tracing: Use the return of str_has_prefix() to remove open coded numbers
There are several locations that compare constants to the beginning of
string variables to determine what commands should be done, then the
constant length is used to index into the string. This is error prone as the
hard coded numbers have to match the size of the constants. Instead, use the
len returned from str_has_prefix() and remove the open coded string length
sizes.
Cc: Joe Perches <joe@perches.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> (for trace_probe part) Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
tracing: Use str_has_prefix() instead of using fixed sizes
There are several instances of strncmp(str, "const", 123), where 123 is the
strlen of the const string to check if "const" is the prefix of str. But
this can be error prone. Use str_has_prefix() instead.
Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
tracing: Use str_has_prefix() helper for histogram code
The tracing histogram code contains a lot of instances of the construct:
strncmp(str, "const", sizeof("const") - 1)
This can be prone to bugs due to typos or bad cut and paste. Use the
str_has_prefix() helper macro instead that removes the need for having two
copies of the constant string.
Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
A discussion came up in the trace triggers thread about converting a
bunch of:
strncmp(str, "const", sizeof("const") - 1)
use cases into a helper macro. It started with:
strncmp(str, const, sizeof(const) - 1)
But then Joe Perches mentioned that if a const is not used, the
sizeof() will be the size of a pointer, which can be bad. And that
gcc will optimize strlen("const") into "sizeof("const") - 1".
Thinking about this more, a quick grep in the kernel tree found several
(thousands!) of cases that use this construct. A quick grep also
revealed that there's probably several bugs in that use case. Some are
that people forgot the "- 1" (which I found) and others could be that
the constant for the sizeof is different than the constant (although, I
haven't found any of those, but I also didn't look hard).
I figured the best thing to do is to create a helper macro and place it
into include/linux/string.h. And go around and fix all the open coded
versions of it later.
Note, gcc appears to optimize this when we make it into an always_inline
static function, which removes a lot of issues that a macro produces.
In commit afaaf2d7af5d ("tracing: Add hook to function tracing for other
subsystems to use"), a new function ‘ftrace_exports’ was added. Since
this function can be made static, make it so.
Silence the following warning triggered using W=1:
kernel/trace/trace.c:2451:6: warning: no previous prototype for ‘ftrace_exports’ [-Wmissing-prototypes]
Rasmus Villemoes [Mon, 29 Oct 2018 22:35:42 +0000 (23:35 +0100)]
tracing: Simplify printf'ing in seq_print_sym
trace_seq_printf(..., "%s", ...) can be done with trace_seq_puts()
instead, avoiding printf overhead. In the second instance, the string
we're copying was just created from an snprintf() to a stack buffer, so
we might as well do that printf directly. This naturally leads to moving
the declaration of the str buffer inside the CONFIG_KALLSYMS guard,
which in turn will make gcc inline the function for !CONFIG_KALLSYMS (it
only has a single caller, but the huge stack frame seems to make gcc not
inline it for CONFIG_KALLSYMS).
Rasmus Villemoes [Mon, 29 Oct 2018 22:35:41 +0000 (23:35 +0100)]
tracing: Avoid -Wformat-nonliteral warning
Building with -Wformat-nonliteral, gcc complains
kernel/trace/trace_output.c: In function ‘seq_print_sym’:
kernel/trace/trace_output.c:356:3: warning: format not a string literal, argument types not checked [-Wformat-nonliteral]
trace_seq_printf(s, fmt, name);
But seq_print_sym only has a single caller which passes "%s" as fmt, so
we might as well just use that directly. That also paves the way for
further cleanups that will actually make that format string go away
entirely.
Tom Zanussi [Tue, 18 Dec 2018 20:33:24 +0000 (14:33 -0600)]
tracing: Use hist trigger's var_ref array to destroy var_refs
Since every var ref for a trigger has an entry in the var_ref[] array,
use that to destroy the var_refs, instead of piecemeal via the field
expressions.
This allows us to avoid having to keep and treat differently separate
lists for the action-related references, which future patches will
remove.
Tom Zanussi [Tue, 18 Dec 2018 20:33:23 +0000 (14:33 -0600)]
tracing: Remove open-coding of hist trigger var_ref management
Have create_var_ref() manage the hist trigger's var_ref list, rather
than having similar code doing it in multiple places. This cleans up
the code and makes sure var_refs are always accounted properly.
Also, document the var_ref-related functions to make what their
purpose clearer.
Tom Zanussi [Wed, 19 Dec 2018 19:09:16 +0000 (13:09 -0600)]
tracing: Use var_refs[] for hist trigger reference checking
Since all the variable reference hist_fields are collected into
hist_data->var_refs[] array, there's no need to go through all the
fields looking for them, or in separate arrays like synth_var_refs[],
which will be going away soon anyway.
This also allows us to get rid of some unnecessary code and functions
currently used for the same purpose.
Link: http://lkml.kernel.org/r/1545246556.4239.7.camel@gmail.com Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
tracing: Fix ftrace_graph_get_ret_stack() to use task and not current
The function ftrace_graph_get_ret_stack() takes a task struct descriptor but
uses current as the task to perform the operations on. In pretty much all
cases the task decriptor is the same as current, so this wasn't an issue.
But there is a case in the ARM architecture that passes in a task that is
not current, and expects a result from that task, and this code breaks it.
