Since commit 533059281e ("tracing: probeevent: Introduce new
argument fetching code") dropped the $comm support from uprobe
events, this re-enables it.
For $comm support, uses strlcpy() instead of strncpy_from_user()
to copy current task's comm. Because it is in the kernel space,
strncpy_from_user() always fails to copy the comm.
This also uses strlen() instead of strnlen_user() to measure the
length of the comm.
Note that this uses -ECOMM as a token value to fetch the comm
string. If the user-space pointer points -ECOMM, it will be
translated to task->comm.
Link: http://lkml.kernel.org/r/155723734162.9149.4042756162201097965.stgit@devnote2
Fixes: 533059281e ("tracing: probeevent: Introduce new argument fetching code")
Reported-by: Andreas Ziegler <andreas.ziegler@fau.de>
Acked-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The 'ftdump' command in kdb is currently a bit of a last resort, at
least if you have lots of traces turned on. It's going to print a
whole boatload of data out your serial port which is probably running
at 115200. This could easily take many, many minutes.
Usually you're most interested in what's at the _end_ of the ftrace
buffer, AKA what happened most recently. That means you've got to
wait the full time for the dump. The 'ftdump' command does attempt to
help you a little bit by allowing you to skip a fixed number of
entries. Unfortunately it provides no way for you to know how many
entries you should skip.
Let's do similar to python and allow you to use a negative number to
indicate that you want to skip all entries except the last few. This
allows you to quickly see what you want.
Note that we also change the printout in ftdump to print the
(positive) number of entries actually skipped since that could be
helpful to know when you've specified a negative skip count.
Link: http://lkml.kernel.org/r/20190319171206.97107-3-dianders@chromium.org
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
These two new exported functions will be used in a future patch by
kdb_ftdump() to quickly skip all but the last few trace entries.
Link: http://lkml.kernel.org/r/20190319171206.97107-2-dianders@chromium.org
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The things skipped by kdb's "ftdump" command when you pass it a
parameter has always been entries, not lines. The difference usually
doesn't matter but when the trace buffer has multi-line entries (like
a stack dump) it can matter.
Let's fix this both in the help text for ftdump and also in the local
variable names.
Link: http://lkml.kernel.org/r/20190319171206.97107-1-dianders@chromium.org
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The function_graph boot up self test emulates the tr->init() function in
order to add a wrapper around the function graph tracer entry code to test
for lock ups and such. But it does not emulate the tr->reset(), and just
calls the function_graph tracer tr->reset() function which will use its own
fgraph_ops to unregister function tracing with. As the fgraph_ops is
becoming more meaningful with the register_ftrace_graph() and
unregister_ftrace_graph() functions, the two need to be the same. The
emulated tr->init() uses its own fgraph_ops descriptor, which means the
unregister_ftrace_graph() must use the same ftrace_ops, which the selftest
currently does not do. By emulating the tr->reset() as the selftest does
with the tr->init() it will be able to pass the same fgraph_ops descriptor
to the unregister_ftrace_graph() as it did with the register_ftrace_graph().
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The function_graph tracer has a stub function and its ops flag has the
FTRACE_OPS_FL_STUB set. As the function graph does not use the
ftrace_ops->func pointer but instead is called by a separate part of the
ftrace trampoline. The function_graph tracer still requires to pass in a
ftrace_ops that may also hold the hash of the functions to call. But there's
no reason to test that hash in the function tracing portion. Instead of
testing to see if we should call the stub function, just test if the ops has
FTRACE_OPS_FL_STUB set, and just skip it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The ASSIGN_OPS_HASH() macro was moved to fgraph.c where it was used, but for
some reason it wasn't removed from ftrace.c, as it is no longer referenced
there.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When CONFIG_RCU_TRACE is not set, all these tracepoints are defined as
do-nothing macro.
We'd better make those inline functions that take proper arguments.
As RCU_TRACE() is defined as do-nothing marco as well when
CONFIG_RCU_TRACE is not set, so we can clean it up.
Link: http://lkml.kernel.org/r/1553602391-11926-4-git-send-email-laoar.shao@gmail.com
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As each instance has their own error_log file, it makes more sense that the
instances show the errors of their own instead of all error_logs having the
same data. Make it that the errors show up in the instance error_log file
that the error happens in. If no instance trace_array is available, then
NULL can be passed in which will create the error in the top level instance
(the one at the top of the tracefs directory).
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Have the trace_array that associates the trace instance of the histogram
passed around to functions so that error handling can display the error
message in the proper instance.
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pass in the trace_array that represents the instance the filter being
changed is in to create_event_filter(). This will allow for error messages
that happen when writing to the filter can be displayed in the proper
instance "error_log" file.
Note, for calls to create_filter() (that was also modified to support
create_event_filter()), that changes filters that do not exist in a instance
(for perf for example), NULL may be passed in, which means that there will
not be any message to log for that filter.
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Use tracing error_log with probe events for logging error more
precisely. This also makes all parse error returns -EINVAL
(except for -ENOMEM), because user can see better error message
in error_log file now.
