Pull asm-generic cleanup from Arnd Bergmann: "This is a single cleanup from Peter Collingbourne, removing some dead code" * tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: arch: remove unused function syscall_set_arguments()
Having a stable wchan means the process must be blocked and for it to stay that way while performing stack unwinding. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm] Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64] Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org
This function appears to have been unused since it was first introduced in
commit 828c365cc8b8 ("tracehook: asm/syscall.h").
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I8ce04f002903a37c0b6c1d16e9b2a3afa716c097
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull Kbuild updates from Masahiro Yamada: - Add -s option (strict mode) to merge_config.sh to make it fail when any symbol is redefined. - Show a warning if a different compiler is used for building external modules. - Infer --target from ARCH for CC=clang to let you cross-compile the kernel without CROSS_COMPILE. - Make the integrated assembler default (LLVM_IAS=1) for CC=clang. - Add <linux/stdarg.h> to the kernel source instead of borrowing <stdarg.h> from the compiler. - Add Nick Desaulniers as a Kbuild reviewer. - Drop stale cc-option tests. - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG to handle symbols in inline assembly. - Show a warning if 'FORCE' is missing for if_changed rules. - Various cleanups * tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits) kbuild: redo fake deps at include/ksym/*.h kbuild: clean up objtool_args slightly modpost: get the *.mod file path more simply checkkconfigsymbols.py: Fix the '--ignore' option kbuild: merge vmlinux_link() between ARCH=um and other architectures kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh kbuild: merge vmlinux_link() between the ordinary link and Clang LTO kbuild: remove stale *.symversions kbuild: remove unused quiet_cmd_update_lto_symversions gen_compile_commands: extract compiler command from a series of commands x86: remove cc-option-yn test for -mtune= arc: replace cc-option-yn uses with cc-option s390: replace cc-option-yn uses with cc-option ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild sparc: move the install rule to arch/sparc/Makefile security: remove unneeded subdir-$(CONFIG_...) kbuild: sh: remove unused install script kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y kbuild: Switch to 'f' variants of integrated assembler flag kbuild: Shuffle blank line to improve comment meaning ...
Pull printk updates from Petr Mladek: - Optionally, provide an index of possible printk messages via <debugfs>/printk/index/. It can be used when monitoring important kernel messages on a farm of various hosts. The monitor has to be updated when some messages has changed or are not longer available by a newly deployed kernel. - Add printk.console_no_auto_verbose boot parameter. It allows to generate crash dump even with slow consoles in a reasonable time frame. - Remove printk_safe buffers. The messages are always stored directly to the main logbuffer, even in NMI or recursive context. Also it allows to serialize syslog operations by a mutex instead of a spin lock. - Misc clean up and build fixes. * tag 'printk-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk/index: Fix -Wunused-function warning lib/nmi_backtrace: Serialize even messages about idle CPUs printk: Add printk.console_no_auto_verbose boot parameter printk: Remove console_silent() lib/test_scanf: Handle n_bits == 0 in random tests printk: syslog: close window between wait and read printk: convert @syslog_lock to mutex printk: remove NMI tracking printk: remove safe buffers printk: track/limit recursion lib/nmi_backtrace: explicitly serialize banner and regs printk: Move the printk() kerneldoc comment to its new home printk/index: Fix warning about missing prototypes MIPS/asm/printk: Fix build failure caused by printk printk: index: Add indexing support to dev_printk printk: Userspace format indexing support printk: Rework parse_prefix into printk_parse_prefix printk: Straighten out log_flags into printk_info_flags string_helpers: Escape double quotes in escape_special printk/console: Check consistent sequence number when handling race in console_unlock()
Delete/fixup few includes in anticipation of global -isystem compile option removal. Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition of uintptr_t error (one definition comes from <stddef.h>, another from <linux/types.h>). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
As these are now in asm-generic, it's no longer necessary to declare them in the architecture. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This is a preparation for changing over architectures to the generic implementation one at a time. As there are no callers of either __strncpy_from_user() or __strnlen_user(), fold these into the strncpy_from_user() and strnlen_user() functions to make each implementation independent of the others. Many of these implementations have known bugs, but the intention here is to not change behavior at all and stay compatible with those bugs for the moment. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
We have a number of systems industry-wide that have a subset of their
functionality that works as follows:
1. Receive a message from local kmsg, serial console, or netconsole;
2. Apply a set of rules to classify the message;
3. Do something based on this classification (like scheduling a
remediation for the machine), rinse, and repeat.
