From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 16 Mar 2021 19:58:05 +0000 (-0400)
Subject: task_mmu rcu fix
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e011cc81666d7dd04f93f8979356b8fcdf6f0b82;p=users%2Fjedix%2Flinux-maple.git

task_mmu rcu fix

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 5dec40a64023..e1b6c070a5c7 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1241,12 +1241,14 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 		}
 		tlb_gather_mmu(&tlb, mm, 0, -1);
 		if (type == CLEAR_REFS_SOFT_DIRTY) {
+			mas_lock(&mas);
 			mas_for_each(&mas, vma, ULONG_MAX) {
 				if (!(vma->vm_flags & VM_SOFTDIRTY))
 					continue;
 				mmap_read_unlock(mm);
 				if (mmap_write_lock_killable(mm)) {
 					count = -EINTR;
+					mas_unlock(&mas);
 					goto out_mm;
 				}
 				mas_set(&mas, 0);
@@ -1257,6 +1259,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				mmap_write_downgrade(mm);
 				break;
 			}
+			mas_unlock(&mas);
 
 			mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
 						0, NULL, mm, 0, -1UL);