shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-06 02:50:49 +09:00
Code Issues Packages Projects Releases Wiki Activity

tracing: Allocate the snapshot buffer before enabling probe

Browse Source 
commit df62db5be2 upstream.

Currently the snapshot trigger enables the probe and then allocates the
snapshot. If the probe triggers before the allocation, it could cause the
snapshot to fail and turn tracing off. It's best to allocate the snapshot
buffer first, and then enable the trigger. If something goes wrong in the
enabling of the trigger, the snapshot buffer is still allocated, but it can
also be freed by the user by writting zero into the snapshot buffer file.

Also add a check of the return status of alloc_snapshot().

Fixes: 77fd5c15e3 ("tracing: Add snapshot trigger to function probes")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Steven Rostedt (VMware)
2017-04-19 12:07:08 -04:00
committed by Greg Kroah-Hartman
parent 174a74dbca
commit d4decac1ed
1 changed files with 5 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
kernel/trace/trace.c
View File

@@ -6481,11 +6481,13 @@ ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
return ret;
out_reg:
ret = alloc_snapshot(&global_trace);
if (ret < 0)
goto out;
ret = register_ftrace_function_probe(glob, ops, count);
if (ret >= 0)
alloc_snapshot(&global_trace);
out:
return ret < 0 ? ret : 0;
}