Commit 8aa8a7c8 authored by Stephane Eranian's avatar Stephane Eranian Committed by Ingo Molnar

perf record: Fix buffer overrun bug in tracepoint_id_to_path()

This patch fixes a buffer overrun bug in
tracepoint_id_to_path(). The bug manisfested itself as a memory
error reported by perf record. I ran into it with perf sched:

 $ perf sched rec noploop 2 noploop for 2 seconds
 [ perf record: Woken up 14 times to write data ]
 [ perf record: Captured and wrote 42.701 MB (~1865622 samples) ]
 Fatal: No memory to alloc tracepoints list

It turned out that tracepoint_id_to_path() was reading the
tracepoint id using read() but the buffer was not large enough
to include the \n terminator for id with 4 digits or more.

The patch fixes the problem by extending the buffer to a more
reasonable size covering all possible id length include \n
terminator. Note that atoll() stops at the first non digit
character, thus it is not necessary to clear the buffer between
each read.
Signed-off-by: default avatarStephane Eranian <>
Acked-by: default avatarArnaldo Carvalho de Melo <>
Acked-by: default avatarPeter Zijlstra <>
Link: default avatarIngo Molnar <>
parent 87e24f4b
......@@ -165,7 +165,7 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
struct tracepoint_path *path = NULL;
DIR *sys_dir, *evt_dir;
struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
char id_buf[4];
char id_buf[24];
int fd;
u64 id;
char evt_path[MAXPATHLEN];
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment