| Age | Commit message (Collapse) | Author | Files | Lines |
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Add kprobe_event= boot parameter to define kprobe events
at boot time.
The definition syntax is similar to tracefs/kprobe_events
interface, but use ',' and ';' instead of ' ' and '\n'
respectively. e.g.
kprobe_event=p,vfs_read,$arg1,$arg2
This puts a probe on vfs_read with argument1 and 2, and
enable the new event.
Link: http://lkml.kernel.org/r/155851395498.15728.830529496248543583.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Initialize kprobes at postcore_initcall level instead of module_init
since kprobes is not a module, and it depends on only subsystems
initialized in core_initcall.
This will allow ftrace kprobe event to add new events when it is
initializing because ftrace kprobe event is initialized at
later initcall level.
Link: http://lkml.kernel.org/r/155851394736.15728.13626739508905120098.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Cast user-space address correctly to pass to probe_user_read().
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The comment of trace_filter_add_remove_task() refers to the function as
'trace_pid_filter_add_remove_task', use the correct name.
Link: http://lkml.kernel.org/r/20190523192628.134406-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Support user-space dereference syntax for probe event arguments
to dereference the data-structure or array in user-space.
The syntax is just adding 'u' before an offset value.
+|-u<OFFSET>(<FETCHARG>)
e.g. +u8(%ax), +u0(+0(%si))
For example, if you probe do_sched_setscheduler(pid, policy,
param) and record param->sched_priority, you can add new
probe as below;
p do_sched_setscheduler priority=+u0($arg3)
Note that kprobe event provides this and it doesn't change the
dereference method automatically because we do not know whether
the given address is in userspace or kernel on some archs.
So as same as "ustring", this is an option for user, who has to
carefully choose the dereference method.
Link: http://lkml.kernel.org/r/155789872187.26965.4468456816590888687.stgit@devnote2
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add "ustring" type for fetching user-space string from kprobe event.
User can specify ustring type at uprobe event, and it is same as
"string" for uprobe.
Note that probe-event provides this option but it doesn't choose the
correct type automatically since we have not way to decide the address
is in user-space or not on some arch (and on some other arch, you can
fetch the string by "string" type). So user must carefully check the
target code (e.g. if you see __user on the target variable) and
use this new type.
Link: http://lkml.kernel.org/r/155789871009.26965.14167558859557329331.stgit@devnote2
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The code modification functions have "enable" and "update" variables that
are sometimes "int" but used as "bool". Remove the ambiguity and make them
"bool" when they are only used for true or false values.
Link: http://lkml.kernel.org/r/e1429923d9eda92a3cf5ee9e33c7eacce539781d.1558115654.git.naveen.n.rao@linux.vnet.ibm.com
Reported-by: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Starting with GCC 9, -Warray-bounds detects cases when memset is called
starting on a member of a struct but the size to be cleared ends up
writing over further members.
Such a call happens in the trace code to clear, at once, all members
after and including `seq` on struct trace_iterator:
In function 'memset',
inlined from 'ftrace_dump' at kernel/trace/trace.c:8914:3:
./include/linux/string.h:344:9: warning: '__builtin_memset' offset
[8505, 8560] from the object at 'iter' is out of the bounds of
referenced subobject 'seq' with type 'struct trace_seq' at offset
4368 [-Warray-bounds]
344 | return __builtin_memset(p, c, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
In order to avoid GCC complaining about it, we compute the address
ourselves by adding the offsetof distance instead of referring
directly to the member.
Since there are two places doing this clear (trace.c and trace_kdb.c),
take the chance to move the workaround into a single place in
the internal header.
Link: http://lkml.kernel.org/r/20190523124535.GA12931@gmail.com
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
[ Removed unnecessary parenthesis around "iter" ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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... and get rid of the weird dances in ->get_tree() - that logics
can be easily handled in ->init_fs_context().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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it's a no-op
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The sync_sched_exp_online_cleanup() is invoked at online time to handle
the case where the start of an expedited grace period ran concurrently
with a CPU being taken offline and then immediately being placed online.
It checks to see if RCU needs an expedited quiescent state from the
incoming CPU, sending it an IPI if so. However, it is quite possible
that sync_sched_exp_online_cleanup() is running on that CPU, in which
case it is considerably less overhead to simply request the quiescent
state locally instead of simulating a self-IPI.
This commit therefore places the last few lines of rcu_exp_handler()
into a new rcu_exp_need_qs() function, which is invoked both by
rcu_exp_handler() and by sync_sched_exp_online_cleanup() in the self-IPI
case.
This also reduces the rcu_exp_handler() function's state space by
removing the direct call that this smp_call_function_single() uses to
emulate the requested self-IPI. This in turn will allow tighter error
checking in rcu_is_cpu_rrupt_from_idle().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
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Although sync_rcu_exp_select_node_cpus() treats the current CPU as being
in a quiescent state, it might well migrate to some other CPU before
reaching the smp_call_function_single(), which could then result in an
unnecessary simulated self-IPI. This commit therefore instead simply
refuses to invoke smp_call_function_single() on the current CPU, which
causes the later rcu_report_exp_cpu_mult() to report this CPU's quiescent
state with less overhead.
