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ftrace: return error on failed modified text.

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Have the ftrace_modify_code return error values:

  -EFAULT on error of reading the address

  -EINVAL if what is read does not match what it expected

  -EPERM  if the write fails to update after a successful match.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt
2008-10-23 09:32:59 -04:00
committed by Ingo Molnar
parent 34698bcbdf
commit 593eb8a2d6
3 changed files with 44 additions and 15 deletions
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21
kernel/trace/ftrace.c
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@@ -596,22 +596,22 @@ ftrace_code_disable(struct dyn_ftrace *rec)
{
unsigned long ip;
unsigned char *nop, *call;
int failed;
int ret;
ip = rec->ip;
nop = ftrace_nop_replace();
call = ftrace_call_replace(ip, mcount_addr);
failed = ftrace_modify_code(ip, call, nop);
if (failed) {
switch (failed) {
case 1:
ret = ftrace_modify_code(ip, call, nop);
if (ret) {
switch (ret) {
case -EFAULT:
WARN_ON_ONCE(1);
pr_info("ftrace faulted on modifying ");
print_ip_sym(ip);
break;
case 2:
case -EINVAL:
WARN_ON_ONCE(1);
pr_info("ftrace failed to modify ");
print_ip_sym(ip);
@@ -620,6 +620,15 @@ ftrace_code_disable(struct dyn_ftrace *rec)
print_ip_ins(" replace: ", nop);
printk(KERN_CONT "\n");
break;
case -EPERM:
WARN_ON_ONCE(1);
pr_info("ftrace faulted on writing ");
print_ip_sym(ip);
break;
default:
WARN_ON_ONCE(1);
pr_info("ftrace faulted on unknown error ");
print_ip_sym(ip);
}
rec->flags |= FTRACE_FL_FAILED;