Staging: android: task_get_unused_fd_flags: fix the wrong usage of tsk->signal

Compile tested.

task_struct->signal is not protected by RCU, the code is bogus.
Change the code to take ->siglock to pin ->signal.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Brian Swetland <swetland@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oleg Nesterov 2009-01-18 18:17:20 +01:00 committed by Greg Kroah-Hartman
parent 191805ac41
commit 1176e83aff

View file

@ -319,6 +319,7 @@ int task_get_unused_fd_flags(struct task_struct *tsk, int flags)
int fd, error;
struct fdtable *fdt;
unsigned long rlim_cur;
unsigned long irqs;
if (files == NULL)
return -ESRCH;
@ -335,12 +336,11 @@ int task_get_unused_fd_flags(struct task_struct *tsk, int flags)
* N.B. For clone tasks sharing a files structure, this test
* will limit the total number of files that can be opened.
*/
rcu_read_lock();
if (tsk->signal)
rlim_cur = 0;
if (lock_task_sighand(tsk, &irqs)) {
rlim_cur = tsk->signal->rlim[RLIMIT_NOFILE].rlim_cur;
else
rlim_cur = 0;
rcu_read_unlock();
unlock_task_sighand(tsk, &irqs);
}
if (fd >= rlim_cur)
goto out;