- Hide get_vm_area() from MMUless builds
The function get_vm_area() is not defined when CONFIG_MMU is not defined.
Hide that function within #ifdef CONFIG_MMU.
- Fix output of synthetic events when they have dynamic strings
The print fmt of the synthetic event's format file use to have "%.*s" for
dynamic size strings even though the user space exported arguments had
only __get_str() macro that provided just a nul terminated string. This
was fixed so that user space could parse this properly. But the reason
that it had "%.*s" was because internally it provided the maximum size of
the string as one of the arguments. The fix that replaced "%.*s" with "%s"
caused the trace output (when the kernel reads the event) to write
"(efault)" as it would now read the length of the string as "%s".
As the string provided is always nul terminated, there's no reason for the
internal code to use "%.*s" anyway. Just remove the length argument to
match the "%s" that is now in the format.
- Fix the ftrace subops hash logic of the manager ops hash
The function_graph uses the ftrace subops code. The subops code is a way
to have a single ftrace_ops registered with ftrace to determine what
functions will call the ftrace_ops callback. More than one user of
function graph can register a ftrace_ops with it. The function graph
infrastructure will then add this ftrace_ops as a subops with the main
ftrace_ops it registers with ftrace. This is because the functions will
always call the function graph callback which in turn calls the subops
ftrace_ops callbacks.
The main ftrace_ops must add a callback to all the functions that the
subops want a callback from. When a subops is registered, it will update
the main ftrace_ops hash to include the functions it wants. This is the
logic that was broken.
The ftrace_ops hash has a "filter_hash" and a "notrace_hash" were all the
functions in the filter_hash but not in the notrace_hash are attached by
ftrace. The original logic would have the main ftrace_ops filter_hash be a
union of all the subops filter_hashes and the main notrace_hash would be a
intersect of all the subops filter hashes. But this was incorrect because
the notrace hash depends on the filter_hash it is associated to and not
the union of all filter_hashes.
Instead, when a subops is added, just include all the functions of the
subops hash that are in its filter_hash but not in its notrace_hash. The
main subops hash should not use its notrace hash, unless all of its subops
hashes have an empty filter_hash (which means to attach to all functions),
and then, and only then, the main ftrace_ops notrace hash can be the
intersect of all the subops hashes.
This not only fixes the bug, but also simplifies the code.
- Add a selftest to better test the subops filtering
Add a selftest that would catch the bug fixed by the above change.
- Fix extra newline printed in function tracing with retval
The function parameter code changed the output logic slightly and called
print_graph_retval() and also printed a newline. The print_graph_retval()
also prints a newline which caused blank lines to be printed in the
function graph tracer when retval was added. This caused one of the
selftests to fail if retvals were enabled. Instead remove the new line
output from print_graph_retval() and have the callers always print the
new line so that it doesn't have to do special logic if it calls
print_graph_retval() or not.
- Fix out-of-bound memory access in the runtime verifier
When rv_is_container_monitor() is called on the last entry on the link
list it references the next entry, which is the list head and causes an
out-of-bound memory access.
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Merge tag 'trace-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Hide get_vm_area() from MMUless builds
The function get_vm_area() is not defined when CONFIG_MMU is not
defined. Hide that function within #ifdef CONFIG_MMU.
- Fix output of synthetic events when they have dynamic strings
The print fmt of the synthetic event's format file use to have "%.*s"
for dynamic size strings even though the user space exported
arguments had only __get_str() macro that provided just a nul
terminated string. This was fixed so that user space could parse this
properly.
But the reason that it had "%.*s" was because internally it provided
the maximum size of the string as one of the arguments. The fix that
replaced "%.*s" with "%s" caused the trace output (when the kernel
reads the event) to write "(efault)" as it would now read the length
of the string as "%s".
As the string provided is always nul terminated, there's no reason
for the internal code to use "%.*s" anyway. Just remove the length
argument to match the "%s" that is now in the format.
- Fix the ftrace subops hash logic of the manager ops hash
The function_graph uses the ftrace subops code. The subops code is a
way to have a single ftrace_ops registered with ftrace to determine
what functions will call the ftrace_ops callback. More than one user
of function graph can register a ftrace_ops with it. The function
graph infrastructure will then add this ftrace_ops as a subops with
the main ftrace_ops it registers with ftrace. This is because the
functions will always call the function graph callback which in turn
calls the subops ftrace_ops callbacks.
The main ftrace_ops must add a callback to all the functions that the
subops want a callback from. When a subops is registered, it will
update the main ftrace_ops hash to include the functions it wants.
This is the logic that was broken.
The ftrace_ops hash has a "filter_hash" and a "notrace_hash" where
all the functions in the filter_hash but not in the notrace_hash are
attached by ftrace. The original logic would have the main ftrace_ops
filter_hash be a union of all the subops filter_hashes and the main
notrace_hash would be a intersect of all the subops filter hashes.
But this was incorrect because the notrace hash depends on the
filter_hash it is associated to and not the union of all
filter_hashes.
Instead, when a subops is added, just include all the functions of
the subops hash that are in its filter_hash but not in its
notrace_hash. The main subops hash should not use its notrace hash,
unless all of its subops hashes have an empty filter_hash (which
means to attach to all functions), and then, and only then, the main
ftrace_ops notrace hash can be the intersect of all the subops
hashes.
This not only fixes the bug, but also simplifies the code.
- Add a selftest to better test the subops filtering
Add a selftest that would catch the bug fixed by the above change.
- Fix extra newline printed in function tracing with retval
The function parameter code changed the output logic slightly and
called print_graph_retval() and also printed a newline. The
print_graph_retval() also prints a newline which caused blank lines
to be printed in the function graph tracer when retval was added.
This caused one of the selftests to fail if retvals were enabled.
Instead remove the new line output from print_graph_retval() and have
the callers always print the new line so that it doesn't have to do
special logic if it calls print_graph_retval() or not.
- Fix out-of-bound memory access in the runtime verifier
When rv_is_container_monitor() is called on the last entry on the
link list it references the next entry, which is the list head and
causes an out-of-bound memory access.
* tag 'trace-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
rv: Fix out-of-bound memory access in rv_is_container_monitor()
ftrace: Do not have print_graph_retval() add a newline
tracing/selftest: Add test to better test subops filtering of function graph
ftrace: Fix accounting of subop hashes
ftrace: Properly merge notrace hashes
tracing: Do not add length to print format in synthetic events
tracing: Hide get_vm_area() from MMUless builds
7cdabafc00