Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-11 14:42:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

ftrace: disable tracing on resize

Browse Source 
Impact: fix for bug on resize

This patch addresses the bug found here:

 http://bugzilla.kernel.org/show_bug.cgi?id=11996

When ftrace converted to the new unified trace buffer, the resizing of
the buffer was not protected as much as it was originally. If tracing
is performed while the resize occurs, then the buffer can be corrupted.

This patch disables all ftrace buffer modifications before a resize
takes place.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This commit is contained in:
Steven Rostedt 2008-11-10 21:46:00 -05:00
parent 3ad4f59705
commit bf5e6519b8
1 changed files with 16 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
kernel/trace/trace.c
View File

@ -2676,7 +2676,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
{
unsigned long val;
char buf[64];
int ret;
int ret, cpu;
struct trace_array *tr = filp->private_data;
if (cnt >= sizeof(buf))
@ -2704,6 +2704,14 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
goto out;
}
/* disable all cpu buffers */
for_each_tracing_cpu(cpu) {
if (global_trace.data[cpu])
atomic_inc(&global_trace.data[cpu]->disabled);
if (max_tr.data[cpu])
atomic_inc(&max_tr.data[cpu]->disabled);
}
if (val != global_trace.entries) {
ret = ring_buffer_resize(global_trace.buffer, val);
if (ret < 0) {
@ -2735,6 +2743,13 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
if (tracing_disabled)
cnt = -ENOMEM;
out:
for_each_tracing_cpu(cpu) {
if (global_trace.data[cpu])
atomic_dec(&global_trace.data[cpu]->disabled);
if (max_tr.data[cpu])
atomic_dec(&max_tr.data[cpu]->disabled);
}
max_tr.entries = global_trace.entries;
mutex_unlock(&trace_types_lock);