cpu-timers: Avoid iterating over all threads in fastpath_timer_check()

Spread p->sighand->siglock locking scope to make sure that
fastpath_timer_check() never iterates over all threads. Without
locking there is small possibility that signal->cputimer will stop
running while we write values to signal->cputime_expires.

Calling thread_group_cputime() from fastpath_timer_check() is not only
bad because it is slow, also it is racy with __exit_signal() which can
lead to invalid signal->{s,u}time values.

Signed-off-by: Stanislaw Gruszka <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Hidetoshi Seto <[email protected]>
Cc: Balbir Singh <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>

0 files changed, 0 insertions, 0 deletions