From 74bf4076f2ed79b5510440b72a561823a8852ec0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 25 Jan 2010 15:11:53 -0500 Subject: [PATCH] tracing: Prevent kernel oops with corrupted buffer If the contents of the ftrace ring buffer gets corrupted and the trace file is read, it could create a kernel oops (usualy just killing the user task thread). This is caused by the checking of the pid in the buffer. If the pid is negative, it still references the cmdline cache array, which could point to an invalid address. The simple fix is to test for negative PIDs. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0df1b0f2cb9e..eac6875cb990 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -951,6 +951,11 @@ void trace_find_cmdline(int pid, char comm[]) return; } + if (WARN_ON_ONCE(pid < 0)) { + strcpy(comm, ""); + return; + } + if (pid > PID_MAX_DEFAULT) { strcpy(comm, "<...>"); return; -- 2.11.4.GIT