Commit c0c0b649 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

ptrace_check_attach: remove unneeded ->signal != NULL check

It is not possible to see the PT_PTRACED task without ->signal/sighand under
tasklist_lock, release_task() does ptrace_unlink() first.  If the task was
already released before, ptrace_attach() can't succeed and set PT_PTRACED.
Remove this check.
Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Acked-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 34a1738f
......@@ -99,9 +99,12 @@ int ptrace_check_attach(struct task_struct *child, int kill)
* be changed by us so it's not changing right after this.
*/
read_lock(&tasklist_lock);
if ((child->ptrace & PT_PTRACED) && child->parent == current &&
child->signal != NULL) {
if ((child->ptrace & PT_PTRACED) && child->parent == current) {
ret = 0;
/*
* child->sighand can't be NULL, release_task()
* does ptrace_unlink() before __exit_signal().
*/
spin_lock_irq(&child->sighand->siglock);
if (task_is_stopped(child))
child->state = TASK_TRACED;
......
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