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Commit bce9a234ce7d8dddbfcec28e37ea58b5d8f6003d

Authored by Oleg Nesterov
Committed by Linus Torvalds
1 parent 486ccb05fd
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[PATCH] elf_fdpic_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: Oleg Nesterov <oleg@tv-sign.ru>
Acked-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 1 changed file with 3 additions and 4 deletions Side-by-side Diff

fs/binfmt_elf_fdpic.c
Diff comments   View file @ bce9a23
... ... @@ -1597,20 +1597,19 @@
1597 1597  
1598 1598 if (signr) {
1599 1599 struct elf_thread_status *tmp;
1600   - read_lock(&tasklist_lock);
  1600 + rcu_read_lock();
1601 1601 do_each_thread(g,p)
1602 1602 if (current->mm == p->mm && current != p) {
1603 1603 tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
1604 1604 if (!tmp) {
1605   - read_unlock(&tasklist_lock);
  1605 + rcu_read_unlock();
1606 1606 goto cleanup;
1607 1607 }
1608   - INIT_LIST_HEAD(&tmp->list);
1609 1608 tmp->thread = p;
1610 1609 list_add(&tmp->list, &thread_list);
1611 1610 }
1612 1611 while_each_thread(g,p);
1613   - read_unlock(&tasklist_lock);
  1612 + rcu_read_unlock();
1614 1613 list_for_each(t, &thread_list) {
1615 1614 struct elf_thread_status *tmp;
1616 1615 int sz;