This also reduces the rcu_exp_handler() function's state space by removing
the direct call that this smp_call_function_single() uses to emulate the
requested self-IPI.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
[ paulmck: Use get_cpu() instead of preempt_disable() per Joel Fernandes. ]
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This commit saves a few lines of code by inlining invoke_rcu_callbacks()
into its sole remaining caller.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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When rcu_read_unlock_special() is invoked with interrupts disabled, is
either not in an interrupt handler or is not using RCU_SOFTIRQ, is not
the first RCU read-side critical section in the chain, and either there
is an expedited grace period in flight or this is a NO_HZ_FULL kernel,
the end of the grace period can be unduly delayed. The reason for this
is that it is not safe to do wakeups in this situation.
This commit fixes this problem by using the irq_work subsystem to
force a later interrupt handler in a clean environment. Because
set_tsk_need_resched(current) and set_preempt_need_resched() are
invoked prior to this, the scheduler will force a context switch
upon return from this interrupt (though perhaps at the end of any
interrupted preempt-disable or BH-disable region of code), which will
invoke rcu_note_context_switch() (again in a clean environment), which
will in turn give RCU the chance to report the deferred quiescent state.
Of course, by then this task might be within another RCU read-side
critical section. But that will be detected at that time and reporting
will be further deferred to the outermost rcu_read_unlock(). See
rcu_preempt_need_deferred_qs() and rcu_preempt_deferred_qs() for more
details on the checking.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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When running in an interrupt handler, raise_softirq() and
raise_softirq_irqoff() have extremely low overhead: They simply set a
bit in a per-CPU mask, which is checked upon exit from that interrupt
handler. Therefore, if rcu_read_unlock_special() is invoked within an
interrupt handler and RCU_SOFTIRQ is in use, this commit make use of
raise_softirq_irqoff() even if there is no expedited grace period in
flight and even if this is not a nohz_full CPU.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Currently, rcu_read_unlock_special() will do wakeups whenever it is safe
to do so. However, wakeups are expensive, and they are only really
needed when the just-ended RCU read-side critical section is blocking
an expedited grace period (in which case speed is of the essence)
or on a nohz_full CPU (where it might be a good long time before an
interrupt arrives). This commit therefore checks for these conditions,
and does the expensive wakeups only if doing so would be useful.
Note it can be rather expensive to determine whether or not the current
task (as opposed to the current CPU) is blocking the current expedited
grace period. Doing so requires traversing the ->blkd_tasks list, which
can be quite long. This commit therefore cheats: If the current task
is on a given ->blkd_tasks list, and some task on that list is blocking
the current expedited grace period, the code assumes that the current
task is blocking that expedited grace period.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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When RCU core processing is offloaded from RCU_SOFTIRQ to the rcuc
kthreads, a full and unconditional wakeup is required to initiate RCU
core processing. In contrast, when RCU core processing is carried
out by RCU_SOFTIRQ, a raise_softirq() suffices. Of course, there are
situations where raise_softirq() does a full wakeup, but these do not
occur with normal usage of rcu_read_unlock().
The reason that full wakeups can be problematic is that the scheduler
sometimes invokes rcu_read_unlock() with its pi or rq locks held,
which can of course result in deadlock in CONFIG_PREEMPT=y kernels when
rcu_read_unlock() invokes the scheduler. Scheduler invocations can happen
in the following situations: (1) The just-ended reader has been subjected
to RCU priority boosting, in which case rcu_read_unlock() must deboost,
(2) Interrupts were disabled across the call to rcu_read_unlock(), so
the quiescent state must be deferred, requiring a wakeup of the rcuc
kthread corresponding to the current CPU.
Now, the scheduler may hold one of its locks across rcu_read_unlock()
only if preemption has been disabled across the entire RCU read-side
critical section, which in the days prior to RCU flavor consolidation
meant that rcu_read_unlock() never needed to do wakeups. However, this
is no longer the case for any but the first rcu_read_unlock() following a
condition (e.g., preempted RCU reader) requiring special rcu_read_unlock()
attention. For example, an RCU read-side critical section might be
preempted, but preemption might be disabled across the rcu_read_unlock().
The rcu_read_unlock() must defer the quiescent state, and therefore
leaves the task queued on its leaf rcu_node structure. If a scheduler
interrupt occurs, the scheduler might well invoke rcu_read_unlock() with
one of its locks held. However, the preempted task is still queued, so
rcu_read_unlock() will attempt to defer the quiescent state once more.
When RCU core processing is carried out by RCU_SOFTIRQ, this works just
fine: The raise_softirq() function simply sets a bit in a per-CPU mask
and the RCU core processing will be undertaken upon return from interrupt.
