform/x86/intel/ishtp_eclite.c
is built as a module for x86.
If you build it on a little-endian host, you will get the correct
MODULE_ALIAS:
$ grep MODULE_ALIAS drivers/platform/x86/intel/ishtp_eclite.mod.c
MODULE_ALIAS("ishtp:{6A19CC4B-D760-4DE3-B14D-F25EBD0FBCD9}");
However, if you build it on a big-endian host, you will get a wrong
MODULE_ALIAS:
$ grep MODULE_ALIAS drivers/platform/x86/intel/ishtp_eclite.mod.c
MODULE_ALIAS("ishtp:{BD0FBCD9-F25E-B14D-4DE3-D7606A19CC4B}");
This issue has been unnoticed because the x86 kernel is most likely built
natively on an x86 host.
The guid field must not be reversed because guid_t is an array of __u8.
Fixes: fa443bc3c1 ("HID: intel-ish-hid: add support for MODULE_DEVICE_TABLE()")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
When MODULE_DEVICE_TABLE(tee, ) is built on a host with a different
endianness from the target architecture, it results in an incorrect
MODULE_ALIAS().
For example, see a case where drivers/char/hw_random/optee-rng.c
is built as a module for ARM little-endian.
If you build it on a little-endian host, you will get the correct
MODULE_ALIAS:
$ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c
MODULE_ALIAS("tee:ab7a617c-b8e7-4d8f-8301-d09b61036b64*");
However, if you build it on a big-endian host, you will get a wrong
MODULE_ALIAS:
$ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c
MODULE_ALIAS("tee:646b0361-9bd0-0183-8f4d-e7b87c617aab*");
The same problem also occurs when you enable CONFIG_CPU_BIG_ENDIAN,
and build it on a little-endian host.
This issue has been unnoticed because the ARM kernel is configured for
little-endian by default, and most likely built on a little-endian host
(cross-build on x86 or native-build on ARM).
The uuid field must not be reversed because uuid_t is an array of __u8.
Fixes: 0fc1db9d10 ("tee: add bus driver framework for TEE based devices")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
The generation of the kernel-devel package is disabled for binrpm-pkg
presumably because it was quite big (>= 200MB) and took a long time to
package.
Commit fe66b5d2ae ("kbuild: refactor kernel-devel RPM package and
linux-headers Deb package") reduced the package size to 12MB, and now
it is quick to build. It won't hurt to have binrpm-pkg generate it by
default.
If you want to skip the kernel-devel package generation, you can pass
RPMOPTS='--without devel':
$ make binrpm-pkg RPMOPTS='--without devel'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
resulting in build failures in hermetic environments where `cc` does not
exist. This includes both hostprogs and proc-macros.
Since we are setting the linker to `HOSTCC`, we set the linker flavor to
`gcc` explicitly. The linker-flavor selects both which linker to search
for if the linker is unset, and which kind of linker flags to pass.
Without this flag, `rustc` would attempt to determine which flags to
pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
name of the linker-flavor used by `rustc` for all C compilers, including
both `gcc` and `clang`.
Signed-off-by: Matthew Maurer <mmaurer@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
kernel.spec is the last piece that resides outside the rpmbuild/
directory. Move all the RPM-related files to rpmbuild/ consistently.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Modify modpost to use binary search for converting addresses back
into symbol references. Previously it used linear search.
This change saves a few seconds of wall time for defconfig builds,
but can save several minutes on allyesconfigs.
Before:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
198.38user 1.27system 3:19.71elapsed
After:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
11.91user 0.85system 0:12.78elapsed
Signed-off-by: Jack Brennen <jbrennen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull Kbuild fixes from Masahiro Yamada:
- Fix the module compression with xz so the in-kernel decompressor
works
- Document a kconfig idiom to express an optional dependency between
modules
- Make modpost, when W=1 is given, detect broken drivers that reference
.exit.* sections
- Remove unused code
* tag 'kbuild-fixes-v6.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: remove stale code for 'source' symlink in packaging scripts
modpost: Don't let "driver"s reference .exit.*
vmlinux.lds.h: remove unused CPU_KEEP and CPU_DISCARD macros
modpost: add missing else to the "of" check
Documentation: kbuild: explain handling optional dependencies
kbuild: Use CRC32 and a 1MiB dictionary for XZ compressed modules
Pull misc fixes from Andrew Morton:
"Fourteen hotfixes, eleven of which are cc:stable. The remainder
pertain to issues which were introduced after 6.5"
* tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
Crash: add lock to serialize crash hotplug handling
selftests/mm: fix awk usage in charge_reserved_hugetlb.sh and hugetlb_reparenting_test.sh that may cause error
mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified
mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions()
mm, memcg: reconsider kmem.limit_in_bytes deprecation
mm: zswap: fix potential memory corruption on duplicate store
arm64: hugetlb: fix set_huge_pte_at() to work with all swap entries
mm: hugetlb: add huge page size param to set_huge_pte_at()
maple_tree: add MAS_UNDERFLOW and MAS_OVERFLOW states
maple_tree: add mas_is_active() to detect in-tree walks
nilfs2: fix potential use after free in nilfs_gccache_submit_read_data()
mm: abstract moving to the next PFN
mm: report success more often from filemap_map_folio_range()
fs: binfmt_elf_efpic: fix personality for ELF-FDPIC
Pull misc driver fix from Greg KH:
"Here is a single, much requested, fix for a set of misc drivers to
resolve a much reported regression in the -rc series that has also
propagated back to the stable releases. Sorry for the delay, lots of
conference travel for a few weeks put me very far behind in patch
wrangling.