Link: http://lkml.kernel.org/r/6a4d90e141d138040ea61f4776b991597077451e.1554072478.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Use tracing_log_err() from the new tracing error_log mechanism to send
filter parse errors to tracing/error_log.
With this change, users will be able to see filter errors by looking
at tracing/error_log.
The same errors will also be available in the filter file, as
expected.
Link: http://lkml.kernel.org/r/1d942c419941539a11d78a6810fc5740a99b2974.1554072478.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Replace hist_err() and hist_err_event() with tracing_log_err() from
the new tracing error_log mechanism.
Also add a couple related helper functions and remove most of the old
hist_err()-related code.
With this change, users no longer read the hist files for hist trigger
error information, but instead look at tracing/error_log for the same
information.
Link: http://lkml.kernel.org/r/c98f77a97c9715d18b623eeb5741057b330d5ac0.1554072478.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In preparation for making use of the new trace error log, save the
subsystem and event name associated with the last hist command - it
will be passed as the location param in the event_log_err() calls.
Link: http://lkml.kernel.org/r/eb0fd1362be8f39facb86c83eecf441b7a5876f8.1554072478.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Introduce a new ftrace file, tracing/error_log, for ftrace commands to
log errors. This is useful for allowing more complex commands such as
hist trigger and kprobe_event commands to point out specifically where
something may have gone wrong without forcing them to resort to more
ad hoc methods such as tacking error messages onto existing output
files.
To log a tracing error, call the event_log_err() function, passing it
a location string describing where it came from e.g. kprobe_events or
system:event, the command that caused the error, an array of static
error strings describing errors and an index within that array which
describes the specific error, along with the position to place the
error caret.
Reading the log displays the last (currently) 8 errors logged in the
following format:
[timestamp] <loc>: error: <static error text>
Command: <command that caused the error>
^
Memory for the error log isn't allocated unless there has been a trace
event error, and the error log can be cleared and have its memory
freed by writing the empty string in truncation mode to it:
# echo > tracing/error_log.
Link: http://lkml.kernel.org/r/0c2c82571fd38c5f3a88ca823627edff250e9416.1554072478.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Improvements-suggested-by: Steve Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Ftrace provides the feature “instances” that provides the capability to
create multiple Ftrace ring buffers. However, currently these buffers
are created/accessed via userspace only. The kernel APIs providing these
features are not exported, hence cannot be used by other kernel
components.
This patch aims to extend this infrastructure to provide the
flexibility to create/log/remove/ enable-disable existing trace events
to these buffers from within the kernel.
Link: http://lkml.kernel.org/r/1553106531-3281-2-git-send-email-divya.indi@oracle.com
Signed-off-by: Divya Indi <divya.indi@oracle.com>
Reviewed-by: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull CPU hotplug fixes from Thomas Gleixner:
"Two SMT/hotplug related fixes:
- Prevent crash when HOTPLUG_CPU is disabled and the CPU bringup
aborts. This is triggered with the 'nosmt' command line option, but
can happen by any abort condition. As the real unplug code is not
compiled in, prevent the fail by keeping the CPU in zombie state.
- Enforce HOTPLUG_CPU for SMP on x86 to avoid the above situation
completely. With 'nosmt' being a popular option it's required to
unplug the half brought up sibling CPUs (due to the MCE wreckage)
completely"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y
cpu/hotplug: Prevent crash when CPU bringup fails on CONFIG_HOTPLUG_CPU=n
Pull core fixes from Thomas Gleixner:
"A small set of core updates:
- Make the watchdog respect the selected CPU mask again. That was
broken by the rework of the watchdog thread management and caused
inconsistent state and NMI watchdog being unstoppable.
- Ensure that the objtool build can find the libelf location.
- Remove dead kcore stub code"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
watchdog: Respect watchdog cpumask on CPU hotplug
objtool: Query pkg-config for libelf location
proc/kcore: Remove unused kclist_add_remap()
There are a few system calls (pselect, ppoll, etc) which replace a task
sigmask while they are running in a kernel-space
When a task calls one of these syscalls, the kernel saves a current
sigmask in task->saved_sigmask and sets a syscall sigmask.
On syscall-exit-stop, ptrace traps a task before restoring the
saved_sigmask, so PTRACE_GETSIGMASK returns the syscall sigmask and
PTRACE_SETSIGMASK does nothing, because its sigmask is replaced by
saved_sigmask, when the task returns to user-space.
This patch fixes this problem. PTRACE_GETSIGMASK returns saved_sigmask
if it's set. PTRACE_SETSIGMASK drops the TIF_RESTORE_SIGMASK flag.
Link: http://lkml.kernel.org/r/20181120060616.6043-1-avagin@gmail.com
Fixes: 29000caecb ("ptrace: add ability to get/set signal-blocked mask")
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tianyu reported a crash in a CPU hotplug teardown callback when booting a
kernel which has CONFIG_HOTPLUG_CPU disabled with the 'nosmt' boot
parameter.