Not so when RCU core processing is carried out by the rcuc kthread: In this
case, the required wakeup can result in deadlock.
The initial solution to this problem was to use set_tsk_need_resched() and
set_preempt_need_resched() to force a future context switch, which allows
rcu_preempt_note_context_switch() to report the deferred quiescent state
to RCU's core processing. Unfortunately for expedited grace periods,
there can be a significant delay between the call for a context switch
and the actual context switch.
This commit therefore introduces a ->deferred_qs flag to the task_struct
structure's rcu_special structure. This flag is initially false, and
is set to true by the first call to rcu_read_unlock() requiring special
attention, then finally reset back to false when the quiescent state is
finally reported. Then rcu_read_unlock() attempts full wakeups only when
->deferred_qs is false, that is, on the first rcu_read_unlock() requiring
special attention. Note that a chain of RCU readers linked by some other
sort of reader may find that a later rcu_read_unlock() is once again able
to do a full wakeup, courtesy of an intervening preemption:
rcu_read_lock();
/* preempted */
local_irq_disable();
rcu_read_unlock(); /* Can do full wakeup, sets ->deferred_qs. */
rcu_read_lock();
local_irq_enable();
preempt_disable()
rcu_read_unlock(); /* Cannot do full wakeup, ->deferred_qs set. */
rcu_read_lock();
preempt_enable();
/* preempted, >deferred_qs reset. */
local_irq_disable();
rcu_read_unlock(); /* Can again do full wakeup, sets ->deferred_qs. */
Such linked RCU readers do not yet seem to appear in the Linux kernel, and
it is probably best if they don't. However, RCU needs to handle them, and
some variations on this theme could make even raise_softirq() unsafe due to
the possibility of its doing a full wakeup. This commit therefore also
avoids invoking raise_softirq() when the ->deferred_qs set flag is set.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Some workloads need to change kthread priority for RCU core processing
without affecting other softirq work. This commit therefore introduces
the rcutree.use_softirq kernel boot parameter, which moves the RCU core
work from softirq to a per-CPU SCHED_OTHER kthread named rcuc. Use of
SCHED_OTHER approach avoids the scalability problems that appeared
with the earlier attempt to move RCU core processing to from softirq
to kthreads. That said, kernels built with RCU_BOOST=y will run the
rcuc kthreads at the RCU-boosting priority.
Note that rcutree.use_softirq=0 must be specified to move RCU core
processing to the rcuc kthreads: rcutree.use_softirq=1 is the default.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ paulmck: Adjust for invoke_rcu_callbacks() only ever being invoked
from RCU core processing, in contrast to softirq->rcuc transition
in old mainline RCU priority boosting. ]
[ paulmck: Avoid wakeups when scheduler might have invoked rcu_read_unlock()
while holding rq or pi locks, also possibly fixing a pre-existing latent
bug involving raise_softirq()-induced wakeups. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Tom Zanussi sent me some small fixes and cleanups to the histogram
code and I forgot to incorporate them.
I also added a small clean up patch that was sent to me a while ago
and I just noticed it"
* tag 'trace-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
kernel/trace/trace.h: Remove duplicate header of trace_seq.h
tracing: Add a check_val() check before updating cond_snapshot() track_val
tracing: Check keys for variable references in expressions too
tracing: Prevent hist_field_var_ref() from accessing NULL tracing_map_elts
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This patch randomizes high 32-bit of a definition when BPF_F_TEST_RND_HI32
is set.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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x86_64 and AArch64 perhaps are two arches that running bpf testsuite
frequently, however the zero extension insertion pass is not enabled for
them because of their hardware support.
It is critical to guarantee the pass correction as it is supposed to be
enabled at default for a couple of other arches, for example PowerPC,
SPARC, arm, NFP etc. Therefore, it would be very useful if there is a way
to test this pass on for example x86_64.
The test methodology employed by this set is "poisoning" useless bits. High
32-bit of a definition is randomized if it is identified as not used by any
later insn. Such randomization is only enabled under testing mode which is
gated by the new bpf prog load flags "BPF_F_TEST_RND_HI32".
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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After previous patches, verifier will mark a insn if it really needs zero
extension on dst_reg.
It is then for back-ends to decide how to use such information to eliminate
unnecessary zero extension code-gen during JIT compilation.
One approach is verifier insert explicit zero extension for those insns
that need zero extension in a generic way, JIT back-ends then do not
generate zero extension for sub-register write at default.
However, only those back-ends which do not have hardware zero extension
want this optimization. Back-ends like x86_64 and AArch64 have hardware
zero extension support that the insertion should be disabled.
This patch introduces new target hook "bpf_jit_needs_zext" which returns
false at default, meaning verifier zero extension insertion is disabled at
default. A back-end could override this hook to return true if it doesn't
have hardware support and want verifier insert zero extension explicitly.
Offload targets do not use this native target hook, instead, they could
get the optimization results using bpf_prog_offload_ops.finalize.
