Searched hist:e8e1abe92fd7ea9d823a3aaf81d10e2cba593b6b (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/kernel/ |
| H A D | fork.c | diff e8e1abe92fd7ea9d823a3aaf81d10e2cba593b6b Wed Dec 03 10:04:51 CST 2008 Steven Rostedt <srostedt@redhat.com> ftrace: fix race in function graph during fork
Impact: graph tracer race/crash fix
There is a nasy race in startup of a new process running the
function graph tracer. In fork.c:
total_forks++;
spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
ftrace_graph_init_task(p);
proc_fork_connector(p);
cgroup_post_fork(p);
return p;
The new task is free to run as soon as the tasklist_lock is released.
This is before the ftrace_graph_init_task. If the task does run
it will be using the same ret_stack and curr_ret_stack as the parent.
This will cause crashes that are difficult to debug.
This patch moves the ftrace_graph_init_task to just after the alloc_pid
code. This fixes the above race.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|