commit f1d3cbfaafc10464550c6d3a125f4fc802bbaed5 upstream.
The functions:
fetch_store_strlen_user()
fetch_store_strlen()
fetch_store_string_user()
fetch_store_string()
are identical in both trace_kprobe.c and trace_eprobe.c. Move them into
a new header file trace_probe_kernel.h to share it. This code will later
be used by the synthetic events as well.
Marked for stable as a fix for a crash in synthetic events requires it.
Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Fixes: bd82631d7c ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f04dec93466a0481763f3b56cdadf8076e28bfbf upstream.
Currently when an event probe (eprobe) hooks to a string field, it does
not display it as a string, but instead as a number. This makes the field
rather useless. Handle the different kinds of strings, dynamic, static,
relational/dynamic etc.
Now when a string field is used, the ":string" type can be used to display
it:
echo "e:sw sched/sched_switch comm=$next_comm:string" > dynamic_events
Link: https://lkml.kernel.org/r/20220820134400.959640191@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6a832ec3d680b3a4f4fad5752672827d71bae501 upstream.
Currently, if a symbol "@" is attempted to be used with an event probe
(eprobes), it will cause a NULL pointer dereference crash.
Both kprobes and uprobes can reference data other than the main registers.
Such as immediate address, symbols and the current task name. Have eprobes
do the same thing.
For "comm", if "comm" is used and the event being attached to does not
have the "comm" field, then make it the "$comm" that kprobes has. This is
consistent to the way histograms and filters work.
Link: https://lkml.kernel.org/r/20220820134401.136924220@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the syscall trace points are not configured in, the kselftests for
ftrace will try to attach an event probe (eprobe) to one of the system
call trace points. This triggered a WARNING, because the failure only
expects to see memory issues. But this is not the only failure. The user
may attempt to attach to a non existent event, and the kernel must not
warn about it.
Link: https://lkml.kernel.org/r/20211027120854.0680aa0f@gandalf.local.home
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When an event probe is to be removed via the API that created it via the
dynamic events, an -ENOENT error is returned.
This is because the removal of the event probe does not expect to see the
event system and name that the event probe is attached to, even though
that's part of the API to create it. As the removal of probes is to use
the same API as they are created.
In fact, the removal is not consistent with the kprobes and uprobes
removal. Fix that by allowing various ways to remove the eprobe.
The eprobe is created with:
e:[GROUP/]NAME SYSTEM/EVENT [OPTIONS]
Have it get removed by echoing in the following into dynamic_events:
# Remove all eprobes with NAME
echo '-:NAME' >> dynamic_events
# Remove a specific eprobe
echo '-:GROUP/NAME' >> dynamic_events
echo '-:GROUP/NAME SYSTEM/EVENT' >> dynamic_events
echo '-:NAME SYSTEM/EVENT' >> dynamic_events
echo '-:GROUP/NAME SYSTEM/EVENT OPTIONS' >> dynamic_events
echo '-:NAME SYSTEM/EVENT OPTIONS' >> dynamic_events
Link: https://lkml.kernel.org/r/20211012081925.0e19cc4f@gandalf.local.home
Link: https://lkml.kernel.org/r/20211013205533.630722129@goodmis.org
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
There are two bugs in this code. First, if the kzalloc() fails it leads
to a NULL dereference of "ep" on the next line. Second, if the
alloc_event_probe() function returns an error then it leads to an
error pointer dereference in the caller.
Link: https://lkml.kernel.org/r/20210824115150.GI31143@kili
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
A new dynamic event is introduced: event probe. The event is attached
to an existing tracepoint and uses its fields as arguments. The user
can specify custom format string of the new event, select what tracepoint
arguments will be printed and how to print them.
An event probe is created by writing configuration string in
'dynamic_events' ftrace file:
e[:[SNAME/]ENAME] SYSTEM/EVENT [FETCHARGS] - Set an event probe
-:SNAME/ENAME - Delete an event probe
Where:
SNAME - System name, if omitted 'eprobes' is used.
ENAME - Name of the new event in SNAME, if omitted the SYSTEM_EVENT is used.
SYSTEM - Name of the system, where the tracepoint is defined, mandatory.
EVENT - Name of the tracepoint event in SYSTEM, mandatory.
FETCHARGS - Arguments:
<name>=$<field>[:TYPE] - Fetch given filed of the tracepoint and print
it as given TYPE with given name. Supported
types are:
(u8/u16/u32/u64/s8/s16/s32/s64), basic type
(x8/x16/x32/x64), hexadecimal types
"string", "ustring" and bitfield.
Example, attach an event probe on openat system call and print name of the
file that will be opened:
echo "e:esys/eopen syscalls/sys_enter_openat file=\$filename:string" >> dynamic_events
A new dynamic event is created in events/esys/eopen/ directory. It
can be deleted with:
echo "-:esys/eopen" >> dynamic_events
Filters, triggers and histograms can be attached to the new event, it can
be matched in synthetic events. There is one limitation - an event probe
can not be attached to kprobe, uprobe or another event probe.
Link: https://lkml.kernel.org/r/20210812145805.2292326-1-tz.stoyanov@gmail.com
Link: https://lkml.kernel.org/r/20210819152825.142428383@goodmis.org
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Co-developed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