NOTE: arches could have diversified features, it is possible for one arch
to have hardware zero extension support for some sub-register write insns
but not for all. For example, PowerPC, SPARC have zero extended loads, but
not for alu32. So when verifier zero extension insertion enabled, these JIT
back-ends need to peephole insns to remove those zero extension inserted
for insn that actually has hardware zero extension support. The peephole
could be as simple as looking the next insn, if it is a special zero
extension insn then it is safe to eliminate it if the current insn has
hardware zero extension support.
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Patched insns do not go through generic verification, therefore doesn't has
zero extension information collected during insn walking.
We don't bother analyze them at the moment, for any sub-register def comes
from them, just conservatively mark it as needing zero extension.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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eBPF ISA specification requires high 32-bit cleared when low 32-bit
sub-register is written. This applies to destination register of ALU32 etc.
JIT back-ends must guarantee this semantic when doing code-gen. x86_64 and
AArch64 ISA has the same semantics, so the corresponding JIT back-end
doesn't need to do extra work.
However, 32-bit arches (arm, x86, nfp etc.) and some other 64-bit arches
(PowerPC, SPARC etc) need to do explicit zero extension to meet this
requirement, otherwise code like the following will fail.
u64_value = (u64) u32_value
... other uses of u64_value
This is because compiler could exploit the semantic described above and
save those zero extensions for extending u32_value to u64_value, these JIT
back-ends are expected to guarantee this through inserting extra zero
extensions which however could be a significant increase on the code size.
Some benchmarks show there could be ~40% sub-register writes out of total
insns, meaning at least ~40% extra code-gen.
One observation is these extra zero extensions are not always necessary.
Take above code snippet for example, it is possible u32_value will never be
casted into a u64, the value of high 32-bit of u32_value then could be
ignored and extra zero extension could be eliminated.
This patch implements this idea, insns defining sub-registers will be
marked when the high 32-bit of the defined sub-register matters. For
those unmarked insns, it is safe to eliminate high 32-bit clearnace for
them.
Algo:
- Split read flags into READ32 and READ64.
- Record index of insn that does sub-register write. Keep the index inside
reg state and update it during verifier insn walking.
- A full register read on a sub-register marks its definition insn as
needing zero extension on dst register.
A new sub-register write overrides the old one.
- When propagating read64 during path pruning, also mark any insn defining
a sub-register that is read in the pruned path as full-register.
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pule more SPDX updates from Greg KH:
"Here is another set of reviewed patches that adds SPDX tags to
different kernel files, based on a set of rules that are being used to
parse the comments to try to determine that the license of the file is
"GPL-2.0-or-later".
Only the "obvious" versions of these matches are included here, a
number of "non-obvious" variants of text have been found but those
have been postponed for later review and analysis.
These patches have been out for review on the linux-spdx@vger mailing
list, and while they were created by automatic tools, they were
hand-verified by a bunch of different people, all whom names are on
the patches are reviewers"
* tag 'spdx-5.2-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (85 commits)
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 125
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 123
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 122
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 121
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 120
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 119
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 118
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 116
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 114
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 113
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 112
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 111
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 110
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 106
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 105
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 103
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 102
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 101
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 98
...
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This patch tries to solve the following specific use case.
Currently, bpf program can already collect stack traces
through kernel function get_perf_callchain()
when certain events happens (e.g., cache miss counter or
cpu clock counter overflows). But such stack traces are
not enough for jitted programs, e.g., hhvm (jited php).
To get real stack trace, jit engine internal data structures
need to be traversed in order to get the real user functions.
bpf program itself may not be the best place to traverse
the jit engine as the traversing logic could be complex and
it is not a stable interface either.
Instead, hhvm implements a signal handler,
e.g. for SIGALARM, and a set of program locations which
it can dump stack traces. When it receives a signal, it will
dump the stack in next such program location.
Such a mechanism can be implemented in the following way:
. a perf ring buffer is created between bpf program
and tracing app.
. once a particular event happens, bpf program writes
to the ring buffer and the tracing app gets notified.
. the tracing app sends a signal SIGALARM to the hhvm.
But this method could have large delays and causing profiling
results skewed.
This patch implements bpf_send_signal() helper to send
a signal to hhvm in real time, resulting in intended stack traces.
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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The kernel test robot has reported that the use of __this_cpu_add()
causes bug messages like:
BUG: using __this_cpu_add() in preemptible [00000000] code: ...
Given the imprecise nature of the count and the possibility of resetting
the count and doing the measurement again, this is not really a big
problem to use the unprotected __this_cpu_*() functions.
To make the preemption checking code happy, the this_cpu_*() functions
will be used if CONFIG_DEBUG_PREEMPT is defined.
The imprecise nature of the locking counts are also documented with
the suggestion that we should run the measurement a few times with the
counts reset in between to get a better picture of what is going on
under the hood.
