path: root/kernel/trace/trace_stack.c
diff options
authorNamhyung Kim <>2013-06-07 17:01:16 +0800
committerGreg Kroah-Hartman <>2013-06-13 09:45:03 -0700
commit3a22cc7f184b77731816e55662cd12f0c3d24d56 (patch)
treece3612a4ea2ec1ed53d5c98a24b88aa80067129c /kernel/trace/trace_stack.c
parentce840e2f7825bfd240782dc209c2f2b8db514287 (diff)
tracing: Fix possible NULL pointer dereferences
commit 6a76f8c0ab19f215af2a3442870eeb5f0e81998d upstream. Currently set_ftrace_pid and set_graph_function files use seq_lseek for their fops. However seq_open() is called only for FMODE_READ in the fops->open() so that if an user tries to seek one of those file when she open it for writing, it sees NULL seq_file and then panic. It can be easily reproduced with following command: $ cd /sys/kernel/debug/tracing $ echo 1234 | sudo tee -a set_ftrace_pid In this example, GNU coreutils' tee opens the file with fopen(, "a") and then the fopen() internally calls lseek(). Link: Signed-off-by: Namhyung Kim <> Cc: Frederic Weisbecker <> Cc: Ingo Molnar <> Cc: Namhyung Kim <> Signed-off-by: Steven Rostedt <> [ lizf: adjust context ] Signed-off-by: Li Zefan <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'kernel/trace/trace_stack.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index c70f6bfbb732..8298997c2486 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -384,7 +384,7 @@ static const struct file_operations stack_trace_filter_fops = {
.open = stack_trace_filter_open,
.read = seq_read,
.write = ftrace_filter_write,
- .llseek = ftrace_regex_lseek,
+ .llseek = ftrace_filter_lseek,
.release = ftrace_regex_release,