It has been reported by many to resolve the reported problem, and has
been in linux-next with no reported issues"
* tag 'char-misc-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
misc: rtsx: Fix some platforms can not boot and move the l1ss judgment to probe
Pull tty / serial driver fixes from Greg KH:
"Here are two tty/serial driver fixes for 6.6-rc4 that resolve some
reported regressions:
- revert a n_gsm change that ended up causing problems
- 8250_port fix for irq data
both have been in linux-next for over a week with no reported
problems"
* tag 'tty-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux"
serial: 8250_port: Check IRQ data before use
Pull x86 fixes from Ingo Molnar:
"Misc fixes: a kerneldoc build warning fix, add SRSO mitigation for
AMD-derived Hygon processors, and fix a SGX kernel crash in the page
fault handler that can trigger when ksgxd races to reclaim the SECS
special page, by making the SECS page unswappable"
* tag 'x86-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Resolves SECS reclaim vs. page fault for EAUG race
x86/srso: Add SRSO mitigation for Hygon processors
x86/kgdb: Fix a kerneldoc warning when build with W=1
Pull timer fix from Ingo Molnar:
"Fix a spurious kernel warning during CPU hotplug events that may
trigger when timer/hrtimer softirqs are pending, which are otherwise
hotplug-safe and don't merit a warning"
* tag 'timers-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers: Tag (hr)timer softirq as hotplug safe
Pull scheduler fix from Ingo Molnar:
"Fix a RT tasks related lockup/live-lock during CPU offlining"
* tag 'sched-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/rt: Fix live lock between select_fallback_rq() and RT push
Pull perf event fixes from Ingo Molnar:
"Misc fixes: work around an AMD microcode bug on certain models, and
fix kexec kernel PMI handlers on AMD systems that get loaded on older
kernels that have an unexpected register state"
* tag 'perf-urgent-2023-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/amd: Do not WARN() on every IRQ
perf/x86/amd/core: Fix overflow reset on hotplug
Since commit d8131c2965 ("kbuild: remove $(MODLIB)/source symlink"),
modules_install does not create the 'source' symlink.
Remove the stale code from builddeb and kernel.spec.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Drivers must not reference functions marked with __exit as these likely
are not available when the code is built-in.
There are few creative offenders uncovered for example in ARCH=amd64
allmodconfig builds. So only trigger the section mismatch warning for
W=1 builds.
The dual rule that drivers must not reference .init.* is implemented
since commit 0db2524523 ("modpost: don't allow *driver to reference
.init.*") which however missed that .exit.* should be handled in the
same way.
Thanks to Masahiro Yamada and Arnd Bergmann who gave valuable hints to
find this improvement.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Without this 'else' statement, an "usb" name goes into two handlers:
the first/previous 'if' statement _AND_ the for-loop over 'devtable',
but the latter is useless as it has no 'usb' device_id entry anyway.
Tested with allmodconfig before/after patch; no changes to *.mod.c:
git checkout v6.6-rc3
make -j$(nproc) allmodconfig
make -j$(nproc) olddefconfig
make -j$(nproc)
find . -name '*.mod.c' | cpio -pd /tmp/before
# apply patch
make -j$(nproc)
find . -name '*.mod.c' | cpio -pd /tmp/after
diff -r /tmp/before/ /tmp/after/
# no difference
Fixes: acbef7b766 ("modpost: fix module autoloading for OF devices with generic compatible property")
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull ARM SoC fixes from Arnd Bergmann:
"These are the latest bug fixes that have come up in the soc tree. Most
of these are fairly minor. Most notably, the majority of changes this
time are not for dts files as usual.
- Updates to the addresses of the broadcom and aspeed entries in the
MAINTAINERS file.