Fixes: 51584396cff5 ("arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack") Reported-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Michael Ellerman [Fri, 19 Oct 2018 04:21:09 +0000 (15:21 +1100)]
seq_buf: Use size_t for len in seq_buf_puts()
Jann Horn points out that we're using unsigned int for len in
seq_buf_puts(), which could potentially overflow if we're passed a
UINT_MAX sized string.
The rest of the code already uses size_t, so we should also use that
in seq_buf_puts() to avoid any issues.
Michael Ellerman [Fri, 19 Oct 2018 04:21:08 +0000 (15:21 +1100)]
seq_buf: Make seq_buf_puts() null-terminate the buffer
Currently seq_buf_puts() will happily create a non null-terminated
string for you in the buffer. This is particularly dangerous if the
buffer is on the stack.
arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack
The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.
Cc: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
sh: ftrace: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack
The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.
Cc: linux-sh@vger.kernel.org Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
sparc64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack
The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.
Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
powerpc/frace: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack
The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@lists.ozlabs.org Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
x86/ftrace: Do not call function graph from dynamic trampolines
Since commit eb1f7da1226ce ("ftrace: Optimize function graph to be
called directly"), dynamic trampolines should not be calling the
function graph tracer at the end. If they do, it could cause the function
graph tracer to trace functions that it filtered out.
Right now it does not cause a problem because there's a test to check if
the function graph tracer is attached to the same function as the
function tracer, which for now is true. But the function graph tracer is
undergoing changes that can make this no longer true which will cause
the function graph tracer to trace other functions.
fgraph: Add comment to describe ftrace_graph_get_ret_stack
The ret_stack should not be accessed directly via the curr_ret_stack
variable on the task_struct. This is because the ret_stack is going to be
converted into a series of longs and not an array of ret_stack structures.
The way that a ret_stack should be retrieved is via the
ftrace_graph_get_ret_stack structure, but it needs to be documented on how
to use it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
arm64: ftrace: Set FTRACE_MAY_SLEEP before ftrace_modify_all_code()
It has been reported that ftrace_replace_code() which is called by
ftrace_modify_all_code() can cause a soft lockup warning for an
allmodconfig kernel. This is because all the debug options enabled
causes the loop in ftrace_replace_code() (which loops over all the
functions being enabled where there can be 10s of thousands), is too
slow, and never schedules out.
To solve this, setting FTRACE_MAY_SLEEP to the command passed into
ftrace_replace_code() will make it call cond_resched() in the loop,
which prevents the soft lockup warning from triggering.
ftrace: Allow ftrace_replace_code() to be schedulable
The function ftrace_replace_code() is the ftrace engine that does the
work to modify all the nops into the calls to the function callback in
all the functions being traced.
The generic version which is normally called from stop machine, but an
architecture can implement a non stop machine version and still use the
generic ftrace_replace_code(). When an architecture does this,
ftrace_replace_code() may be called from a schedulable context, where
it can allow the code to be preemptible, and schedule out.
In order to allow an architecture to make ftrace_replace_code()
schedulable, a new command flag is added called:
FTRACE_MAY_SLEEP
Which can be or'd to the command that is passed to
ftrace_modify_all_code() that calls ftrace_replace_code() and will have
it call cond_resched() in the loop that modifies the nops into the
calls to the ftrace trampolines.
tracing: Add generic event-name based remove event method
Add a generic method to remove event from dynamic event
list. This is same as other system under ftrace. You
just need to pass the event name with '!', e.g.
tracing: Consolidate trace_add/remove_event_call back to the nolock functions
The trace_add/remove_event_call_nolock() functions were added to allow
the tace_add/remove_event_call() code be called when the event_mutex
lock was already taken. Now that all callers are done within the
event_mutex, there's no reason to have two different interfaces.
Remove the current wrapper trace_add/remove_event_call()s and rename the
_nolock versions back to the original names.
Rmove unneeded synth_event_mutex. This mutex protects the reference
count in synth_event, however, those operational points are already
protected by event_mutex.
1. In __create_synth_event() and create_or_delete_synth_event(),
those synth_event_mutex clearly obtained right after event_mutex.
2. event_hist_trigger_func() is trigger_hist_cmd.func() which is
called by trigger_process_regex(), which is a part of
event_trigger_regex_write() and this function takes event_mutex.
3. hist_unreg_all() is trigger_hist_cmd.unreg_all() which is called
by event_trigger_regex_open() and it takes event_mutex.
4. onmatch_destroy() and onmatch_create() have long call tree,
but both are finally invoked from event_trigger_regex_write()
and event_trace_del_tracer(), former takes event_mutex, and latter
ensures called under event_mutex locked.
Finally, I ensured there is no resource conflict. For safety,
I added lockdep_assert_held(&event_mutex) for each function.
Link: http://lkml.kernel.org/r/154140864134.17322.4796059721306031894.stgit@devbox Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
tracing: Use dyn_event framework for synthetic events
Use dyn_event framework for synthetic events. This shows
synthetic events on "tracing/dynamic_events" file in addition
to tracing/synthetic_events interface.
User can also define new events via tracing/dynamic_events
with "s:" prefix. So, the new syntax is below;
s:[synthetic/]EVENT_NAME TYPE ARG; [TYPE ARG;]...
To remove events via tracing/dynamic_events, you can use
"-:" prefix as same as other events.
tracing/uprobes: Use dyn_event framework for uprobe events
Use dyn_event framework for uprobe events. This shows
uprobe events on "dynamic_events" file.
