The patch titled
kill_pid_info: don't take now unneeded tasklist_lock
has been removed from the -mm tree. Its filename was
kill_pid_info-dont-take-now-unneeded-tasklist_lock.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: kill_pid_info: don't take now unneeded tasklist_lock
From: Oleg Nesterov <oleg@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/signal.h | 2 --
kernel/signal.c | 7 +------
2 files changed, 1 insertion(+), 8 deletions(-)
diff -puN include/linux/signal.h~kill_pid_info-dont-take-now-unneeded-tasklist_lock include/linux/signal.h
--- a/include/linux/signal.h~kill_pid_info-dont-take-now-unneeded-tasklist_lock
+++ a/include/linux/signal.h
@@ -362,8 +362,6 @@ int unhandled_signal(struct task_struct
#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))
diff -puN kernel/signal.c~kill_pid_info-dont-take-now-unneeded-tasklist_lock kernel/signal.c
--- a/kernel/signal.c~kill_pid_info-dont-take-now-unneeded-tasklist_lock
+++ a/kernel/signal.c
@@ -1039,9 +1039,6 @@ int kill_pid_info(int sig, struct siginf
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;
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
posix-timers-bug-10460-discard-the-pending-signal-when-the-timer-is-destroyed.patch
workqueue-remove-redundant-function-invocation.patch
put_pid-make-sure-we-dont-free-the-live-pid.patch
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