linux-toradex.git/kernel/trace/trace_uprobe.c, branch v5.16

tracing/uprobe: Fix uprobe_perf_open probes iteration

2021-11-24T01:52:01+00:00

Add missing 'tu' variable initialization in the probes loop,
otherwise the head 'tu' is used instead of added probes.

Link: https://lkml.kernel.org/r/20211123142801.182530-1-jolsa@kernel.org

Cc: stable@vger.kernel.org
Fixes: 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
Acked-by: Masami Hiramatsu 
Signed-off-by: Jiri Olsa 
Signed-off-by: Steven Rostedt (VMware)

tracing: Disable "other" permission bits in the tracefs files

2021-10-08T22:08:43+00:00

When building the files in the tracefs file system, do not by default set
any permissions for OTH (other). This will make it easier for admins who
want to define a group for accessing tracefs and not having to first
disable all the permission bits for "other" in the file system.

As tracing can leak sensitive information, it should never by default
allowing all users access. An admin can still set the permission bits for
others to have access, which may be useful for creating a honeypot and
seeing who takes advantage of it and roots the machine.

Link: https://lkml.kernel.org/r/20210818153038.864149276@goodmis.org

Signed-off-by: Steven Rostedt (VMware)

tracing/probes: Reject events which have the same name of existing one

2021-08-19T13:15:19+00:00

Since kprobe_events and uprobe_events only check whether the
other same-type probe event has the same name or not, if the
user gives the same name of the existing tracepoint event (or
the other type of probe events), it silently fails to create
the tracefs entry (but registered.) as below.

/sys/kernel/tracing # ls events/task/task_rename
enable   filter   format   hist     id       trigger
/sys/kernel/tracing # echo p:task/task_rename vfs_read >> kprobe_events
[  113.048508] Could not create tracefs 'task_rename' directory
/sys/kernel/tracing # cat kprobe_events
p:task/task_rename vfs_read

To fix this issue, check whether the existing events have the
same name or not in trace_probe_register_event_call(). If exists,
it rejects to register the new event.

Link: https://lkml.kernel.org/r/162936876189.187130.17558311387542061930.stgit@devnote2

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

tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs

2021-08-19T13:09:03+00:00

In preparation to allow event probes to use the process_fetch_insn()
callback in trace_probe_tmpl.h, change the data passed to it from a
pointer to pt_regs, as the event probe will not be using regs, and make it
a void pointer instead.

Update the process_fetch_insn() callers for kprobe and uprobe events to
have the regs defined in the function and just typecast the void pointer
parameter.

Link: https://lkml.kernel.org/r/20210819041842.291622924@goodmis.org

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

tracing/probe: Change traceprobe_set_print_fmt() to take a type

2021-08-19T13:08:29+00:00

Instead of a boolean "is_return" have traceprobe_set_print_fmt() take a
type (currently just PROBE_PRINT_NORMAL and PROBE_PRINT_RETURN). This will
simplify adding different types. For example, the development of the
event_probe, will need its own type as it prints an event, and not an IP.

Link: https://lkml.kernel.org/r/20210819041842.104626301@goodmis.org

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

tracing/probes: Use struct_size() instead of defining custom macros

2021-08-18T22:13:52+00:00

Remove SIZEOF_TRACE_KPROBE() and SIZEOF_TRACE_UPROBE() and use
struct_size() as that's what it is made for. No need to have custom
macros. Especially since struct_size() has some extra memory checks for
correctness.

Link: https://lkml.kernel.org/r/20210817035027.795000217@goodmis.org

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

tracing/probe: Have traceprobe_parse_probe_arg() take a const arg

2021-08-18T22:13:52+00:00

The two places that call traceprobe_parse_probe_arg() allocate a temporary
buffer to copy the argv[i] into, because argv[i] is constant and the
traceprobe_parse_probe_arg() will modify it to do the parsing. These two
places allocate this buffer and then free it right after calling this
function, leaving the onus of this allocation to the caller.

As there's about to be a third user of this function that will have to do
the same thing, instead of having the caller allocate the temporary
buffer, simply move that allocation into the traceprobe_parse_probe_arg()
itself, which will simplify the code of the callers.

Link: https://lkml.kernel.org/r/20210817035027.385422828@goodmis.org

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

tracing: Have dynamic events have a ref counter

2021-08-18T22:13:47+00:00

As dynamic events are not created by modules, if something is attached to
one, calling "try_module_get()" on its "mod" field, is not going to keep
the dynamic event from going away.

Since dynamic events do not need the "mod" pointer of the event structure,
make a union out of it in order to save memory (there's one structure for
each of the thousand+ events in the kernel), and have any event with the
DYNAMIC flag set to use a ref counter instead.

Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/
Link: https://lkml.kernel.org/r/20210817035027.174869074@goodmis.org

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

tracing: Add DYNAMIC flag for dynamic events

2021-08-18T22:10:32+00:00

To differentiate between static and dynamic events, add a new flag
DYNAMIC to the event flags that all dynamic events have set. This will
allow to differentiate when attaching to a dynamic event from a static
event.

Static events have a mod pointer that references the module they were
created in (or NULL for core kernel). This can be incremented when the
event has something attached to it. But there exists no such mechanism for
dynamic events. This is dangerous as the dynamic events may now disappear
without the "attachment" knowing that it no longer exists.

To enforce the dynamic flag, change dyn_event_add() to pass the event that
is being created such that it can set the DYNAMIC flag of the event. This
helps make sure that no location that creates a dynamic event misses
setting this flag.

Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/
Link: https://lkml.kernel.org/r/20210817035026.936958254@goodmis.org

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

tracing/dynevent: Delegate parsing to create function

2021-02-09T17:52:15+00:00

Delegate command parsing to each create function so that the
command syntax can be customized.

This requires changes to the kprobe/uprobe/synthetic event handling,
which are also included here.

Link: https://lkml.kernel.org/r/e488726f49cbdbc01568618f8680584306c4c79f.1612208610.git.zanussi@kernel.org

Signed-off-by: Masami Hiramatsu 
[ zanussi@kernel.org: added synthetic event modifications ]
Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)