User can also define new uprobe events via dynamic_events.
Link: http://lkml.kernel.org/r/154140858481.17322.9091293846515154065.stgit@devbox Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add unified dynamic event framework for ftrace kprobes, uprobes
and synthetic events. Those dynamic events can be co-exist on
same file because those syntax doesn't overlap.
This introduces a framework part which provides a unified tracefs
interface and operations.
tracing: Simplify creation and deletion of synthetic events
Since the event_mutex and synth_event_mutex ordering issue
is gone, we can skip existing event check when adding or
deleting events, and some redundant code in error path.
This changes release_all_synth_events() to abort the process
when it hits any error and returns the error code. It succeeds
only if it has no error.
On the other hand, synthetic event creation and deletion paths
call trace_add_event_call() and trace_remove_event_call()
which acquires event_mutex. In that case, if we keep the
synth_event_mutex locked while registering/unregistering synthetic
events, its dependency will be inversed.
To avoid this issue, current synthetic event is using a 2 phase
process to create/delete events. For example, it searches existing
events under synth_event_mutex to check for event-name conflicts, and
unlocks synth_event_mutex, then registers a new event under event_mutex
locked. Finally, it locks synth_event_mutex and tries to add the
new event to the list. But it can introduce complexity and a chance
for name conflicts.
To solve this simpler, this introduces trace_add_event_call_nolock()
and trace_remove_event_call_nolock() which don't acquire
event_mutex inside. synthetic event can lock event_mutex before
synth_event_mutex to solve the lock dependency issue simpler.
tracing/uprobes: Add busy check when cleanup all uprobes
Add a busy check loop in cleanup_all_probes() before
trying to remove all events in uprobe_events, the same way
that kprobe_events does.
Without this change, writing null to uprobe_events will
try to remove events but if one of them is enabled, it will
stop there leaving some events cleared and others not clceared.
With this change, writing null to uprobe_events makes
sure all events are not enabled before removing events.
So, it clears all events, or returns an error (-EBUSY)
with keeping all events.
After running several tests, it appears that having the reader wait till
half the buffer is full before starting to read (and causing its own events
to fill up the ring buffer constantly), works well. It keeps trace-cmd (the
main user of this interface) from dominating the traces it records.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add a "buffer_percentage" file, that allows users to specify how much of the
buffer (percentage of pages) need to be filled before waking up a task
blocked on a per cpu trace_pipe_raw file.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
ring-buffer: Add percentage of ring buffer full to wake up reader
Instead of just waiting for a page to be full before waking up a pending
reader, allow the reader to pass in a "percentage" of pages that have
content before waking up a reader. This should help keep the process of
reading the events not cause wake ups that constantly cause reading of the
buffer.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Joe Lawrence [Tue, 20 Nov 2018 20:19:18 +0000 (15:19 -0500)]
scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names
When building with -ffunction-sections, the compiler will place each
function into its own ELF section, prefixed with ".text". For example,
a simple test module with functions test_module_do_work() and
test_module_wq_func():
Adjust the recordmcount scripts to look for ".text" as a section name
prefix. This will ensure that those functions will be included in the
__mcount_loc relocations:
% objdump --reloc --section __mcount_loc test_module.o
OFFSET TYPE VALUE 0000000000000000 R_X86_64_64 .text.test_module_do_work 0000000000000008 R_X86_64_64 .text.test_module_wq_func 0000000000000010 R_X86_64_64 .init.text
Dan Carpenter [Wed, 20 Jun 2018 11:08:00 +0000 (14:08 +0300)]
tracing: Have trace_stack nr_entries compare not be so subtle
Dan Carpenter reviewed the trace_stack.c code and figured he found an off by
one bug.
"From reviewing the code, it seems possible for
stack_trace_max.nr_entries to be set to .max_entries and in that case we
would be reading one element beyond the end of the stack_dump_trace[]
array. If it's not set to .max_entries then the bug doesn't affect
runtime."
Although it looks to be the case, it is not. Because we have:
stack_trace_max.nr_entries = x;
for (; x < i; x++)
stack_dump_trace[x] = ULONG_MAX;
Even if nr_entries equals max_entries, indexing with it into the
stack_dump_trace[] array will not overflow the array. But if it is the case,
the second part of the conditional that tests stack_dump_trace[nr_entries]
to ULONG_MAX will always be true.
By applying Dan's patch, it removes the subtle aspect of it and makes the if
conditional slightly more efficient.
function_graph: Have profiler use new helper ftrace_graph_get_ret_stack()
The ret_stack processing is going to change, and that is going
to break anything that is accessing the ret_stack directly. One user is the
function graph profiler. By using the ftrace_graph_get_ret_stack() helper
function, the profiler can access the ret_stack entry without relying on the
implementation details of the stack itself.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
function_graph: Move ftrace_graph_ret_addr() to fgraph.c
Move the function function_graph_ret_addr() to fgraph.c, as the management
of the curr_ret_stack is going to change, and all the accesses to ret_stack
needs to be done in fgraph.c.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
fgraph: Add new fgraph_ops structure to enable function graph hooks
Currently the registering of function graph is to pass in a entry and return
function. We need to have a way to associate those functions together where
the entry can determine to run the return hook. Having a structure that
contains both functions will facilitate the process of converting the code
to be able to do such.
This is similar to the way function hooks are enabled (it passes in
ftrace_ops). Instead of passing in the functions to use, a single structure
is passed in to the registering function.
