The patch titled
elf_core_dump: don't take tasklist_lock
has been removed from the -mm tree. Its filename is
elf_core_dump-dont-take-tasklist_lock.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: elf_core_dump: don't take tasklist_lock
From: Oleg Nesterov <oleg@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/binfmt_elf.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff -puN fs/binfmt_elf.c~elf_core_dump-dont-take-tasklist_lock fs/binfmt_elf.c
--- a/fs/binfmt_elf.c~elf_core_dump-dont-take-tasklist_lock
+++ a/fs/binfmt_elf.c
@@ -1479,20 +1479,19 @@ static int elf_core_dump(long signr, str
if (signr) {
struct elf_thread_status *tmp;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
do_each_thread(g,p)
if (current->mm == p->mm && current != p) {
tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
if (!tmp) {
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
goto cleanup;
}
- INIT_LIST_HEAD(&tmp->list);
tmp->thread = p;
list_add(&tmp->list, &thread_list);
}
while_each_thread(g,p);
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
list_for_each(t, &thread_list) {
struct elf_thread_status *tmp;
int sz;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
git-block.patch
proc-readdir-race-fix-take-3-race-fix.patch
vt-rework-the-console-spawning-variables.patch
vt-make-vt_pid-a-struct-pid-making-it-pid-wrap-around-safe.patch
simplify-pid-iterators.patch
file-add-locking-to-f_getown.patch
proc-convert-task_sig-to-use-lock_task_sighand.patch
proc-convert-do_task_stat-to-use-lock_task_sighand.patch
proc-drop-tasklist-lock-in-task_state.patch
proc-properly-compute-tgid_offset.patch
proc-remove-trailing-blank-entry-from-pid_entry-arrays.patch
proc-remove-the-useless-smp-safe-comments-from-proc.patch
proc-comment-what-proc_fill_cache-does.patch
introduce-get_task_pid-to-fix-unsafe-get_pid.patch
rcu-simplify-improve-batch-tuning.patch
pidhash-temporary-debug-checks.patch
-
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