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kprobes: use _do_fork() in samples to make them work again
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Commit 3033f14 ("clone: support passing tls argument via C rather
than pt_regs magic") introduced _do_fork() that allowed to pass @tls
parameter.

The old do_fork() is defined only for architectures that are not ready
to use this way and do not define HAVE_COPY_THREAD_TLS.

Let's use _do_fork() in the kprobe examples to make them work again on
all architectures.

Signed-off-by: Petr Mladek <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Thiago Macieira <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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pmladek authored and torvalds committed Oct 2, 2015
1 parent 09a59a9 commit 54aea45
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Showing 3 changed files with 12 additions and 12 deletions.
14 changes: 7 additions & 7 deletions samples/kprobes/jprobe_example.c
Original file line number Diff line number Diff line change
@@ -1,13 +1,13 @@
/*
* Here's a sample kernel module showing the use of jprobes to dump
* the arguments of do_fork().
* the arguments of _do_fork().
*
* For more information on theory of operation of jprobes, see
* Documentation/kprobes.txt
*
* Build and insert the kernel module as done in the kprobe example.
* You will see the trace data in /var/log/messages and on the
* console whenever do_fork() is invoked to create a new process.
* console whenever _do_fork() is invoked to create a new process.
* (Some messages may be suppressed if syslogd is configured to
* eliminate duplicate messages.)
*/
Expand All @@ -17,13 +17,13 @@
#include <linux/kprobes.h>

/*
* Jumper probe for do_fork.
* Jumper probe for _do_fork.
* Mirror principle enables access to arguments of the probed routine
* from the probe handler.
*/

/* Proxy routine having the same arguments as actual do_fork() routine */
static long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
/* Proxy routine having the same arguments as actual _do_fork() routine */
static long j_do_fork(unsigned long clone_flags, unsigned long stack_start,
unsigned long stack_size, int __user *parent_tidptr,
int __user *child_tidptr)
{
Expand All @@ -36,9 +36,9 @@ static long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
}

static struct jprobe my_jprobe = {
.entry = jdo_fork,
.entry = j_do_fork,
.kp = {
.symbol_name = "do_fork",
.symbol_name = "_do_fork",
},
};

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6 changes: 3 additions & 3 deletions samples/kprobes/kprobe_example.c
Original file line number Diff line number Diff line change
@@ -1,13 +1,13 @@
/*
* NOTE: This example is works on x86 and powerpc.
* Here's a sample kernel module showing the use of kprobes to dump a
* stack trace and selected registers when do_fork() is called.
* stack trace and selected registers when _do_fork() is called.
*
* For more information on theory of operation of kprobes, see
* Documentation/kprobes.txt
*
* You will see the trace data in /var/log/messages and on the console
* whenever do_fork() is invoked to create a new process.
* whenever _do_fork() is invoked to create a new process.
*/

#include <linux/kernel.h>
Expand All @@ -16,7 +16,7 @@

/* For each probe you need to allocate a kprobe structure */
static struct kprobe kp = {
.symbol_name = "do_fork",
.symbol_name = "_do_fork",
};

/* kprobe pre_handler: called just before the probed instruction is executed */
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4 changes: 2 additions & 2 deletions samples/kprobes/kretprobe_example.c
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@
*
* usage: insmod kretprobe_example.ko func=<func_name>
*
* If no func_name is specified, do_fork is instrumented
* If no func_name is specified, _do_fork is instrumented
*
* For more information on theory of operation of kretprobes, see
* Documentation/kprobes.txt
Expand All @@ -25,7 +25,7 @@
#include <linux/limits.h>
#include <linux/sched.h>

static char func_name[NAME_MAX] = "do_fork";
static char func_name[NAME_MAX] = "_do_fork";
module_param_string(func, func_name, NAME_MAX, S_IRUGO);
MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the"
" function's execution time");
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