The unregister function is now passed in the fgraph_ops handle. When we
allow more than one callback to the function graph hooks, this will let the
system know which one to remove.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
tracing: Rearrange functions in trace_sched_wakeup.c
Rearrange the functions in trace_sched_wakeup.c so that there are fewer
#ifdef CONFIG_FUNCTION_TRACER and #ifdef CONFIG_FUNCTION_GRAPH_TRACER,
instead of having the #ifdefs spread all over.
No functional change is made.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
fgraph: Move function graph specific code into fgraph.c
To make the function graph infrastructure more managable, the code needs to
be in its own file (fgraph.c). Move the code that is specific for managing
the function graph infrastructure out of ftrace.c and into fgraph.c
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
function_graph: Do not expose the graph_time option when profiler is not configured
When the function profiler is not configured, the "graph_time" option is
meaningless, as the function profiler is the only thing that makes use of
it. Do not expose it if the profiler is not configured.
In order to move function graph infrastructure into its own file (fgraph.h)
it needs to access various functions and variables in ftrace.c that are
currently static. Create a new file called ftrace-internal.h that holds the
function prototypes and the extern declarations of the variables needed by
fgraph.c as well, and make them global in ftrace.c such that they can be
used outside that file.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
function_graph: Remove the use of FTRACE_NOTRACE_DEPTH
The curr_ret_stack is no longer set to a negative value when a function is
not to be traced by the function graph tracer. Remove the usage of
FTRACE_NOTRACE_DEPTH, as it is no longer needed.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
arm64: function_graph: Remove use of FTRACE_NOTRACE_DEPTH
Functions in the set_graph_notrace no longer subtract FTRACE_NOTRACE_DEPTH
from curr_ret_stack, as that is now implemented via the trace_recursion
flags. Access to curr_ret_stack no longer needs to worry about checking for
this. curr_ret_stack is still initialized to -1, when there's not a shadow
stack allocated.
Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: linux-arm-kernel@lists.infradead.org Acked-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
fgraph: Have set_graph_notrace only affect function_graph tracer
In order to make the function graph infrastructure more generic, there can
not be code specific for the function_graph tracer in the generic code. This
includes the set_graph_notrace logic, that stops all graph calls when a
function in the set_graph_notrace is hit.
By using the trace_recursion mask, we can use a bit in the current
task_struct to implement the notrace code, and move the logic out of
fgraph.c and into trace_functions_graph.c and keeps it affecting only the
tracer and not all call graph callbacks.
Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
fgraph: Create a fgraph.c file to store function graph infrastructure
As the function graph infrastructure can be used by thing other than
tracing, moving the code to its own file out of the trace_functions_graph.c
code makes more sense.
The fgraph.c file will only contain the infrastructure required to hook into
functions and their return code.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
tracing: Do not line wrap short line in function_graph_enter()
Commit 588ca1786f2dd ("function_graph: Use new curr_ret_depth to manage
depth instead of curr_ret_stack") removed a parameter from the call
ftrace_push_return_trace() that made it so that the entire call was under 80
characters, but it did not remove the line break. There's no reason to break
that line up, so make it a single line.
tracing/fgraph: Fix set_graph_function from showing interrupts
The tracefs file set_graph_function is used to only function graph functions
that are listed in that file (or all functions if the file is empty). The
way this is implemented is that the function graph tracer looks at every
function, and if the current depth is zero and the function matches
something in the file then it will trace that function. When other functions
are called, the depth will be greater than zero (because the original
function will be at depth zero), and all functions will be traced where the
depth is greater than zero.
The issue is that when a function is first entered, and the handler that
checks this logic is called, the depth is set to zero. If an interrupt comes
in and a function in the interrupt handler is traced, its depth will be
greater than zero and it will automatically be traced, even if the original
function was not. But because the logic only looks at depth it may trace
interrupts when it should not be.
The recent design change of the function graph tracer to fix other bugs
caused the depth to be zero while the function graph callback handler is
being called for a longer time, widening the race of this happening. This
bug was actually there for a longer time, but because the race window was so
small it seldom happened. The Fixes tag below is for the commit that widen
the race window, because that commit belongs to a series that will also help
fix the original bug.
Cc: stable@kernel.org Fixes: 53e9842d5852 ("function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack") Reported-by: Joe Lawrence <joe.lawrence@redhat.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Zenghui Yu [Wed, 28 Nov 2018 03:35:23 +0000 (03:35 +0000)]
tracepoint: Use __idx instead of idx in DO_TRACE macro to make it unique
After enabling KVM event tracing, almost all of trace_kvm_exit()'s
printk shows
"kvm_exit: IRQ: ..."
even if the actual exception_type is NOT IRQ. More specifically,
trace_kvm_exit() is defined in virt/kvm/arm/trace.h by TRACE_EVENT.
This slight problem may have existed after commit 0d8d748d710b
("tracepoint: Make rcuidle tracepoint callers use SRCU"). There are
two variables in trace_kvm_exit() and __DO_TRACE() which have the
same name, *idx*. Thus the actual value of *idx* will be overwritten
when tracing. Fix it by adding a simple prefix.
Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Wang Haibin <wanghaibin.wang@huawei.com> Cc: linux-trace-devel@vger.kernel.org Cc: stable@vger.kernel.org Fixes: 0d8d748d710b ("tracepoint: Make rcuidle tracepoint callers use SRCU") Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
sched, trace: Fix prev_state output in sched_switch tracepoint
commit 7573e93b16d7 ("sched/debug: Fix task state recording/printout")
tried to fix the problem introduced by a previous commit 56fc8c129e3a
("sched/tracing: Fix trace_sched_switch task-state printing"). However
the prev_state output in sched_switch is still broken.
task_state_index() uses fls() which considers the LSB as 1. Left
shifting 1 by this value gives an incorrect mapping to the task state.
Fix this by decrementing the value returned by __get_task_state()
before shifting.
function_graph: Have profiler use curr_ret_stack and not depth
The profiler uses trace->depth to find its entry on the ret_stack, but the
depth may not match the actual location of where its entry is (if an
interrupt were to preempt the processing of the profiler for another
function, the depth and the curr_ret_stack will be different).
Have it use the curr_ret_stack as the index to find its ret_stack entry
instead of using the depth variable, as that is no longer guaranteed to be
the same.
function_graph: Reverse the order of pushing the ret_stack and the callback
The function graph profiler uses the ret_stack to store the "subtime" and
reuse it by nested functions and also on the return. But the current logic
has the profiler callback called before the ret_stack is updated, and it is
just modifying the ret_stack that will later be allocated (it's just lucky
that the "subtime" is not touched when it is allocated).
This could also cause a crash if we are at the end of the ret_stack when
this happens.
By reversing the order of the allocating the ret_stack and then calling the
callbacks attached to a function being traced, the ret_stack entry is no
longer used before it is allocated.
function_graph: Move return callback before update of curr_ret_stack
In the past, curr_ret_stack had two functions. One was to denote the depth
of the call graph, the other is to keep track of where on the ret_stack the
data is used. Although they may be slightly related, there are two cases
where they need to be used differently.
The one case is that it keeps the ret_stack data from being corrupted by an
interrupt coming in and overwriting the data still in use. The other is just
to know where the depth of the stack currently is.
The function profiler uses the ret_stack to save a "subtime" variable that
is part of the data on the ret_stack. If curr_ret_stack is modified too
early, then this variable can be corrupted.
The "max_depth" option, when set to 1, will record the first functions going
into the kernel. To see all top functions (when dealing with timings), the
depth variable needs to be lowered before calling the return hook. But by
lowering the curr_ret_stack, it makes the data on the ret_stack still being
used by the return hook susceptible to being overwritten.
Now that there's two variables to handle both cases (curr_ret_depth), we can
move them to the locations where they can handle both cases.
function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack
Currently, the depth of the ret_stack is determined by curr_ret_stack index.
The issue is that there's a race between setting of the curr_ret_stack and
calling of the callback attached to the return of the function.
Commit 7e2f56662a14 ("tracing/fgraph: Adjust fgraph depth before calling
trace return callback") moved the calling of the callback to after the
setting of the curr_ret_stack, even stating that it was safe to do so, when
in fact, it was the reason there was a barrier() there (yes, I should have
commented that barrier()).
Not only does the curr_ret_stack keep track of the current call graph depth,
it also keeps the ret_stack content from being overwritten by new data.
The function profiler, uses the "subtime" variable of ret_stack structure
and by moving the curr_ret_stack, it allows for interrupts to use the same
structure it was using, corrupting the data, and breaking the profiler.
To fix this, there needs to be two variables to handle the call stack depth
and the pointer to where the ret_stack is being used, as they need to change
at two different locations.
function_graph: Make ftrace_push_return_trace() static
As all architectures now call function_graph_enter() to do the entry work,
no architecture should ever call ftrace_push_return_trace(). Make it static.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
sparc/function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have sparc use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: "David S. Miller" <davem@davemloft.net> Cc: sparclinux@vger.kernel.org Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
sh/function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have superh use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
s390/function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have s390 use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
riscv/function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have riscv use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Greentime Hu <greentime@andestech.com> Cc: Alan Kao <alankao@andestech.com> Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Palmer Dabbelt <palmer@sifive.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
powerpc/function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have powerpc use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
parisc: function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have parisc use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
nds32: function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have nds32 use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Greentime Hu <greentime@andestech.com> Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
MIPS: function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have MIPS use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
microblaze: function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have microblaze use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Michal Simek <monstr@monstr.eu> Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
arm64: function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have arm64 use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
ARM: function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have ARM use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Russell King <linux@armlinux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Cc: stable@kernel.org Fixes: 7e2f56662a145 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
x86/function_graph: Simplify with function_graph_enter()
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have x86 use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
function_graph: Create function_graph_enter() to consolidate architecture code
Currently all the architectures do basically the same thing in preparing the
function graph tracer on entry to a function. This code can be pulled into a
generic location and then this will allow the function graph tracer to be
fixed, as well as extended.
Create a new function graph helper function_graph_enter() that will call the
hook function (ftrace_graph_entry) and the shadow stack operation
(ftrace_push_return_trace), and remove the need of the architecture code to
manage the shadow stack.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Linus Torvalds [Sun, 18 Nov 2018 20:21:09 +0000 (12:21 -0800)]
Merge tag 'libnvdimm-fixes-4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm fixes from Dan Williams:
"A small batch of fixes for v4.20-rc3.
The overflow continuation fix addresses something that has been broken
for several releases. Arguably it could wait even longer, but it's a
one line fix and this finishes the last of the known address range
scrub bug reports. The revert addresses a lockdep regression. The unit
tests are not critical to fix, but no reason to hold this fix back.