It turns out that the SMP=y CONFIG_HOTPLUG_CPU=n case has been broken
forever in case that a bringup callback fails. Unfortunately this issue was
not recognized when the CPU hotplug code was reworked, so the shortcoming
just stayed in place.
When a bringup callback fails, the CPU hotplug code rolls back the
operation and takes the CPU offline.
The 'nosmt' command line argument uses a bringup failure to abort the
bringup of SMT sibling CPUs. This partial bringup is required due to the
MCE misdesign on Intel CPUs.
With CONFIG_HOTPLUG_CPU=y the rollback works perfectly fine, but
CONFIG_HOTPLUG_CPU=n lacks essential mechanisms to exercise the low level
teardown of a CPU including the synchronizations in various facilities like
RCU, NOHZ and others.
As a consequence the teardown callbacks which must be executed on the
outgoing CPU within stop machine with interrupts disabled are executed on
the control CPU in interrupt enabled and preemptible context causing the
kernel to crash and burn. The pre state machine code has a different
failure mode which is more subtle and resulting in a less obvious use after
free crash because the control side frees resources which are still in use
by the undead CPU.
But this is not a x86 only problem. Any architecture which supports the
SMP=y HOTPLUG_CPU=n combination suffers from the same issue. It's just less
likely to be triggered because in 99.99999% of the cases all bringup
callbacks succeed.
The easy solution of making HOTPLUG_CPU mandatory for SMP is not working on
all architectures as the following architectures have either no hotplug
support at all or not all subarchitectures support it:
alpha, arc, hexagon, openrisc, riscv, sparc (32bit), mips (partial).
Crashing the kernel in such a situation is not an acceptable state
either.
Implement a minimal rollback variant by limiting the teardown to the point
where all regular teardown callbacks have been invoked and leave the CPU in
the 'dead' idle state. This has the following consequences:
- the CPU is brought down to the point where the stop_machine takedown
would happen.
- the CPU stays there forever and is idle
- The CPU is cleared in the CPU active mask, but not in the CPU online
mask which is a legit state.
- Interrupts are not forced away from the CPU
- All facilities which only look at online mask would still see it, but
that is the case during normal hotplug/unplug operations as well. It's
just a (way) longer time frame.
This will expose issues, which haven't been exposed before or only seldom,
because now the normally transient state of being non active but online is
a permanent state. In testing this exposed already an issue vs. work queues
where the vmstat code schedules work on the almost dead CPU which ends up
in an unbound workqueue and triggers 'preemtible context' warnings. This is
not a problem of this change, it merily exposes an already existing issue.
Still this is better than crashing fully without a chance to debug it.
This is mainly thought as workaround for those architectures which do not
support HOTPLUG_CPU. All others should enforce HOTPLUG_CPU for SMP.
Fixes: 2e1a3483ce ("cpu/hotplug: Split out the state walk into functions")
Reported-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Mukesh Ojha <mojha@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@surriel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Micheal Kelley <michael.h.kelley@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190326163811.503390616@linutronix.de
The rework of the watchdog core to use cpu_stop_work broke the watchdog
cpumask on CPU hotplug.
The watchdog_enable/disable() functions are now called unconditionally from
the hotplug callback, i.e. even on CPUs which are not in the watchdog
cpumask. As a consequence the watchdog can become unstoppable.
Only invoke them when the plugged CPU is in the watchdog cpumask.
Fixes: 9cf57731b6 ("watchdog/softlockup: Replace "watchdog/%u" threads with cpu_stop_work")
Reported-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1903262245490.1789@nanos.tec.linutronix.de
Pull networking fixes from David Miller:
"Fixes here and there, a couple new device IDs, as usual:
1) Fix BQL race in dpaa2-eth driver, from Ioana Ciornei.
2) Fix 64-bit division in iwlwifi, from Arnd Bergmann.
3) Fix documentation for some eBPF helpers, from Quentin Monnet.
4) Some UAPI bpf header sync with tools, also from Quentin Monnet.
5) Set descriptor ownership bit at the right time for jumbo frames in
stmmac driver, from Aaro Koskinen.
6) Set IFF_UP properly in tun driver, from Eric Dumazet.
7) Fix load/store doubleword instruction generation in powerpc eBPF
JIT, from Naveen N. Rao.
8) nla_nest_start() return value checks all over, from Kangjie Lu.
9) Fix asoc_id handling in SCTP after the SCTP_*_ASSOC changes this
merge window. From Marcelo Ricardo Leitner and Xin Long.
10) Fix memory corruption with large MTUs in stmmac, from Aaro
Koskinen.
11) Do not use ipv4 header for ipv6 flows in TCP and DCCP, from Eric
Dumazet.
12) Fix topology subscription cancellation in tipc, from Erik Hugne.
13) Memory leak in genetlink error path, from Yue Haibing.
14) Valid control actions properly in packet scheduler, from Davide
Caratti.
15) Even if we get EEXIST, we still need to rehash if a shrink was
delayed. From Herbert Xu.
16) Fix interrupt mask handling in interrupt handler of r8169, from
Heiner Kallweit.
