The patch titled
Subject: mm/linux-next: Fix rcu locking in vm_is_stack
has been removed from the -mm tree. Its filename was
procfs-mark-thread-stack-correctly-in-proc-pid-fix-rcu-locking-in-vm_is_stack.patch
This patch was dropped because it was nacked
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
From: Siddhesh Poyarekar <siddhesh.poyarekar@xxxxxxxxx>
Subject: mm/linux-next: Fix rcu locking in vm_is_stack
Take rcu read lock before we do anything at all with the threadgroup list.
Also use list_first_entry_rcu to safely get the reference to the first
task in the list.
Signed-off-by: Siddhesh Poyarekar <siddhesh.poyarekar@xxxxxxxxx>
Cc: Mark Salter <msalter@xxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff -puN mm/memory.c~procfs-mark-thread-stack-correctly-in-proc-pid-fix-rcu-locking-in-vm_is_stack mm/memory.c
--- a/mm/memory.c~procfs-mark-thread-stack-correctly-in-proc-pid-fix-rcu-locking-in-vm_is_stack
+++ a/mm/memory.c
@@ -3914,18 +3914,20 @@ pid_t vm_is_stack(struct task_struct *ta
return task->pid;
if (in_group) {
- struct task_struct *t = task;
+ struct task_struct *t;
rcu_read_lock();
- while_each_thread(task, t) {
+ t = list_first_entry_rcu(&task->thread_group,
+ struct task_struct, thread_group);
+ do {
if (vm_is_stack_for_task(t, vma)) {
ret = t->pid;
goto done;
}
- }
+ } while_each_thread(task, t);
+done:
+ rcu_read_unlock();
}
-done:
- rcu_read_unlock();
return ret;
}
_
Patches currently in -mm which might be from siddhesh.poyarekar@xxxxxxxxx are
linux-next.patch
procfs-mark-thread-stack-correctly-in-proc-pid-maps.patch
procfs-mark-thread-stack-correctly-in-proc-pid-maps-fix-task_nommu-build-regression-in-linux-next.patch
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