Summary:
- Address Range Scrub overflow continuation handling has been broken
since it was initially merged. It was only recently that error
injection and platform-BIOS support enabled this corner case to be
exercised.
- The recent attempt to provide more isolation for the kernel Address
Range Scrub state machine from userapace initiated sessions
triggers a lockdep report. Revert and try again at the next merge
window.
- Fix a kasan reported buffer overflow in libnvdimm unit test
infrastrucutre (nfit_test)"
* tag 'libnvdimm-fixes-4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
Revert "acpi, nfit: Further restrict userspace ARS start requests"
acpi, nfit: Fix ARS overflow continuation
tools/testing/nvdimm: Fix the array size for dimm devices.
Linus Torvalds [Sun, 18 Nov 2018 19:31:26 +0000 (11:31 -0800)]
Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
"16 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm/memblock.c: fix a typo in __next_mem_pfn_range() comments
mm, page_alloc: check for max order in hot path
scripts/spdxcheck.py: make python3 compliant
tmpfs: make lseek(SEEK_DATA/SEK_HOLE) return ENXIO with a negative offset
lib/ubsan.c: don't mark __ubsan_handle_builtin_unreachable as noreturn
mm/vmstat.c: fix NUMA statistics updates
mm/gup.c: fix follow_page_mask() kerneldoc comment
ocfs2: free up write context when direct IO failed
scripts/faddr2line: fix location of start_kernel in comment
mm: don't reclaim inodes with many attached pages
mm, memory_hotplug: check zone_movable in has_unmovable_pages
mm/swapfile.c: use kvzalloc for swap_info_struct allocation
MAINTAINERS: update OMAP MMC entry
hugetlbfs: fix kernel BUG at fs/hugetlbfs/inode.c:444!
kernel/sched/psi.c: simplify cgroup_move_task()
z3fold: fix possible reclaim races
Linus Torvalds [Sun, 18 Nov 2018 18:58:20 +0000 (10:58 -0800)]
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
"Fix an exec() related scalability/performance regression, which was
caused by incorrectly calculating load and migrating tasks on exec()
when they shouldn't be"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix cpu_util_wake() for 'execl' type workloads
Linus Torvalds [Sun, 18 Nov 2018 18:54:59 +0000 (10:54 -0800)]
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Fix uncore PMU enumeration for CofeeLake CPUs"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/uncore: Support CoffeeLake 8th CBOX
perf/x86/intel/uncore: Add more IMC PCI IDs for KabyLake and CoffeeLake CPUs
Linus Torvalds [Sun, 18 Nov 2018 18:52:26 +0000 (10:52 -0800)]
Merge branch 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI fixes from Ingo Molnar:
"Misc fixes: two warning splat fixes, a leak fix and persistent memory
allocation fixes for ARM"
* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi: Permit calling efi_mem_reserve_persistent() from atomic context
efi/arm: Defer persistent reservations until after paging_init()
efi/arm/libstub: Pack FDT after populating it
efi/arm: Revert deferred unmap of early memmap mapping
efi: Fix debugobjects warning on 'efi_rts_work'
Linus Torvalds [Sun, 18 Nov 2018 18:45:09 +0000 (10:45 -0800)]
Merge branch 'spectre' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM spectre updates from Russell King:
"These are the currently known final bits that resolve the Spectre
issues. big.Little systems used to be sufficiently identical in that
there were no differences between individual CPUs in the system that
mattered to the kernel. With the advent of the Spectre problem, the
CPUs now have differences in how the workaround is applied.
As a result of previous Spectre patches, these systems ended up
reporting quite a lot of:
"CPUx: Spectre v2: incorrect context switching function, system vulnerable"
messages due to the action of the big.Little switcher causing the CPUs
to be re-initialised regularly. This series resolves that issue by
making the CPU vtable unique to each CPU.
However, since this is used very early, before per-cpu is setup,
per-cpu can't be used. We also have a problem that two of the methods
are not called from preempt-safe paths, but thankfully these remain
identical between all CPUs in the system. To make sure, we validate
that these are identical during boot"
* 'spectre' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: spectre-v2: per-CPU vtables to work around big.Little systems
ARM: add PROC_VTABLE and PROC_TABLE macros
ARM: clean up per-processor check_bugs method call
ARM: split out processor lookup
ARM: make lookup_processor_type() non-__init
the problem is that we only check for an out of bound order in the slow
path and the node reclaim might happen from the fast path already. This
is fixable by making sure that kvmalloc doesn't ever use kmalloc for
requests that are larger than KMALLOC_MAX_SIZE but this also shows that
the code is rather fragile. A recent UBSAN report just underlines that
by the following report
Note that this is not a kvmalloc path. It is just that the fast path
really depends on having sanitzed order as well. Therefore move the
order check to the fast path.
Link: http://lkml.kernel.org/r/20181113094305.GM15120@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reported-by: Kyungtae Kim <kt0755@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Byoungyoung Lee <lifeasageek@gmail.com> Cc: "Dae R. Jeong" <threeearcat@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Uwe Kleine-König [Fri, 16 Nov 2018 23:08:43 +0000 (15:08 -0800)]
scripts/spdxcheck.py: make python3 compliant
Without this change the following happens when using Python3 (3.6.6):
$ echo "GPL-2.0" | python3 scripts/spdxcheck.py -
FAIL: 'str' object has no attribute 'decode'
Traceback (most recent call last):
File "scripts/spdxcheck.py", line 253, in <module>
parser.parse_lines(sys.stdin, args.maxlines, '-')
File "scripts/spdxcheck.py", line 171, in parse_lines
line = line.decode(locale.getpreferredencoding(False), errors='ignore')
AttributeError: 'str' object has no attribute 'decode'
So as the line is already a string, there is no need to decode it and
the line can be dropped.