17) Fix leak in ehea driver, from Wen Yang"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (168 commits)
dpaa2-eth: fix race condition with bql frame accounting
chelsio: use BUG() instead of BUG_ON(1)
net: devlink: skip info_get op call if it is not defined in dumpit
net: phy: bcm54xx: Encode link speed and activity into LEDs
tipc: change to check tipc_own_id to return in tipc_net_stop
net: usb: aqc111: Extend HWID table by QNAP device
net: sched: Kconfig: update reference link for PIE
net: dsa: qca8k: extend slave-bus implementations
net: dsa: qca8k: remove leftover phy accessors
dt-bindings: net: dsa: qca8k: support internal mdio-bus
dt-bindings: net: dsa: qca8k: fix example
net: phy: don't clear BMCR in genphy_soft_reset
bpf, libbpf: clarify bump in libbpf version info
bpf, libbpf: fix version info and add it to shared object
rxrpc: avoid clang -Wuninitialized warning
tipc: tipc clang warning
net: sched: fix cleanup NULL pointer exception in act_mirr
r8169: fix cable re-plugging issue
net: ethernet: ti: fix possible object reference leak
net: ibm: fix possible object reference leak
...
Fix compile warning in create_dyn_event(): 'ret' may be used uninitialized
in this function [-Wuninitialized].
Link: http://lkml.kernel.org/r/1553237900-8555-1-git-send-email-frowand.list@gmail.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Fixes: 5448d44c38 ("tracing: Add unified dynamic event framework")
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull scheduler updates from Thomas Gleixner:
"Third more careful attempt for this set of fixes:
- Prevent a 32bit math overflow in the cpufreq code
- Fix a buffer overflow when scanning the cgroup2 cpu.max property
- A set of fixes for the NOHZ scheduler logic to prevent waking up
CPUs even if the capacity of the busy CPUs is sufficient along with
other tweaks optimizing the behaviour for asymmetric systems
(big/little)"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Skip LLC NOHZ logic for asymmetric systems
sched/fair: Tune down misfit NOHZ kicks
sched/fair: Comment some nohz_balancer_kick() kick conditions
sched/core: Fix buffer overflow in cgroup2 property cpu.max
sched/cpufreq: Fix 32-bit math overflow
Pull perf updates from Thomas Gleixner:
"A larger set of perf updates.
Not all of them are strictly fixes, but that's solely the tip
maintainers fault as they let the timely -rc1 pull request fall
through the cracks for various reasons including travel. So I'm
sending this nevertheless because rebasing and distangling fixes and
updates would be a mess and risky as well. As of tomorrow, a strict
fixes separation is happening again. Sorry for the slip-up.
Kernel:
- Handle RECORD_MMAP vs. RECORD_MMAP2 correctly so different
consumers of the mmap event get what they requested.
Tools:
- A larger set of updates to perf record/report/scripts vs. time
stamp handling
- More Python3 fixups
- A pile of memory leak plumbing
- perf BPF improvements and fixes
- Finalize the perf.data directory storage"
[ Note: the kernel part is strictly a fix, the updates are purely to
tooling - Linus ]
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
perf bpf: Show more BPF program info in print_bpf_prog_info()
perf bpf: Extract logic to create program names from perf_event__synthesize_one_bpf_prog()
perf tools: Save bpf_prog_info and BTF of new BPF programs
perf evlist: Introduce side band thread
perf annotate: Enable annotation of BPF programs
perf build: Check what binutils's 'disassembler()' signature to use
perf bpf: Process PERF_BPF_EVENT_PROG_LOAD for annotation
perf symbols: Introduce DSO_BINARY_TYPE__BPF_PROG_INFO
perf feature detection: Add -lopcodes to feature-libbfd
perf top: Add option --no-bpf-event
perf bpf: Save BTF information as headers to perf.data
perf bpf: Save BTF in a rbtree in perf_env
perf bpf: Save bpf_prog_info information as headers to perf.data
perf bpf: Save bpf_prog_info in a rbtree in perf_env
perf bpf: Make synthesize_bpf_events() receive perf_session pointer instead of perf_tool
perf bpf: Synthesize bpf events with bpf_program__get_prog_info_linear()
bpftool: use bpf_program__get_prog_info_linear() in prog.c:do_dump()
tools lib bpf: Introduce bpf_program__get_prog_info_linear()
perf record: Replace option --bpf-event with --no-bpf-event
perf tests: Fix a memory leak in test__perf_evsel__tp_sched_test()
...
Pull timer fixes from Thomas Gleixner:
"A set of small fixes plus the removal of stale board support code:
- Remove the board support code from the clpx711x clocksource driver.
This change had fallen through the cracks and I'm sending it now
rather than dealing with people who want to improve that stale code
for 3 month.