Fixes: a8654596f0371 ("locking/rwsem: Enable lock event counting")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus reported an issue that doing an allmodconfig was causing the
kheaders archive to be regenerated even though the config is the same.
This patch fixes the issue by ignoring the config-related header files
for "knowing when to regenerate based on timestamps". Instead, if the
CONFIG_X_Y option really changes, then we there are the
include/config/X/Y.h which will already tells us "if a config really
changed". So we don't really need these files for regeneration detection
anyway, and ignoring them fixes Linus's issue.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The kheaders archive consisting of the kernel headers used for compiling
bpf programs is in /proc. However there is concern that moving it here
will make it permanent. Let us move it to /sys/kernel as discussed [1].
[1] https://lore.kernel.org/patchwork/patch/1067310/#1265969
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Based on 1 normalized pattern(s):
this file is released under the gplv2 and any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.732920462@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public licence as published by
the free software foundation either version 2 of the licence or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 114 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
gcc warns that function print_lock_trace() is unused if
CONFIG_PROVE_LOCKING isn't set:
../kernel/locking/lockdep.c:2820:13: warning: ‘print_lock_trace’ defined but not used [-Wunused-function]
Rework so we remove the function if CONFIG_PROVE_LOCKING isn't set.
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: will.deacon@arm.com
Fixes: c120bce78065 ("lockdep: Simplify stack trace handling")
Link: http://lkml.kernel.org/r/20190516191326.27003-1-anders.roxell@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
While the IRQ/NMI will nest, the nest-count will be invariant over the
actual exception, since it will decrement equal to increment.
This means we can -- carefully -- use a regular variable since the
typical LOAD-STORE race doesn't exist (similar to preempt_count).
This optimizes the ring-buffer for all LOAD-STORE architectures, since
they need to use atomic ops to implement local_t.
Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: mark.rutland@arm.com
Cc: namhyung@kernel.org
Cc: yabinc@google.com
Link: http://lkml.kernel.org/r/20190517115418.481392777@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
We must use {READ,WRITE}_ONCE() on rb->user_page data such that
concurrent usage will see whole values. A few key sites were missing
this.
Suggested-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: mark.rutland@arm.com
Cc: namhyung@kernel.org
Fixes: 7b732a750477 ("perf_counter: new output ABI - part 1")
Link: http://lkml.kernel.org/r/20190517115418.394192145@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Similar to how decrementing rb->next too early can cause data_head to
(temporarily) be observed to go backward, so too can this happen when
we increment too late.
This barrier() ensures the rb->head load happens after the increment,
both the one in the 'goto again' path, as the one from
perf_output_get_handle() -- albeit very unlikely to matter for the
latter.
Suggested-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: mark.rutland@arm.com
Cc: namhyung@kernel.org
Fixes: ef60777c9abd ("perf: Optimize the perf_output() path by removing IRQ-disables")
Link: http://lkml.kernel.org/r/20190517115418.309516009@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
In perf_output_put_handle(), an IRQ/NMI can happen in below location and
write records to the same ring buffer:
...
local_dec_and_test(&rb->nest)
... <-- an IRQ/NMI can happen here
rb->user_page->data_head = head;
...
In this case, a value A is written to data_head in the IRQ, then a value
B is written to data_head after the IRQ. And A > B. As a result,
data_head is temporarily decreased from A to B. And a reader may see
data_head < data_tail if it read the buffer frequently enough, which
creates unexpected behaviors.
This can be fixed by moving dec(&rb->nest) to after updating data_head,
which prevents the IRQ/NMI above from updating data_head.
[ Split up by peterz. ]
Signed-off-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: mark.rutland@arm.com
Fixes: ef60777c9abd ("perf: Optimize the perf_output() path by removing IRQ-disables")
Link: http://lkml.kernel.org/r/20190517115418.224478157@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
It is possible to ignore the validation for a certain lock by using:
lockdep_set_novalidate_class()
on it. Each invocation will assign a new name to the class it created
for created __lockdep_no_validate__. That means that once
lockdep_set_novalidate_class() has been used on two locks then
class->name won't match lock->name for the first lock triggering the
warning.
So ignore changed non-matching ->name pointer for the special
__lockdep_no_validate__ class.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20190517212234.32611-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Provide a method to filter out sockaddr and bind calls by network
address family.
Existing SOCKADDR records are listed for any network activity.
Implement the AUDIT_SADDR_FAM field selector to be able to classify or
limit records to specific network address families, such as AF_INET or
AF_INET6.