- Defconfig updates to address a regression on samsung and a build
warning from an unknown Kconfig symbol
- Build fixes for the StrongARM and Uniphier platforms
- Code fixes for SCMI and FF-A firmware drivers, both of which had a
simple bug that resulted in invalid data, and a lesser fix for the
optee firmware driver
- Multiple fixes for the recently added loongson/loongarch "guts" soc
driver
- Devicetree fixes for RISC-V on the startfive platform, addressing
issues with NOR flash, usb and uart.
- Multiple fixes for NXP i.MX8/i.MX9 dts files, fixing problems with
clock, gpio, hdmi settings and the Makefile
- Bug fixes for i.MX firmware code and the OCOTP soc driver
- Multiple fixes for the TI sysc bus driver
- Minor dts updates for TI omap dts files, to address boot time
warnings and errors"
* tag 'soc-fixes-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (35 commits)
MAINTAINERS: Fix Florian Fainelli's email address
arm64: defconfig: enable syscon-poweroff driver
ARM: locomo: fix locomolcd_power declaration
soc: loongson: loongson2_guts: Remove unneeded semicolon
soc: loongson: loongson2_guts: Convert to devm_platform_ioremap_resource()
soc: loongson: loongson_pm2: Populate children syscon nodes
dt-bindings: soc: loongson,ls2k-pmc: Allow syscon-reboot/syscon-poweroff as child
soc: loongson: loongson_pm2: Drop useless of_device_id compatible
dt-bindings: soc: loongson,ls2k-pmc: Use fallbacks for ls2k-pmc compatible
soc: loongson: loongson_pm2: Add dependency for INPUT
arm64: defconfig: remove CONFIG_COMMON_CLK_NPCM8XX=y
ARM: uniphier: fix cache kernel-doc warnings
MAINTAINERS: aspeed: Update Andrew's email address
MAINTAINERS: aspeed: Update git tree URL
firmware: arm_ffa: Don't set the memory region attributes for MEM_LEND
arm64: dts: imx: Add imx8mm-prt8mm.dtb to build
arm64: dts: imx8mm-evk: Fix hdmi@3d node
soc: imx8m: Enable OCOTP clock for imx8mm before reading registers
arm64: dts: imx8mp-beacon-kit: Fix audio_pll2 clock
arm64: dts: imx8mp: Fix SDMA2/3 clocks
...
Pull tracing fixes from Steven Rostedt:
- Make sure 32-bit applications using user events have aligned access
when running on a 64-bit kernel.
- Add cond_resched in the loop that handles converting enums in
print_fmt string is trace events.
- Fix premature wake ups of polling processes in the tracing ring
buffer. When a task polls waiting for a percentage of the ring buffer
to be filled, the writer still will wake it up at every event. Add
the polling's percentage to the "shortest_full" list to tell the
writer when to wake it up.
- For eventfs dir lookups on dynamic events, an event system's only
event could be removed, leaving its dentry with no children. This is
totally legitimate. But in eventfs_release() it must not access the
children array, as it is only allocated when the dentry has children.
* tag 'trace-v6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
eventfs: Test for dentries array allocated in eventfs_release()
tracing/user_events: Align set_bit() address for all archs
tracing: relax trace_event_eval_update() execution with cond_resched()
ring-buffer: Update "shortest_full" in polling
All architectures should use a long aligned address passed to set_bit().
User processes can pass either a 32-bit or 64-bit sized value to be
updated when tracing is enabled when on a 64-bit kernel. Both cases are
ensured to be naturally aligned, however, that is not enough. The
address must be long aligned without affecting checks on the value
within the user process which require different adjustments for the bit
for little and big endian CPUs.
Add a compat flag to user_event_enabler that indicates when a 32-bit
value is being used on a 64-bit kernel. Long align addresses and correct
the bit to be used by set_bit() to account for this alignment. Ensure
compat flags are copied during forks and used during deletion clears.
Link: https://lore.kernel.org/linux-trace-kernel/20230925230829.341-2-beaub@linux.microsoft.com
Link: https://lore.kernel.org/linux-trace-kernel/20230914131102.179100-1-cleger@rivosinc.com/
Cc: stable@vger.kernel.org
Fixes: 7235759084 ("tracing/user_events: Use remote writes for event enablement")
Reported-by: Clément Léger <cleger@rivosinc.com>
Suggested-by: Clément Léger <cleger@rivosinc.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When kernel is compiled without preemption, the eval_map_work_func()
(which calls trace_event_eval_update()) will not be preempted up to its
complete execution. This can actually cause a problem since if another
CPU call stop_machine(), the call will have to wait for the
eval_map_work_func() function to finish executing in the workqueue
before being able to be scheduled. This problem was observe on a SMP
system at boot time, when the CPU calling the initcalls executed
clocksource_done_booting() which in the end calls stop_machine(). We
observed a 1 second delay because one CPU was executing
eval_map_work_func() and was not preempted by the stop_machine() task.
Adding a call to cond_resched() in trace_event_eval_update() allows
other tasks to be executed and thus continue working asynchronously
like before without blocking any pending task at boot time.
Link: https://lore.kernel.org/linux-trace-kernel/20230929191637.416931-1-cleger@rivosinc.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
It was discovered that the ring buffer polling was incorrectly stating
that read would not block, but that's because polling did not take into
account that reads will block if the "buffer-percent" was set. Instead,
the ring buffer polling would say reads would not block if there was any
data in the ring buffer. This was incorrect behavior from a user space
point of view. This was fixed by commit 42fb0a1e84 by having the polling
code check if the ring buffer had more data than what the user specified
"buffer percent" had.
The problem now is that the polling code did not register itself to the
writer that it wanted to wait for a specific "full" value of the ring
buffer. The result was that the writer would wake the polling waiter
whenever there was a new event. The polling waiter would then wake up, see
that there's not enough data in the ring buffer to notify user space and
then go back to sleep. The next event would wake it up again.
Before the polling fix was added, the code would wake up around 100 times
for a hackbench 30 benchmark. After the "fix", due to the constant waking
of the writer, it would wake up over 11,0000 times! It would never leave
the kernel, so the user space behavior was still "correct", but this
definitely is not the desired effect.
To fix this, have the polling code add what it's waiting for to the
"shortest_full" variable, to tell the writer not to wake it up if the
buffer is not as full as it expects to be.
Note, after this fix, it appears that the waiter is now woken up around 2x
the times it was before (~200). This is a tremendous improvement from the
11,000 times, but I will need to spend some time to see why polling is
more aggressive in its wakeups than the read blocking code.
Link: https://lore.kernel.org/linux-trace-kernel/20230929180113.01c2cae3@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Tested-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull dma-mapping fixes from Christoph Hellwig:
- fix the narea calculation in swiotlb initialization (Ross Lagerwall)
- fix the check whether a device has used swiotlb (Petr Tesarik)
* tag 'dma-mapping-6.6-2023-09-30' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: fix the check whether a device has used software IO TLB
swiotlb: use the calculated number of areas
Pull iomap fixes from Darrick Wong:
- Handle a race between writing and shrinking block devices by
returning EIO
- Fix a typo in a comment
* tag 'iomap-6.6-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
iomap: Spelling s/preceeding/preceding/g
iomap: add a workaround for racy i_size updates on block devices
Pull ACPI fix from Rafael Wysocki:
"Fix a possible NULL pointer dereference in the error path of
acpi_video_bus_add() resulting from recent changes (Dinghao Liu)"
* tag 'acpi-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: video: Fix NULL pointer dereference in acpi_video_bus_add()
Pull powerpc fixes from Michael Ellerman:
- Fix arch_stack_walk_reliable(), used by live patching
- Fix powerpc selftests to work with run_kselftest.sh
Thanks to Joe Lawrence and Petr Mladek.
* tag 'powerpc-6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
selftests/powerpc: Fix emit_tests to work with run_kselftest.sh
powerpc/stacktrace: Fix arch_stack_walk_reliable()
Pull nfsd fix from Chuck Lever:
- Fix NFSv4 READ corner case
* tag 'nfsd-6.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
NFSD: Fix zero NFSv4 READ results when RQ_SPLICE_OK is not set
Pull smb client fix from Steve French:
"Fix for password freeing potential oops (also for stable)"
* tag '6.6-rc3-smb3-client-fix' of git://git.samba.org/sfrench/cifs-2.6:
fs/smb/client: Reset password pointer to NULL
Eric reported that handling corresponding crash hotplug event can be
failed easily when many memory hotplug event are notified in a short
period. They failed because failing to take __kexec_lock.
=======
[ 78.714569] Fallback order for Node 0: 0
[ 78.714575] Built 1 zonelists, mobility grouping on. Total pages: 1817886
[ 78.717133] Policy zone: Normal
[ 78.724423] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[ 78.727207] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[ 80.056643] PEFILE: Unsigned PE binary
=======
The memory hotplug events are notified very quickly and very many, while
the handling of crash hotplug is much slower relatively. So the atomic
variable __kexec_lock and kexec_trylock() can't guarantee the
serialization of crash hotplug handling.
Here, add a new mutex lock __crash_hotplug_lock to serialize crash hotplug
handling specifically. This doesn't impact the usage of __kexec_lock.
Link: https://lkml.kernel.org/r/20230926120905.392903-1-bhe@redhat.com
Fixes: 2472627561 ("crash: add generic infrastructure for crash hotplug support")
Signed-off-by: Baoquan He <bhe@redhat.com>
Tested-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