/usr/bin/python on Arch is Python 3. So this would indeed be worth
going into 4.19.
Link: http://lkml.kernel.org/r/20181023070802.22558-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Joe Perches <joe@perches.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yufen Yu [Fri, 16 Nov 2018 23:08:39 +0000 (15:08 -0800)]
tmpfs: make lseek(SEEK_DATA/SEK_HOLE) return ENXIO with a negative offset
Other filesystems such as ext4, f2fs and ubifs all return ENXIO when
lseek (SEEK_DATA or SEEK_HOLE) requests a negative offset.
man 2 lseek says
: EINVAL whence is not valid. Or: the resulting file offset would be
: negative, or beyond the end of a seekable device.
:
: ENXIO whence is SEEK_DATA or SEEK_HOLE, and the file offset is beyond
: the end of the file.
Make tmpfs return ENXIO under these circumstances as well. After this,
tmpfs also passes xfstests's generic/448.
[akpm@linux-foundation.org: rewrite changelog] Link: http://lkml.kernel.org/r/1540434176-14349-1-git-send-email-yuyufen@huawei.com Signed-off-by: Yufen Yu <yuyufen@huawei.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Arnd Bergmann [Fri, 16 Nov 2018 23:08:35 +0000 (15:08 -0800)]
lib/ubsan.c: don't mark __ubsan_handle_builtin_unreachable as noreturn
gcc-8 complains about the prototype for this function:
lib/ubsan.c:432:1: error: ignoring attribute 'noreturn' in declaration of a built-in function '__ubsan_handle_builtin_unreachable' because it conflicts with attribute 'const' [-Werror=attributes]
This is actually a GCC's bug. In GCC internals
__ubsan_handle_builtin_unreachable() declared with both 'noreturn' and
'const' attributes instead of only 'noreturn':
Janne Huttunen [Fri, 16 Nov 2018 23:08:32 +0000 (15:08 -0800)]
mm/vmstat.c: fix NUMA statistics updates
Scan through the whole array to see if an update is needed. While we're
at it, use sizeof() to be safe against any possible type changes in the
future.
The bug here is that we wouldn't sync per-cpu counters into global ones
if there was an update of numa_stats for higher cpus. Highly
theoretical one though because it is much more probable that zone_stats
are updated so we would refresh anyway. So I wouldn't bother to mark
this for stable, yet something nice to fix.
[mhocko@suse.com: changelog enhancement] Link: http://lkml.kernel.org/r/1541601517-17282-1-git-send-email-janne.huttunen@nokia.com Fixes: 276a77e43d19 ("mm: update NUMA counter threshold size") Signed-off-by: Janne Huttunen <janne.huttunen@nokia.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 3b26eddf2d06 ("mm/gup: cache dev_pagemap while pinning pages")
modified the signature of follow_page_mask() but left the parameter
description behind.
Update the description to make the code and comments agree again.
While at it, update formatting of the return value description to match
Documentation/doc-guide/kernel-doc.rst guidelines.
Wengang Wang [Fri, 16 Nov 2018 23:08:25 +0000 (15:08 -0800)]
ocfs2: free up write context when direct IO failed
The write context should also be freed even when direct IO failed.
Otherwise a memory leak is introduced and entries remain in
oi->ip_unwritten_list causing the following BUG later in unlink path:
Roman Gushchin [Fri, 16 Nov 2018 23:08:18 +0000 (15:08 -0800)]
mm: don't reclaim inodes with many attached pages
Spock reported that commit d11df0151322 ("mm: slowly shrink slabs with a
relatively small number of objects") leads to a regression on his setup:
periodically the majority of the pagecache is evicted without an obvious
reason, while before the change the amount of free memory was balancing
around the watermark.
The reason behind is that the mentioned above change created some
minimal background pressure on the inode cache. The problem is that if
an inode is considered to be reclaimed, all belonging pagecache page are
stripped, no matter how many of them are there. So, if a huge
multi-gigabyte file is cached in the memory, and the goal is to reclaim
only few slab objects (unused inodes), we still can eventually evict all
gigabytes of the pagecache at once.
The workload described by Spock has few large non-mapped files in the
pagecache, so it's especially noticeable.
To solve the problem let's postpone the reclaim of inodes, which have
more than 1 attached page. Let's wait until the pagecache pages will be
evicted naturally by scanning the corresponding LRU lists, and only then
reclaim the inode structure.
Link: http://lkml.kernel.org/r/20181023164302.20436-1-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Reported-by: Spock <dairinin@gmail.com> Tested-by: Spock <dairinin@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: <stable@vger.kernel.org> [4.19.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Fri, 16 Nov 2018 23:08:15 +0000 (15:08 -0800)]
mm, memory_hotplug: check zone_movable in has_unmovable_pages
Page state checks are racy. Under a heavy memory workload (e.g. stress
-m 200 -t 2h) it is quite easy to hit a race window when the page is
allocated but its state is not fully populated yet. A debugging patch to
dump the struct page state shows
Note that the state has been checked for both PageLRU and PageSwapBacked
already. Closing this race completely would require some sort of retry
logic. This can be tricky and error prone (think of potential endless
or long taking loops).
