linux.git/kernel/trace/trace_boot.c, branch v6.18.21

tracing: Allow creating instances with specified system events

2023-12-19T04:14:16+00:00

A trace instance may only need to enable specific events. As the eventfs
directory of an instance currently creates all events which adds overhead,
allow internal instances to be created with just the events in systems
that they care about. This currently only deals with systems and not
individual events, but this should bring down the overhead of creating
instances for specific use cases quite bit.

The trace_array_get_by_name() now has another parameter "systems". This
parameter is a const string pointer of a comma/space separated list of
event systems that should be created by the trace_array. (Note if the
trace_array already exists, this parameter is ignored).

The list of systems is saved and if a module is loaded, its events will
not be added unless the system for those events also match the systems
string.

Link: https://lore.kernel.org/linux-trace-kernel/20231213093701.03fddec0@gandalf.local.home

Cc: Masami Hiramatsu 
Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Cc: Sean Paul 
Cc: Arun Easi   
Cc: Daniel Wagner 
Tested-by: Dmytro Maluka 
Signed-off-by: Steven Rostedt (Google)

tracing/boot: Test strscpy() against less than zero for error

2023-07-05T14:30:49+00:00

Instead of checking for -E2BIG, it is better to just check for less than
zero of strscpy() for error. Testing for -E2BIG is not very robust, and
the calling code does not really care about the error code, just that
there was an error.

One of the updates to convert strlcpy() to strscpy() had a v2 version
that changed the test from testing against -E2BIG to less than zero, but I
took the v1 version that still tested for -E2BIG.

Link: https://lore.kernel.org/linux-trace-kernel/20230615180420.400769-1-azeemshaikh38@gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230704100807.707d1605@rorschach.local.home

Cc: Mark Rutland 
Cc: Azeem Shaikh 
Cc: Kees Cook 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

tracing/boot: Replace strlcpy with strscpy

2023-06-22T14:39:56+00:00

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().

Direct replacement is safe here since return value of -E2BIG
is used to check for truncation instead of sizeof(dest).

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Link: https://lore.kernel.org/linux-trace-kernel/20230613004125.3539934-1-azeemshaikh38@gmail.com

Cc: Masami Hiramatsu 
Signed-off-by: Azeem Shaikh 
Reviewed-by: Kees Cook 
Signed-off-by: Steven Rostedt (Google)

tracing: Initialize integer variable to prevent garbage return value

2022-05-27T01:13:00+00:00

Initialize the integer variable to 0 to fix the clang scan warning:
Undefined or garbage value returned to caller
[core.uninitialized.UndefReturn]
        return ret;

Link: https://lkml.kernel.org/r/20220522061826.1751-1-gautammenghani201@gmail.com

Cc: stable@vger.kernel.org
Fixes: 8993665abcce ("tracing/boot: Support multiple handlers for per-event histogram")
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Gautam Menghani 
Signed-off-by: Steven Rostedt (Google)

tracing: Fix missing trace_boot_init_histograms kstrdup NULL checks

2021-10-26T13:18:10+00:00

trace_boot_init_histograms misses NULL pointer checks for kstrdup
failure.

Link: https://lkml.kernel.org/r/20211015195550.22742-1-mathieu.desnoyers@efficios.com

Fixes: 64dc7f6958ef5 ("tracing/boot: Show correct histogram error command")
Acked-by: Masami Hiramatsu 
Signed-off-by: Mathieu Desnoyers 
Signed-off-by: Steven Rostedt (VMware)

bootconfig: Rename xbc_node_find_child() to xbc_node_find_subkey()

2021-09-09T23:14:33+00:00

Rename xbc_node_find_child() to xbc_node_find_subkey() for
clarifying that function returns a key node (no value node).
Since there are xbc_node_for_each_child() (loop on all child
nodes) and xbc_node_for_each_subkey() (loop on only subkey
nodes), this name distinction is necessary to avoid confusing
users.

Link: https://lkml.kernel.org/r/163119459826.161018.11200274779483115300.stgit@devnote2

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/boot: Fix to check the histogram control param is a leaf node

2021-09-09T23:14:33+00:00

Since xbc_node_find_child() doesn't ensure the returned node
is a leaf node (key-value pair or do not have subkeys),
use xbc_node_find_value to ensure the histogram control
parameter is a leaf node in trace_boot_compose_hist_cmd().

Link: https://lkml.kernel.org/r/163119459059.161018.18341288218424528962.stgit@devnote2

Fixes: e66ed86ca6c5 ("tracing/boot: Add per-event histogram action options")
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/boot: Fix trace_boot_hist_add_array() to check array is value

2021-09-09T23:14:33+00:00

trace_boot_hist_add_array() uses the combination of
xbc_node_find_child() and xbc_node_get_child() to get the
child node of the key node. But since it missed to check
the child node is data node or not, user can pass the
subkey node for the array node (anode).
To avoid this issue, check the array node is a data node.
Actually, there is xbc_node_find_value(node, key, vnode),
which ensures the @vnode is a value node, so use it in
trace_boot_hist_add_array() to fix this issue.

Link: https://lkml.kernel.org/r/163119458308.161018.1516455973625940212.stgit@devnote2

Fixes: e66ed86ca6c5 ("tracing/boot: Add per-event histogram action options")
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/boot: Fix to loop on only subkeys

2021-09-08T19:44:32+00:00

Since the commit e5efaeb8a8f5 ("bootconfig: Support mixing
a value and subkeys under a key") allows to co-exist a value
node and key nodes under a node, xbc_node_for_each_child()
is not only returning key node but also a value node.
In the boot-time tracing using xbc_node_for_each_child() to
iterate the events, groups and instances, but those must be
key nodes. Thus it must use xbc_node_for_each_subkey().

Link: https://lkml.kernel.org/r/163112988361.74896.2267026262061819145.stgit@devnote2

Fixes: e5efaeb8a8f5 ("bootconfig: Support mixing a value and subkeys under a key")
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/boot: Show correct histogram error command

2021-08-16T15:37:21+00:00

Since trigger_process_regex() modifies given trigger actions
while parsing, the error message couldn't show what command
was passed to the trigger_process_regex() when it returns
an error.

To fix that, show the backed up trigger action command
instead of parsed buffer.

Link: https://lkml.kernel.org/r/162856126413.203126.9465564928450701424.stgit@devnote2

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)