- Use the proper clocksource mask on RICSV
- Make local scope functions and variables static"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/clps711x: Remove board support
clocksource/drivers/riscv: Fix clocksource mask
clocksource/drivers/mips-gic-timer: Make gic_compare_irqaction static
clocksource/drivers/timer-ti-dm: Make omap_dm_timer_set_load_start() static
clocksource/drivers/tcb_clksrc: Make tc_clksrc_suspend/resume() static
clocksource/drivers/clps711x: Make clps711x_clksrc_init() static
time/jiffies: Make refined_jiffies static
Pull locking fixes from Thomas Gleixner:
"Two small fixes:
- Cure a recently introduces error path hickup which tries to
unregister a not registered lockdep key in te workqueue code
- Prevent unaligned cmpxchg() crashes in the robust list handling
code by sanity checking the user space supplied futex pointer"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Ensure that futex address is aligned in handle_futex_death()
workqueue: Only unregister a registered lockdep key
Pull irq fixes from Thomas Gleixner:
"A set of fixes for the interrupt subsystem:
- Remove secondary GIC support on systems w/o device-tree support
- A set of small fixlets in various irqchip drivers
- static and fall-through annotations
- Kernel doc and typo fixes"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Mark expected switch case fall-through
genirq/devres: Remove excess parameter from kernel doc
irqchip/irq-mvebu-sei: Make mvebu_sei_ap806_caps static
irqchip/mbigen: Don't clear eventid when freeing an MSI
irqchip/stm32: Don't set rising configuration registers at init
irqchip/stm32: Don't clear rising/falling config registers at init
dt-bindings: irqchip: renesas-irqc: Document r8a774c0 support
irqchip/mmp: Make mmp_irq_domain_ops static
irqchip/brcmstb-l2: Make two init functions static
genirq: Fix typo in comment of IRQD_MOVE_PCNTXT
irqchip/gic-v3-its: Fix comparison logic in lpi_range_cmp
irqchip/gic: Drop support for secondary GIC in non-DT systems
irqchip/imx-irqsteer: Fix of_property_read_u32() error handling
In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.
With -Wimplicit-fallthrough added to CFLAGS:
kernel/irq/manage.c: In function ‘irq_do_set_affinity’:
kernel/irq/manage.c:198:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
cpumask_copy(desc->irq_common_data.affinity, mask);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/irq/manage.c:199:2: note: here
case IRQ_SET_MASK_OK_NOCOPY:
^~~~
Annotate it.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20190228213714.GA9246@embeddedor
kernel:
Stephane Eranian :
- Restore mmap record type correctly when handling PERF_RECORD_MMAP2
events, as the same template is used for all the threads interested
in mmap events, some may want just PERF_RECORD_MMAP, while some
may want the extra info in MMAP2 records.
perf probe:
Adrian Hunter:
- Fix getting the kernel map, because since changes related to x86 PTI
entry trampolines handling, there are more than one kernel map.
perf script:
Andi Kleen:
- Support insn output for normal samples, i.e.:
perf script -F ip,sym,insn --xed
Will fetch the sample IP from the thread address space and feed it
to Intel's XED disassembler, producing lines such as:
ffffffffa4068804 native_write_msr wrmsr
ffffffffa415b95e __hrtimer_next_event_base movq 0x18(%rax), %rdx
That match 'perf annotate's output.
- Make the --cpu filter apply to PERF_RECORD_COMM/FORK/... events, in
addition to PERF_RECORD_SAMPLE.
perf report:
- Add a new --samples option to save a small random number of samples
per hist entry, using a reservoir technique to select a representative
number of samples.
Then allow browsing the samples using 'perf script' as part of the hist
entry context menu. This automatically adds the right filters, so only
the thread or CPU of the sample is displayed. Then we use less' search
functionality to directly jump to the time stamp of the selected sample.
It uses different menus for assembler and source display. Assembler
needs xed installed and source needs debuginfo.
- Fix the UI browser scripts pop up menu when there are many scripts
available.
perf report:
Andi Kleen:
- Add 'time' sort option. E.g.:
% perf report --sort time,overhead,symbol --time-quantum 1ms --stdio
...
0.67% 277061.87300 [.] _dl_start
0.50% 277061.87300 [.] f1
0.50% 277061.87300 [.] f2
0.33% 277061.87300 [.] main
0.29% 277061.87300 [.] _dl_lookup_symbol_x
0.29% 277061.87300 [.] dl_main
0.29% 277061.87300 [.] do_lookup_x
0.17% 277061.87300 [.] _dl_debug_initialize
0.17% 277061.87300 [.] _dl_init_paths
0.08% 277061.87300 [.] check_match
0.04% 277061.87300 [.] _dl_count_modids
1.33% 277061.87400 [.] f1
1.33% 277061.87400 [.] f2
1.33% 277061.87400 [.] main
1.17% 277061.87500 [.] main
1.08% 277061.87500 [.] f1
1.08% 277061.87500 [.] f2
1.00% 277061.87600 [.] main
0.83% 277061.87600 [.] f1
0.83% 277061.87600 [.] f2
1.00% 277061.87700 [.] main
tools headers:
Arnaldo Carvalho de Melo:
- Update x86's syscall_64.tbl, no change in tools/perf behaviour.