An example of a network record that is unlikely to be useful and flood
the logs:
type=SOCKADDR msg=audit(07/27/2017 12:18:27.019:845) : saddr={ fam=local
path=/var/run/nscd/socket }
type=SYSCALL msg=audit(07/27/2017 12:18:27.019:845) : arch=x86_64
syscall=connect success=no exit=ENOENT(No such file or directory) a0=0x3
a1=0x7fff229c4980 a2=0x6e a3=0x6 items=1 ppid=3301 pid=6145 auid=sgrubb
uid=sgrubb gid=sgrubb euid=sgrubb suid=sgrubb fsuid=sgrubb egid=sgrubb
sgid=sgrubb fsgid=sgrubb tty=pts3 ses=4 comm=bash exe=/usr/bin/bash
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
key=network-test
Please see the audit-testsuite PR at
https://github.com/linux-audit/audit-testsuite/pull/87
Please see the github issue
https://github.com/linux-audit/audit-kernel/issues/64
Please see the github issue for the accompanying userspace support
https://github.com/linux-audit/audit-userspace/issues/93
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: merge fuzz in auditfilter.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Multiple checks were being done in one switch case statement that
started to cause some redundancies and awkward exceptions. Separate the
valid field and op check from the select valid values checks.
Enforce the elimination of meaningless bitwise and greater/lessthan
checks on string fields and other fields with unrelated scalar values.
Please see the github issue
https://github.com/linux-audit/audit-kernel/issues/73
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
All prune points inside a callee bpf function most likely will have
different callsites. For example, if function foo() is called from
two callsites the half of explored states in all prune points in foo()
will be useless for subsequent walking of one of those callsites.
Fortunately explored_states pruning heuristics keeps the number of states
per prune point small, but walking these states is still a waste of cpu
time when the callsite of the current state is different from the callsite
of the explored state.
To improve pruning logic convert explored_states into hash table and
use simple insn_idx ^ callsite hash to select hash bucket.
This optimization has no effect on programs without bpf2bpf calls
and drastically improves programs with calls.
In the later case it reduces total memory consumption in 1M scale tests
by almost 3 times (peak_states drops from 5752 to 2016).
Care should be taken when comparing the states for equivalency.
Since the same hash bucket can now contain states with different indices
the insn_idx has to be part of verifier_state and compared.
Different hash table sizes and different hash functions were explored,
but the results were not significantly better vs this patch.
They can be improved in the future.
Hit/miss heuristic is not counting index miscompare as a miss.
Otherwise verifier stats become unstable when experimenting
with different hash functions.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
split explored_states into prune_point boolean mark
and link list of explored states.
This removes STATE_LIST_MARK hack and allows marks to be separate from states.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
clean up explored_states to prep for introduction of hashtable
No functional changes.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
The limit of 1024 subsequent jumps was causing otherwise valid
programs to be rejected. Bump it to 8192 and make the error more verbose.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
The function send_signal was split from __send_signal so that it would
be possible to bypass the namespace logic based upon current[1]. As it
turns out the si_pid and the si_uid fixup are both inappropriate in
the case of kill_pid_usb_asyncio so move that logic into send_signal.
It is difficult to arrange but possible for a signal with an si_code
of SI_TIMER or SI_SIGIO to be sent across namespace boundaries. In
which case tests for when it is ok to change si_pid and si_uid based
on SI_FROMUSER are incorrect. Replace the use of SI_FROMUSER with a
new test has_si_pid_and_used based on siginfo_layout.
Now that the uid fixup is no longer present after expanding
SEND_SIG_NOINFO properly calculate the si_uid that the target
task needs to read.
[1] 7978b567d315 ("signals: add from_ancestor_ns parameter to send_signal()")
Cc: stable@vger.kernel.org
Fixes: 6588c1e3ff01 ("signals: SI_USER: Masquerade si_pid when crossing pid ns boundary")
Fixes: 6b550f949594 ("user namespace: make signal.c respect user namespaces")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The usb support for asyncio encoded one of it's values in the wrong
field. It should have used si_value but instead used si_addr which is
not present in the _rt union member of struct siginfo.
The practical result of this is that on a 64bit big endian kernel
when delivering a signal to a 32bit process the si_addr field
is set to NULL, instead of the expected pointer value.
This issue can not be fixed in copy_siginfo_to_user32 as the usb
usage of the the _sigfault (aka si_addr) member of the siginfo
union when SI_ASYNCIO is set is incompatible with the POSIX and
glibc usage of the _rt member of the siginfo union.
Therefore replace kill_pid_info_as_cred with kill_pid_usb_asyncio a
dedicated function for this one specific case. There are no other
users of kill_pid_info_as_cred so this specialization should have no
impact on the amount of code in the kernel. Have kill_pid_usb_asyncio
take instead of a siginfo_t which is difficult and error prone, 3
arguments, a signal number, an errno value, and an address enconded as
a sigval_t. The encoding of the address as a sigval_t allows the
code that reads the userspace request for a signal to handle this
compat issue along with all of the other compat issues.
Add BUILD_BUG_ONs in kernel/signal.c to ensure that we can now place
the pointer value at the in si_pid (instead of si_addr). That is the
code now verifies that si_pid and si_addr always occur at the same
location. Further the code veries that for native structures a value
placed in si_pid and spilling into si_uid will appear in userspace in
si_addr (on a byte by byte copy of siginfo or a field by field copy of
siginfo). The code also verifies that for a 64bit kernel and a 32bit
userspace the 32bit pointer will fit in si_pid.
