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authorSteven Rostedt <srostedt@redhat.com>2008-11-14 16:21:19 -0800
committerIngo Molnar <mingo@elte.hu>2008-11-16 07:30:07 +0100
commitb17e8a37a13d0e87165054714434534bb7e69f2d (patch)
tree0acfd6ec460bfab35807eb6be058d946c380353e /kernel/trace
parentf3c7ac40a99f4044b843e6e2c4f46ab2d354c563 (diff)
ftrace: disable ftrace on anomalies in trace start and stop
Impact: robust feature to disable ftrace on start or stop tracing on error Currently only the initial conversion to nops will disable ftrace on an anomaly. But if an anomaly happens on start or stopping of the tracer, it will silently fail. This patch adds a check there too, to disable ftrace and warn if the conversion fails. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ftrace.c81
1 files changed, 44 insertions, 37 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3160254f6c7e..d5bd21f39524 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -348,6 +348,47 @@ ftrace_record_ip(unsigned long ip)
return rec;
}
+static void print_ip_ins(const char *fmt, unsigned char *p)
+{
+ int i;
+
+ printk(KERN_CONT "%s", fmt);
+
+ for (i = 0; i < MCOUNT_INSN_SIZE; i++)
+ printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
+}
+
+static void ftrace_bug(int failed, unsigned long ip,
+ unsigned char *expected,
+ unsigned char *replace)
+{
+ switch (failed) {
+ case -EFAULT:
+ FTRACE_WARN_ON_ONCE(1);
+ pr_info("ftrace faulted on modifying ");
+ print_ip_sym(ip);
+ break;
+ case -EINVAL:
+ FTRACE_WARN_ON_ONCE(1);
+ pr_info("ftrace failed to modify ");
+ print_ip_sym(ip);
+ print_ip_ins(" expected: ", expected);
+ print_ip_ins(" actual: ", (unsigned char *)ip);
+ print_ip_ins(" replace: ", replace);
+ printk(KERN_CONT "\n");
+ break;
+ case -EPERM:
+ FTRACE_WARN_ON_ONCE(1);
+ pr_info("ftrace faulted on writing ");
+ print_ip_sym(ip);
+ break;
+ default:
+ FTRACE_WARN_ON_ONCE(1);
+ pr_info("ftrace faulted on unknown error ");
+ print_ip_sym(ip);
+ }
+}
+
#define FTRACE_ADDR ((long)(ftrace_caller))
static int
@@ -465,22 +506,13 @@ static void ftrace_replace_code(int enable)
if ((system_state == SYSTEM_BOOTING) ||
!core_kernel_text(rec->ip)) {
ftrace_free_rec(rec);
- }
+ } else
+ ftrace_bug(failed, rec->ip, old, new);
}
}
}
}
-static void print_ip_ins(const char *fmt, unsigned char *p)
-{
- int i;
-
- printk(KERN_CONT "%s", fmt);
-
- for (i = 0; i < MCOUNT_INSN_SIZE; i++)
- printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
-}
-
static int
ftrace_code_disable(struct dyn_ftrace *rec)
{
@@ -495,32 +527,7 @@ ftrace_code_disable(struct dyn_ftrace *rec)
ret = ftrace_modify_code(ip, call, nop);
if (ret) {
- switch (ret) {
- case -EFAULT:
- FTRACE_WARN_ON_ONCE(1);
- pr_info("ftrace faulted on modifying ");
- print_ip_sym(ip);
- break;
- case -EINVAL:
- FTRACE_WARN_ON_ONCE(1);
- pr_info("ftrace failed to modify ");
- print_ip_sym(ip);
- print_ip_ins(" expected: ", call);
- print_ip_ins(" actual: ", (unsigned char *)ip);
- print_ip_ins(" replace: ", nop);
- printk(KERN_CONT "\n");
- break;
- case -EPERM:
- FTRACE_WARN_ON_ONCE(1);
- pr_info("ftrace faulted on writing ");
- print_ip_sym(ip);
- break;
- default:
- FTRACE_WARN_ON_ONCE(1);
- pr_info("ftrace faulted on unknown error ");
- print_ip_sym(ip);
- }
-
+ ftrace_bug(ret, ip, call, nop);
rec->flags |= FTRACE_FL_FAILED;
return 0;
}