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authorNamhyung Kim <namhyung.kim@lge.com>2013-04-11 15:55:01 +0900
committerSteven Rostedt <rostedt@goodmis.org>2013-04-12 14:43:34 -0400
commit6a76f8c0ab19f215af2a3442870eeb5f0e81998d (patch)
tree551f1c13779323e06b8ef906192ba7a5d87aa7b6 /kernel/trace/trace_stack.c
parent83e03b3fe4daffdebbb42151d5410d730ae50bd1 (diff)
tracing: Fix possible NULL pointer dereferences
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: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: stable@vger.kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_stack.c')
-rw-r--r--kernel/trace/trace_stack.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 42ca822fc70..83a8b5b7bd3 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -322,7 +322,7 @@ 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,
};