As a couple of examples of places we have this implemented just inside
Facebook, although this isn't a Facebook-specific problem, we have this
inside our netconsole processing (for alarm classification), and as part
of our machine health checking. We use these messages to determine
fairly important metrics around production health, and it's important
that we get them right.
While for some kinds of issues we have counters, tracepoints, or metrics
with a stable interface which can reliably indicate the issue, in order
to react to production issues quickly we need to work with the interface
which most kernel developers naturally use when developing: printk.
Most production issues come from unexpected phenomena, and as such
usually the code in question doesn't have easily usable tracepoints or
other counters available for the specific problem being mitigated. We
have a number of lines of monitoring defence against problems in
production (host metrics, process metrics, service metrics, etc), and
where it's not feasible to reliably monitor at another level, this kind
of pragmatic netconsole monitoring is essential.
As one would expect, monitoring using printk is rather brittle for a
number of reasons -- most notably that the message might disappear
entirely in a new version of the kernel, or that the message may change
in some way that the regex or other classification methods start to
silently fail.
One factor that makes this even harder is that, under normal operation,
many of these messages are never expected to be hit. For example, there
may be a rare hardware bug which one wants to detect if it was to ever
happen again, but its recurrence is not likely or anticipated. This
precludes using something like checking whether the printk in question
was printed somewhere fleetwide recently to determine whether the
message in question is still present or not, since we don't anticipate
that it should be printed anywhere, but still need to monitor for its
future presence in the long-term.
This class of issue has happened on a number of occasions, causing
unhealthy machines with hardware issues to remain in production for
longer than ideal. As a recent example, some monitoring around
blk_update_request fell out of date and caused semi-broken machines to
remain in production for longer than would be desirable.
Searching through the codebase to find the message is also extremely
fragile, because many of the messages are further constructed beyond
their callsite (eg. btrfs_printk and other module-specific wrappers,
each with their own functionality). Even if they aren't, guessing the
format and formulation of the underlying message based on the aesthetics
of the message emitted is not a recipe for success at scale, and our
previous issues with fleetwide machine health checking demonstrate as
much.
This provides a solution to the issue of silently changed or deleted
printks: we record pointers to all printk format strings known at
compile time into a new .printk_index section, both in vmlinux and
modules. At runtime, this can then be iterated by looking at
<debugfs>/printk/index/<module>, which emits the following format, both
readable by humans and able to be parsed by machines:
$ head -1 vmlinux; shuf -n 5 vmlinux
# <level[,flags]> filename:line function "format"
<5> block/blk-settings.c:661 disk_stack_limits "%s: Warning: Device %s is misaligned\n"
<4> kernel/trace/trace.c:8296 trace_create_file "Could not create tracefs '%s' entry\n"
<6> arch/x86/kernel/hpet.c:144 _hpet_print_config "hpet: %s(%d):\n"
<6> init/do_mounts.c:605 prepare_namespace "Waiting for root device %s...\n"
<6> drivers/acpi/osl.c:1410 acpi_no_auto_serialize_setup "ACPI: auto-serialization disabled\n"
This mitigates the majority of cases where we have a highly-specific
printk which we want to match on, as we can now enumerate and check
whether the format changed or the printk callsite disappeared entirely
in userspace. This allows us to catch changes to printks we monitor
earlier and decide what to do about it before it becomes problematic.
There is no additional runtime cost for printk callers or printk itself,
and the assembly generated is exactly the same.
Signed-off-by: Chris Down <chris@chrisdown.name>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Jessica Yu <jeyu@kernel.org> # for module.{c,h}
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/e42070983637ac5e384f17fbdbe86d19c7b212a5.1623775748.git.chris@chrisdown.name
Pull UML updates from Richard Weinberger: - Support for optimized routines based on the host CPU - Support for PCI via virtio - Various fixes * tag 'for-linus-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: remove unneeded semicolon in um_arch.c um: Remove the repeated declaration um: fix error return code in winch_tramp() um: fix error return code in slip_open() um: Fix stack pointer alignment um: implement flush_cache_vmap/flush_cache_vunmap um: add a UML specific futex implementation um: enable the use of optimized xor routines in UML um: Add support for host CPU flags and alignment um: allow not setting extra rpaths in the linux binary um: virtio/pci: enable suspend/resume um: add PCI over virtio emulation driver um: irqs: allow invoking time-travel handler multiple times um: time-travel/signals: fix ndelay() in interrupt um: expose time-travel mode to userspace side um: export signals_enabled directly um: remove unused smp_sigio_handler() declaration lib: add iomem emulation (logic_iomem) um: allow disabling NO_IOMEM