Thread (68 messages) 68 messages, 8 authors, 2016-03-11

Re: [PATCH 07/18] mm, proc: make clear_refs killable

From: Oleg Nesterov <oleg@redhat.com>
Date: 2016-02-29 17:38:58
Also in: linux-mm, lkml

On 02/29, Michal Hocko wrote:
quoted hunk ↗ jump to hunk
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1027,11 +1027,15 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 		};

 		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
+			if (down_write_killable(&mm->mmap_sem)) {
+				put_task_struct(task);
+				return -EINTR;
+			}
+
 			/*
 			 * Writing 5 to /proc/pid/clear_refs resets the peak
 			 * resident set size to this mm's current rss value.
 			 */
-			down_write(&mm->mmap_sem);
 			reset_mm_hiwater_rss(mm);
 			up_write(&mm->mmap_sem);
 			goto out_mm;
@@ -1043,7 +1047,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				if (!(vma->vm_flags & VM_SOFTDIRTY))
 					continue;
 				up_read(&mm->mmap_sem);
-				down_write(&mm->mmap_sem);
+				if (down_write_killable(&mm->mmap_sem)) {
+					put_task_struct(task);
+					return -EINTR;
+				}
Both lack mmput() afaics. Don't you need "goto out_mm" rather then "return" ? In
this case you do not need put_task_struct().

Oleg.
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