[PATCH 4/5] proc: use down_read_killable for /proc/pid/clear_refs

Konstantin Khlebnikov
2019-05-15T08:41:28Z

Replace the only unkillable mmap_sem lock in clear_refs_write.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
fs/proc/task_mmu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 78bed6adc62d..7f84d1477b5b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1140,7 +1140,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
goto out_mm;
}

- down_read(&mm->mmap_sem);
+ if (down_read_killable(&mm->mmap_sem)) {
+ count = -EINTR;
+ goto out_mm;
+ }
tlb_gather_mmu(&tlb, mm, 0, -1);
if (type == CLEAR_REFS_SOFT_DIRTY) {
for (vma = mm->mmap; vma; vma = vma->vm_next) {