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kill_pid_info: don't take now unneeded tasklist_lock

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Previously handle_stop_signal(SIGCONT) could drop ->siglock.  That is why
kill_pid_info(SIGCONT) takes tasklist_lock to make sure the target task can't
go away after unlock.  Not needed now.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2008-04-30 00:52:45 -07:00 committed by Linus Torvalds
parent e442055193
commit 6ca25b5513
2 changed files with 1 additions and 8 deletions
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2
include/linux/signal.h
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@ -362,8 +362,6 @@ int unhandled_signal(struct task_struct *tsk, int sig);
#define sig_kernel_stop(sig) \
(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_STOP_MASK))
#define sig_needs_tasklist(sig) ((sig) == SIGCONT)
#define sig_user_defined(t, signr) \
(((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) && \
((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))

7
kernel/signal.c
View File

@ -1039,9 +1039,6 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
struct task_struct *p;
rcu_read_lock();
if (unlikely(sig_needs_tasklist(sig)))
read_lock(&tasklist_lock);
retry:
p = pid_task(pid, PIDTYPE_PID);
if (p) {
@ -1055,10 +1052,8 @@ retry:
*/
goto retry;
}
if (unlikely(sig_needs_tasklist(sig)))
read_unlock(&tasklist_lock);
rcu_read_unlock();
return error;
}