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Commit 486ccb05 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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[PATCH] elf_core_dump: don't take tasklist_lock 



do_each_thread() is rcu-safe, and all tasks which use this ->mm must sleep
in wait_for_completion(&mm->core_done) at this point, so we can use RCU
locks.

Also, remove unneeded INIT_LIST_HEAD(new) before list_add(new, head).

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b22b4cdd

fs/binfmt_elf.c

+3 −4
Original line number Original line Diff line number Diff line
@@ -1479,20 +1479,19 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file) 




	if (signr) {

	if (signr) {

		struct elf_thread_status *tmp;

		struct elf_thread_status *tmp;

		read_lock(&tasklist_lock);

		rcu_read_lock();

		do_each_thread(g,p)

		do_each_thread(g,p)

			if (current->mm == p->mm && current != p) {

			if (current->mm == p->mm && current != p) {

				tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);

				tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);

				if (!tmp) {

				if (!tmp) {

					read_unlock(&tasklist_lock);

					rcu_read_unlock();

					goto cleanup;

					goto cleanup;

				}

				}

				INIT_LIST_HEAD(&tmp->list);

				tmp->thread = p;

				tmp->thread = p;

				list_add(&tmp->list, &thread_list);

				list_add(&tmp->list, &thread_list);

			}

			}

		while_each_thread(g,p);

		while_each_thread(g,p);

		read_unlock(&tasklist_lock);

		rcu_read_unlock();

		list_for_each(t, &thread_list) {

		list_for_each(t, &thread_list) {

			struct elf_thread_status *tmp;

			struct elf_thread_status *tmp;

			int sz;

			int sz;