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From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
To: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Cc: Cyrill Gorcunov <gorcunov@gmail.com>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 1/5] proc: use down_read_killable for /proc/pid/maps
Date: Wed, 15 May 2019 11:41:12 +0300
Message-ID: <155790967258.1319.11531787078240675602.stgit@buzz> (raw)

Do not stuck forever if something wrong.
This function also used for /proc/pid/smaps.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 fs/proc/task_mmu.c   |    6 +++++-
 fs/proc/task_nommu.c |    6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 01d4eb0e6bd1..2bf210229daf 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -166,7 +166,11 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
 	if (!mm || !mmget_not_zero(mm))
 		return NULL;
 
-	down_read(&mm->mmap_sem);
+	if (down_read_killable(&mm->mmap_sem)) {
+		mmput(mm);
+		return ERR_PTR(-EINTR);
+	}
+
 	hold_task_mempolicy(priv);
 	priv->tail_vma = get_gate_vma(mm);
 
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 36bf0f2e102e..7907e6419e57 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -211,7 +211,11 @@ static void *m_start(struct seq_file *m, loff_t *pos)
 	if (!mm || !mmget_not_zero(mm))
 		return NULL;
 
-	down_read(&mm->mmap_sem);
+	if (down_read_killable(&mm->mmap_sem)) {
+		mmput(mm);
+		return ERR_PTR(-EINTR);
+	}
+
 	/* start from the Nth VMA */
 	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
 		if (n-- == 0)


             reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-15  8:41 Konstantin Khlebnikov [this message]
2019-05-15  8:41 ` [PATCH 2/5] proc: use down_read_killable for /proc/pid/smaps_rollup Konstantin Khlebnikov
2019-05-17 12:45   ` Michal Hocko
2019-06-09  9:07     ` Konstantin Khlebnikov
2019-06-10 18:58       ` Michal Hocko
2019-05-15  8:41 ` [PATCH 3/5] proc: use down_read_killable for /proc/pid/pagemap Konstantin Khlebnikov
2019-05-17 12:46   ` Michal Hocko
2019-05-15  8:41 ` [PATCH 4/5] proc: use down_read_killable for /proc/pid/clear_refs Konstantin Khlebnikov
2019-05-17 12:47   ` Michal Hocko
2019-05-15  8:41 ` [PATCH 5/5] proc: use down_read_killable for /proc/pid/map_files Konstantin Khlebnikov
2019-05-15 17:00   ` Roman Gushchin
2019-05-15  9:05 ` [PATCH 1/5] proc: use down_read_killable for /proc/pid/maps Cyrill Gorcunov
2019-05-15  9:16 ` Kirill Tkhai
2019-05-17 12:41 ` Michal Hocko

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