I have used the usbsig.c program below written by Alan Stern and
slightly tweaked by me to run on a big endian machine to verify the
issue exists (on sparc64) and to confirm the patch below fixes the issue.
/* usbsig.c -- test USB async signal delivery */
#define _GNU_SOURCE
#include <stdio.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <endian.h>
#include <linux/usb/ch9.h>
#include <linux/usbdevice_fs.h>
static struct usbdevfs_urb urb;
static struct usbdevfs_disconnectsignal ds;
static volatile sig_atomic_t done = 0;
void urb_handler(int sig, siginfo_t *info , void *ucontext)
{
printf("Got signal %d, signo %d errno %d code %d addr: %p urb: %p\n",
sig, info->si_signo, info->si_errno, info->si_code,
info->si_addr, &urb);
printf("%s\n", (info->si_addr == &urb) ? "Good" : "Bad");
}
void ds_handler(int sig, siginfo_t *info , void *ucontext)
{
printf("Got signal %d, signo %d errno %d code %d addr: %p ds: %p\n",
sig, info->si_signo, info->si_errno, info->si_code,
info->si_addr, &ds);
printf("%s\n", (info->si_addr == &ds) ? "Good" : "Bad");
done = 1;
}
int main(int argc, char **argv)
{
char *devfilename;
int fd;
int rc;
struct sigaction act;
struct usb_ctrlrequest *req;
void *ptr;
char buf[80];
if (argc != 2) {
fprintf(stderr, "Usage: usbsig device-file-name\n");
return 1;
}
devfilename = argv[1];
fd = open(devfilename, O_RDWR);
if (fd == -1) {
perror("Error opening device file");
return 1;
}
act.sa_sigaction = urb_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
rc = sigaction(SIGUSR1, &act, NULL);
if (rc == -1) {
perror("Error in sigaction");
return 1;
}
act.sa_sigaction = ds_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
rc = sigaction(SIGUSR2, &act, NULL);
if (rc == -1) {
perror("Error in sigaction");
return 1;
}
memset(&urb, 0, sizeof(urb));
urb.type = USBDEVFS_URB_TYPE_CONTROL;
urb.endpoint = USB_DIR_IN | 0;
urb.buffer = buf;
urb.buffer_length = sizeof(buf);
urb.signr = SIGUSR1;
req = (struct usb_ctrlrequest *) buf;
req->bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
req->bRequest = USB_REQ_GET_DESCRIPTOR;
req->wValue = htole16(USB_DT_DEVICE << 8);
req->wIndex = htole16(0);
req->wLength = htole16(sizeof(buf) - sizeof(*req));
rc = ioctl(fd, USBDEVFS_SUBMITURB, &urb);
if (rc == -1) {
perror("Error in SUBMITURB ioctl");
return 1;
}
rc = ioctl(fd, USBDEVFS_REAPURB, &ptr);
if (rc == -1) {
perror("Error in REAPURB ioctl");
return 1;
}
memset(&ds, 0, sizeof(ds));
ds.signr = SIGUSR2;
ds.context = &ds;
rc = ioctl(fd, USBDEVFS_DISCSIGNAL, &ds);
if (rc == -1) {
perror("Error in DISCSIGNAL ioctl");
return 1;
}
printf("Waiting for usb disconnect\n");
while (!done) {
sleep(1);
}
close(fd);
return 0;
}
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.com>
Fixes: v2.3.39
Cc: stable@vger.kernel.org
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Remove duplicate header which is included twice.
Link: http://lkml.kernel.org/r/1553725186-41442-1-git-send-email-jagdsh.linux@gmail.com
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Jagadeesh Pagadala <jagdsh.linux@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Sparse warnings are incurred by key_fs[ug]id_changed() due to unprotected
accesses of tsk->cred, which is marked __rcu.
Fix this by passing the new cred struct to these functions from
commit_creds() rather than the task pointer.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
|
|
When a process signals the audit daemon (shutdown, rotate, resume,
reconfig) but syscall auditing is not enabled, we still want to know the
identity of the process sending the signal to the audit daemon.
Move audit_signal_info() out of syscall auditing to general auditing but
create a new function audit_signal_info_syscall() to take care of the
syscall dependent parts for when syscall auditing is enabled.
Please see the github kernel audit issue
https://github.com/linux-audit/audit-kernel/issues/111
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull SPDX update from Greg KH:
"Here is a series of patches that add SPDX tags to different kernel
files, based on two different things:
- SPDX entries are added to a bunch of files that we missed a year
ago that do not have any license information at all.
These were either missed because the tool saw the MODULE_LICENSE()
tag, or some EXPORT_SYMBOL tags, and got confused and thought the
file had a real license, or the files have been added since the
last big sweep, or they were Makefile/Kconfig files, which we
didn't touch last time.