Workaround this problem for movable zones at least. Such a zone should
only contain movable pages. Commit 852ae9513e49 ("mm, memory_hotplug:
make has_unmovable_pages more robust") has told us that this is not
strictly true though. Bootmem pages should be marked reserved though so
we can move the original check after the PageReserved check. Pages from
other zones are still prone to races but we even do not pretend that
memory hotremove works for those so pre-mature failure doesn't hurt that
much.
Link: http://lkml.kernel.org/r/20181106095524.14629-1-mhocko@kernel.org Fixes: 852ae9513e49 ("mm, memory_hotplug: make has_unmovable_pages more robust") Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Baoquan He <bhe@redhat.com> Tested-by: Baoquan He <bhe@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vasily Averin [Fri, 16 Nov 2018 23:08:11 +0000 (15:08 -0800)]
mm/swapfile.c: use kvzalloc for swap_info_struct allocation
Commit b86aaba4df26 ("swap: choose swap device according to numa node")
changed 'avail_lists' field of 'struct swap_info_struct' to an array.
In popular linux distros it increased size of swap_info_struct up to 40
Kbytes and now swap_info_struct allocation requires order-4 page.
Switch to kvzmalloc allows to avoid unexpected allocation failures.
Link: http://lkml.kernel.org/r/fc23172d-3c75-21e2-d551-8b1808cbe593@virtuozzo.com Fixes: b86aaba4df26 ("swap: choose swap device according to numa node") Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Acked-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Huang Ying <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Aaro Koskinen [Fri, 16 Nov 2018 23:08:08 +0000 (15:08 -0800)]
MAINTAINERS: update OMAP MMC entry
Jarkko's e-mail address hasn't worked for a long time. We still want to
keep this driver working as it is critical for some of the OMAP boards.
I use and test this driver frequently, so change myself as a maintainer
with "Odd Fixes" status.
Link: http://lkml.kernel.org/r/20181106222750.12939-1-aaro.koskinen@iki.fi Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Fri, 16 Nov 2018 23:08:04 +0000 (15:08 -0800)]
hugetlbfs: fix kernel BUG at fs/hugetlbfs/inode.c:444!
This bug has been experienced several times by the Oracle DB team. The
BUG is in remove_inode_hugepages() as follows:
/*
* If page is mapped, it was faulted in after being
* unmapped in caller. Unmap (again) now after taking
* the fault mutex. The mutex will prevent faults
* until we finish removing the page.
*
* This race can only happen in the hole punch case.
* Getting here in a truncate operation is a bug.
*/
if (unlikely(page_mapped(page))) {
BUG_ON(truncate_op);
In this case, the elevated map count is not the result of a race.
Rather it was incorrectly incremented as the result of a bug in the huge
pmd sharing code. Consider the following:
- Process A maps a hugetlbfs file of sufficient size and alignment
(PUD_SIZE) that a pmd page could be shared.
- Process B maps the same hugetlbfs file with the same size and
alignment such that a pmd page is shared.
- Process B then calls mprotect() to change protections for the mapping
with the shared pmd. As a result, the pmd is 'unshared'.
- Process B then calls mprotect() again to chage protections for the
mapping back to their original value. pmd remains unshared.
- Process B then forks and process C is created. During the fork
process, we do dup_mm -> dup_mmap -> copy_page_range to copy page
tables. Copying page tables for hugetlb mappings is done in the
routine copy_hugetlb_page_range.
In copy_hugetlb_page_range(), the destination pte is obtained by:
dst_pte = huge_pte_alloc(dst, addr, sz);
If pmd sharing is possible, the returned pointer will be to a pte in an
existing page table. In the situation above, process C could share with
either process A or process B. Since process A is first in the list,
the returned pte is a pointer to a pte in process A's page table.
However, the check for pmd sharing in copy_hugetlb_page_range is:
/* If the pagetables are shared don't copy or take references */
if (dst_pte == src_pte)
continue;
Since process C is sharing with process A instead of process B, the
above test fails. The code in copy_hugetlb_page_range which follows
assumes dst_pte points to a huge_pte_none pte. It copies the pte entry
from src_pte to dst_pte and increments this map count of the associated
page. This is how we end up with an elevated map count.
To solve, check the dst_pte entry for huge_pte_none. If !none, this
implies PMD sharing so do not copy.
Link: http://lkml.kernel.org/r/20181105212315.14125-1-mike.kravetz@oracle.com Fixes: e6532b8d838f ("fix hugepages leak due to pagetable page sharing") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Olof Johansson [Fri, 16 Nov 2018 23:08:00 +0000 (15:08 -0800)]
kernel/sched/psi.c: simplify cgroup_move_task()
The existing code triggered an invalid warning about 'rq' possibly being
used uninitialized. Instead of doing the silly warning suppression by
initializa it to NULL, refactor the code to bail out early instead.
Warning was:
kernel/sched/psi.c: In function `cgroup_move_task':
kernel/sched/psi.c:639:13: warning: `rq' may be used uninitialized in this function [-Wmaybe-uninitialized]
Link: http://lkml.kernel.org/r/20181103183339.8669-1-olof@lixom.net Fixes: 44083edf138ee ("psi: cgroup support") Signed-off-by: Olof Johansson <olof@lixom.net> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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