- Sync copies asm-generic/unistd.h and linux/in with the kernel sources.
perf data:
Jiri Olsa:
- Prep work to support having perf.data stored as a directory, with one
file per CPU, that ultimately will allow having one ring buffer reading
thread per CPU.
Vendor events:
Martin Liška:
- perf PMU events for AMD Family 17h.
perf script python:
Tony Jones:
- Add python3 support for the remaining Intel PT related scripts, with
these we should have a clean build of perf with python3 while still
supporting the build with python2.
libbpf:
Arnaldo Carvalho de Melo:
- Fix the build on uCLibc, adding the missing stdarg.h since we use
va_list in one typedef.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-core-for-mingo-5.1-20190311' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
Pull perf/core improvements and fixes from Arnaldo:
kernel:
Stephane Eranian :
- Restore mmap record type correctly when handling PERF_RECORD_MMAP2
events, as the same template is used for all the threads interested
in mmap events, some may want just PERF_RECORD_MMAP, while some
may want the extra info in MMAP2 records.
perf probe:
Adrian Hunter:
- Fix getting the kernel map, because since changes related to x86 PTI
entry trampolines handling, there are more than one kernel map.
perf script:
Andi Kleen:
- Support insn output for normal samples, i.e.:
perf script -F ip,sym,insn --xed
Will fetch the sample IP from the thread address space and feed it
to Intel's XED disassembler, producing lines such as:
ffffffffa4068804 native_write_msr wrmsr
ffffffffa415b95e __hrtimer_next_event_base movq 0x18(%rax), %rdx
That match 'perf annotate's output.
- Make the --cpu filter apply to PERF_RECORD_COMM/FORK/... events, in
addition to PERF_RECORD_SAMPLE.
perf report:
- Add a new --samples option to save a small random number of samples
per hist entry, using a reservoir technique to select a representative
number of samples.
Then allow browsing the samples using 'perf script' as part of the hist
entry context menu. This automatically adds the right filters, so only
the thread or CPU of the sample is displayed. Then we use less' search
functionality to directly jump to the time stamp of the selected sample.
It uses different menus for assembler and source display. Assembler
needs xed installed and source needs debuginfo.
- Fix the UI browser scripts pop up menu when there are many scripts
available.
perf report:
Andi Kleen:
- Add 'time' sort option. E.g.:
% perf report --sort time,overhead,symbol --time-quantum 1ms --stdio
...
0.67% 277061.87300 [.] _dl_start
0.50% 277061.87300 [.] f1
0.50% 277061.87300 [.] f2
0.33% 277061.87300 [.] main
0.29% 277061.87300 [.] _dl_lookup_symbol_x
0.29% 277061.87300 [.] dl_main
0.29% 277061.87300 [.] do_lookup_x
0.17% 277061.87300 [.] _dl_debug_initialize
0.17% 277061.87300 [.] _dl_init_paths
0.08% 277061.87300 [.] check_match
0.04% 277061.87300 [.] _dl_count_modids
1.33% 277061.87400 [.] f1
1.33% 277061.87400 [.] f2
1.33% 277061.87400 [.] main
1.17% 277061.87500 [.] main
1.08% 277061.87500 [.] f1
1.08% 277061.87500 [.] f2
1.00% 277061.87600 [.] main
0.83% 277061.87600 [.] f1
0.83% 277061.87600 [.] f2
1.00% 277061.87700 [.] main
tools headers:
Arnaldo Carvalho de Melo:
- Update x86's syscall_64.tbl, no change in tools/perf behaviour.
- Sync copies asm-generic/unistd.h and linux/in with the kernel sources.
perf data:
Jiri Olsa:
- Prep work to support having perf.data stored as a directory, with one
file per CPU, that ultimately will allow having one ring buffer reading
thread per CPU.
Vendor events:
Martin Liška:
- perf PMU events for AMD Family 17h.
perf script python:
Tony Jones:
- Add python3 support for the remaining Intel PT related scripts, with
these we should have a clean build of perf with python3 while still
supporting the build with python2.
libbpf:
Arnaldo Carvalho de Melo:
- Fix the build on uCLibc, adding the missing stdarg.h since we use
va_list in one typedef.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
sparse complains:
CHECK kernel/watchdog.c
kernel/watchdog.c:45:19: warning: symbol 'nmi_watchdog_available'
was not declared. Should it be static?
kernel/watchdog.c:47:16: warning: symbol 'watchdog_allowed_mask'
was not declared. Should it be static?
They're not referenced by name from anyplace else, make them static.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/7855.1552383228@turing-police
sparse complains:
CHECK kernel/time/jiffies.c
kernel/time/jiffies.c:92:20: warning: symbol 'refined_jiffies' was not
declared. Should it be static?
Its only used in file scope. Make it static.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/32342.1552379915@turing-police
Building with 'make W=1' complains:
CC kernel/irq/devres.o
kernel/irq/devres.c:104: warning: Excess function parameter 'thread_fn'
description in 'devm_request_any_context_irq'
Remove it.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/31207.1552378676@turing-police
The futex code requires that the user space addresses of futexes are 32bit
aligned. sys_futex() checks this in futex_get_keys() but the robust list
code has no alignment check in place.