- Add GPL-2.0-only or GPL-2.0-or-later tags to files where our scan
tools can determine the license text in the file itself. Where this
happens, the license text is removed, in order to cut down on the
700+ different ways we have in the kernel today, in a quest to get
rid of all of these.
These patches have been out for review on the linux-spdx@vger mailing
list, and while they were created by automatic tools, they were
hand-verified by a bunch of different people, all whom names are on
the patches are reviewers.
The reason for these "large" patches is if we were to continue to
progress at the current rate of change in the kernel, adding license
tags to individual files in different subsystems, we would be finished
in about 10 years at the earliest.
There will be more series of these types of patches coming over the
next few weeks as the tools and reviewers crunch through the more
"odd" variants of how to say "GPLv2" that developers have come up with
over the years, combined with other fun oddities (GPL + a BSD
disclaimer?) that are being unearthed, with the goal for the whole
kernel to be cleaned up.
These diffstats are not small, 3840 files are touched, over 10k lines
removed in just 24 patches"
* tag 'spdx-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (24 commits)
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 24
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 23
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 22
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 21
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 20
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 19
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 18
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 17
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 15
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 14
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 12
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 11
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 10
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 7
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 5
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 4
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 3
...
|
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Without this check a snapshot is taken whenever a bucket's max is hit,
rather than only when the global max is hit, as it should be.
Before:
In this example, we do a first run of the workload (cyclictest),
examine the output, note the max ('triggering value') (347), then do
a second run and note the max again.
In this case, the max in the second run (39) is below the max in the
first run, but since we haven't cleared the histogram, the first max
is still in the histogram and is higher than any other max, so it
should still be the max for the snapshot. It isn't however - the
value should still be 347 after the second run.
# echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmax($wakeup_lat).save(next_prio,next_comm,prev_pid,prev_prio,prev_comm):onmax($wakeup_lat).snapshot() if next_comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
# cyclictest -p 80 -n -s -t 2 -D 2
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
{ next_pid: 2143 } hitcount: 199
max: 44 next_prio: 120 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/4
{ next_pid: 2145 } hitcount: 1325
max: 38 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/2
{ next_pid: 2144 } hitcount: 1982
max: 347 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/6
Snapshot taken (see tracing/snapshot). Details:
triggering value { onmax($wakeup_lat) }: 347
triggered by event with key: { next_pid: 2144 }
# cyclictest -p 80 -n -s -t 2 -D 2
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
{ next_pid: 2143 } hitcount: 199
max: 44 next_prio: 120 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/4
{ next_pid: 2148 } hitcount: 199
max: 16 next_prio: 120 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/1
{ next_pid: 2145 } hitcount: 1325
max: 38 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/2
{ next_pid: 2150 } hitcount: 1326
max: 39 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/4
{ next_pid: 2144 } hitcount: 1982
max: 347 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/6
{ next_pid: 2149 } hitcount: 1983
max: 130 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/0
Snapshot taken (see tracing/snapshot). Details:
triggering value { onmax($wakeup_lat) }: 39
triggered by event with key: { next_pid: 2150 }
After:
In this example, we do a first run of the workload (cyclictest),
examine the output, note the max ('triggering value') (375), then do
a second run and note the max again.
In this case, the max in the second run is still 375, the highest in
any bucket, as it should be.
# cyclictest -p 80 -n -s -t 2 -D 2
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
{ next_pid: 2072 } hitcount: 200
max: 28 next_prio: 120 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/5
{ next_pid: 2074 } hitcount: 1323
max: 375 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/2
{ next_pid: 2073 } hitcount: 1980
max: 153 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/6
Snapshot taken (see tracing/snapshot). Details:
triggering value { onmax($wakeup_lat) }: 375
triggered by event with key: { next_pid: 2074 }
# cyclictest -p 80 -n -s -t 2 -D 2
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
{ next_pid: 2101 } hitcount: 199
max: 49 next_prio: 120 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/6
{ next_pid: 2072 } hitcount: 200
max: 28 next_prio: 120 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/5
{ next_pid: 2074 } hitcount: 1323
max: 375 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/2
{ next_pid: 2103 } hitcount: 1325
max: 74 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/4
{ next_pid: 2073 } hitcount: 1980
max: 153 next_prio: 19 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/6
{ next_pid: 2102 } hitcount: 1981
max: 84 next_prio: 19 next_comm: cyclictest
prev_pid: 12 prev_prio: 120 prev_comm: kworker/0:1
Snapshot taken (see tracing/snapshot). Details:
triggering value { onmax($wakeup_lat) }: 375
triggered by event with key: { next_pid: 2074 }
Link: http://lkml.kernel.org/r/95958351329f129c07504b4d1769c47a97b70d65.1555597045.git.tom.zanussi@linux.intel.com
Cc: stable@vger.kernel.org
Fixes: a3785b7eca8fd ("tracing: Add hist trigger snapshot() action")
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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