[PATCH 2/3] tracing/ksym_tracer: fix write operation of ksym_trace_filter

Xiao Guangrong
2009-07-22T03:23:48Z

This patch fix 2 bugs:
- fix the return value of ksym_trace_filter_write() when we want to
clear symbol in ksym_trace_filter file
for example:
# echo global_trace:rw- > /debug/tracing/ksym_trace_filter
# echo global_trace:--- > /debug/tracing/ksym_trace_filter
-bash: echo: write error: Invalid argument
# cat /debug/tracing/ksym_trace_filter
#
We want to clear 'global_trace' in ksym_trace_filter, it complain
with "Invalid argument", but the operation is successful

- the "r--" access types is not allowed, but ksym_trace_filter file think
it OK
for example:
# echo ksym_tracer_mutex:r-- > ksym_trace_filter
-bash: echo: write error: Resource temporarily unavailable
# dmesg
ksym_tracer request failed. Try again later!!

The error occur at register_kernel_hw_breakpoint(), but It's should
at access types parser

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
kernel/trace/trace_ksym.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index fbf3a8e..cd5cb65 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -135,6 +135,9 @@ static int ksym_trace_get_access_type(char *str)
case 6:
access = HW_BREAKPOINT_RW;
break;
+ case 4:
+ access = -EINVAL;
+ break;
case 2:
access = HW_BREAKPOINT_WRITE;
break;
@@ -312,6 +315,7 @@ static ssize_t ksym_trace_filter_write(struct file *file,
kfree(entry->ksym_hbp->info.name);
kfree(entry->ksym_hbp);
kfree(entry);
+ ret = 0;
goto out;
} else {
/* Check for malformed request: (4) */
--
1.6.1.2