As a consequence the kernel crashes on architectures with strict alignment
requirements in handle_futex_death() when trying to cmpxchg() on an
unaligned futex address which was retrieved from the robust list.
[ tglx: Rewrote changelog, proper sizeof() based alignement check and add
comment ]
Fixes: 0771dfefc9 ("[PATCH] lightweight robust futexes: core")
Signed-off-by: Chen Jie <chenjie6@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <dvhart@infradead.org>
Cc: <peterz@infradead.org>
Cc: <zengweilin@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1552621478-119787-1-git-send-email-chenjie6@huawei.com
Commit 7640ead939 ("bpf: verifier: make sure callees don't prune
with caller differences") connected up parentage chains of all
frames of the stack. It didn't, however, ensure propagate_liveness()
propagates all liveness information along those chains.
This means pruning happening in the callee may generate explored
states with incomplete liveness for the chains in lower frames
of the stack.
The included selftest is similar to the prior one from commit
7640ead939 ("bpf: verifier: make sure callees don't prune with
caller differences"), where callee would prune regardless of the
difference in r8 state.
Now we also initialize r9 to 0 or 1 based on a result from get_random().
r9 is never read so the walk with r9 = 0 gets pruned (correctly) after
the walk with r9 = 1 completes.
The selftest is so arranged that the pruning will happen in the
callee. Since callee does not propagate read marks of r8, the
explored state at the pruning point prior to the callee will
now ignore r8.
Propagate liveness on all frames of the stack when pruning.
Fixes: f4d7e40a5b ("bpf: introduce function calls (verification)")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Syzkaller hit 'KASAN: use-after-free Write in sanitize_ptr_alu' bug.
Call trace:
dump_stack+0xbf/0x12e
print_address_description+0x6a/0x280
kasan_report+0x237/0x360
sanitize_ptr_alu+0x85a/0x8d0
adjust_ptr_min_max_vals+0x8f2/0x1ca0
adjust_reg_min_max_vals+0x8ed/0x22e0
do_check+0x1ca6/0x5d00
bpf_check+0x9ca/0x2570
bpf_prog_load+0xc91/0x1030
__se_sys_bpf+0x61e/0x1f00
do_syscall_64+0xc8/0x550
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fault injection trace:
kfree+0xea/0x290
free_func_state+0x4a/0x60
free_verifier_state+0x61/0xe0
push_stack+0x216/0x2f0 <- inject failslab
sanitize_ptr_alu+0x2b1/0x8d0
adjust_ptr_min_max_vals+0x8f2/0x1ca0
adjust_reg_min_max_vals+0x8ed/0x22e0
do_check+0x1ca6/0x5d00
bpf_check+0x9ca/0x2570
bpf_prog_load+0xc91/0x1030
__se_sys_bpf+0x61e/0x1f00
do_syscall_64+0xc8/0x550
entry_SYSCALL_64_after_hwframe+0x49/0xbe
When kzalloc() fails in push_stack(), free_verifier_state() will free
current verifier state. As push_stack() returns, dst_reg was restored
if ptr_is_dst_reg is false. However, as member of the cur_state,
dst_reg is also freed, and error occurs when dereferencing dst_reg.
Simply fix it by testing ret of push_stack() before restoring dst_reg.
Fixes: 979d63d50c ("bpf: prevent out of bounds speculation on pointer arithmetic")
Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The recent change to prevent use after free and a memory leak introduced an
unconditional call to wq_unregister_lockdep() in the error handling
path. If the lockdep key had not been registered yet, then the lockdep core
emits a warning.
Only call wq_unregister_lockdep() if wq_register_lockdep() has been
called first.
Fixes: 009bb421b6 ("workqueue, lockdep: Fix an alloc_workqueue() error path")
Reported-by: syzbot+be0c198232f86389c3dd@syzkaller.appspotmail.com
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Link: https://lkml.kernel.org/r/20190311230255.176081-1-bvanassche@acm.org
Naresh reported that test_align fails because of the mismatch at the
verbose printout of the register states. The reason is due to the newly
added ref_obj_id.
ref_obj_id is only useful for refcounted reg. Thus, this patch fixes it
by only printing ref_obj_id for refcounted reg. While at it, it also uses
comma instead of space to separate between "id" and "ref_obj_id".
Fixes: 1b98658968 ("bpf: Fix bpf_tcp_sock and bpf_sk_fullsock issue related to bpf_sk_release")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The LLC NOHZ condition will become true as soon as >=2 CPUs in a
single LLC domain are busy. On big.LITTLE systems, this translates to
two or more CPUs of a "cluster" (big or LITTLE) being busy.
Issuing a NOHZ kick in these conditions isn't desired for asymmetric
systems, as if the busy CPUs can provide enough compute capacity to
the running tasks, then we can leave the NOHZ CPUs in peace.
Skip the LLC NOHZ condition for asymmetric systems, and rely on
nr_running & capacity checks to trigger NOHZ kicks when the system
actually needs them.
Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dietmar.Eggemann@arm.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20190211175946.4961-4-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In this commit:
3b1baa6496 ("sched/fair: Add 'group_misfit_task' load-balance type")
we set rq->misfit_task_load whenever the current running task has a
utilization greater than 80% of rq->cpu_capacity. A non-zero value in
this field enables misfit load balancing.
However, if the task being looked at is already running on a CPU of
highest capacity, there's nothing more we can do for it. We can
currently spot this in update_sd_pick_busiest(), which prevents us
from selecting a sched_group of group_type == group_misfit_task as the
busiest group, but we don't do any of that in nohz_balancer_kick().
This means that we could repeatedly kick NOHZ CPUs when there's no
improvements in terms of load balance to be done.
Introduce a check_misfit_status() helper that returns true iff there
is a CPU in the system that could give more CPU capacity to a rq's
misfit task - IOW, there exists a CPU of higher capacity_orig or the
rq's CPU is severely pressured by rt/IRQ.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dietmar.Eggemann@arm.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: morten.rasmussen@arm.com
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20190211175946.4961-3-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We now have a comment explaining the first sched_domain based NOHZ kick,
so might as well comment them all.
While at it, unwrap a line that fits under 80 characters.
Co-authored-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dietmar.Eggemann@arm.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: morten.rasmussen@arm.com
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20190211175946.4961-2-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Vincent Wang reported that get_next_freq() has a mult overflow bug on
32-bit platforms in the IOWAIT boost case, since in that case {util,max}
are in freq units instead of capacity units.
Solve this by moving the IOWAIT boost to capacity units. And since this
means @max is constant; simplify the code.
Reported-by: Vincent Wang <vincent.wang@unisoc.com>
Tested-by: Vincent Wang <vincent.wang@unisoc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190305083202.GU32494@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It has been observed that sometimes a higher order memory allocation
for BPF maps fails when there is no obvious memory pressure in a system.
E.g. the map (BPF_MAP_TYPE_LRU_HASH, key=38, value=56, max_elems=524288)
could not be created due to vmalloc unable to allocate 75497472B,
when the system's memory consumption (in MB) was the following:
Total: 3942 Used: 837 (21.24%) Free: 138 Buffers: 239 Cached: 2727
Later analysis [1] by Michal Hocko showed that the vmalloc was not trying
to reclaim memory from the page cache and was failing prematurely due to
__GFP_NORETRY.
Considering dcda9b0471 ("mm, tree wide: replace __GFP_REPEAT by
__GFP_RETRY_MAYFAIL with more useful semantic") and [1], we can replace
__GFP_NORETRY with __GFP_RETRY_MAYFAIL, as it won't invoke OOM killer
and will try harder to fulfil allocation requests.
Unfortunately, replacing the body of the BPF map memory allocation
function with the kvmalloc_node helper function is not an option at
this point in time, given 1) kmalloc is non-optional for higher order
allocations, and 2) passing __GFP_RETRY_MAYFAIL to the kmalloc would
stress the slab allocator too much for large requests.
The change has been tested with the workloads mentioned above and by
observing oom_kill value from /proc/vmstat.
[1]: https://lore.kernel.org/bpf/20190310071318.GW5232@dhcp22.suse.cz/
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Yonghong Song <yhs@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20190318153940.GL8924@dhcp22.suse.cz/
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Merge tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd system call from Christian Brauner:
"This introduces the ability to use file descriptors from /proc/<pid>/
as stable handles on struct pid. Even if a pid is recycled the handle
will not change. For a start these fds can be used to send signals to
the processes they refer to.
With the ability to use /proc/<pid> fds as stable handles on struct
pid we can fix a long-standing issue where after a process has exited
its pid can be reused by another process. If a caller sends a signal
to a reused pid it will end up signaling the wrong process.
With this patchset we enable a variety of use cases. One obvious
example is that we can now safely delegate an important part of
process management - sending signals - to processes other than the
parent of a given process by sending file descriptors around via scm
rights and not fearing that the given process will have been recycled
in the meantime. It also allows for easy testing whether a given
process is still alive or not by sending signal 0 to a pidfd which is
quite handy.
There has been some interest in this feature e.g. from systems
management (systemd, glibc) and container managers. I have requested
and gotten comments from glibc to make sure that this syscall is
suitable for their needs as well. In the future I expect it to take on
most other pid-based signal syscalls. But such features are left for
the future once they are needed.
This has been sitting in linux-next for quite a while and has not
caused any issues. It comes with selftests which verify basic
functionality and also test that a recycled pid cannot be signaled via
a pidfd.
Jon has written about a prior version of this patchset. It should
cover the basic functionality since not a lot has changed since then:
https://lwn.net/Articles/773459/
The commit message for the syscall itself is extensively documenting
the syscall, including it's functionality and extensibility"
* tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
selftests: add tests for pidfd_send_signal()
signal: add pidfd_send_signal() syscall
