All of lore.kernel.org
 help / color / mirror / Atom feed
From: Chao Yu <yuchao0@huawei.com>
To: <jaegeuk@kernel.org>
Cc: <linux-f2fs-devel@lists.sourceforge.net>,
	<linux-kernel@vger.kernel.org>, <chao@kernel.org>,
	Chao Yu <yuchao0@huawei.com>
Subject: [PATCH v2] f2fs: prevent waiter encountering incorrect discard states
Date: Wed, 5 Apr 2017 18:26:26 +0800	[thread overview]
Message-ID: <20170405102626.60148-1-yuchao0@huawei.com> (raw)

In f2fs_submit_discard_endio, we will wake up waiter before setting
discard command states, so waiter may use incorrect states. Change
the order between complete() and states setting to fix this issue.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
v2: use wait_for_completion_io before releasing discard entry to avoid
use-after-free.
 fs/f2fs/segment.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 24911c5679d6..ec19cfcfcd24 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -717,9 +717,9 @@ static void f2fs_submit_discard_endio(struct bio *bio)
 {
 	struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
 
-	complete(&dc->wait);
 	dc->error = bio->bi_error;
 	dc->state = D_DONE;
+	complete(&dc->wait);
 	bio_put(bio);
 }
 
@@ -807,8 +807,7 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
 
 	list_for_each_entry_safe(dc, tmp, wait_list, list) {
 		if (dc->lstart <= blkaddr && blkaddr < dc->lstart + dc->len) {
-			if (dc->state == D_SUBMIT)
-				wait_for_completion_io(&dc->wait);
+			wait_for_completion_io(&dc->wait);
 			__punch_discard_cmd(sbi, dc, blkaddr);
 		}
 	}
@@ -868,8 +867,10 @@ static int issue_discard_thread(void *data)
 	blk_finish_plug(&plug);
 
 	list_for_each_entry_safe(dc, tmp, wait_list, list) {
-		if (dc->state == D_DONE)
+		if (dc->state == D_DONE) {
+			wait_for_completion_io(&dc->wait);
 			__remove_discard_cmd(sbi, dc);
+		}
 	}
 	mutex_unlock(&dcc->cmd_lock);
 
-- 
2.12.2.510.ge1104a5ee539

WARNING: multiple messages have this Message-ID (diff)
From: Chao Yu <yuchao0@huawei.com>
To: jaegeuk@kernel.org
Cc: chao@kernel.org, linux-kernel@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net
Subject: [PATCH v2] f2fs: prevent waiter encountering incorrect discard states
Date: Wed, 5 Apr 2017 18:26:26 +0800	[thread overview]
Message-ID: <20170405102626.60148-1-yuchao0@huawei.com> (raw)

In f2fs_submit_discard_endio, we will wake up waiter before setting
discard command states, so waiter may use incorrect states. Change
the order between complete() and states setting to fix this issue.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
v2: use wait_for_completion_io before releasing discard entry to avoid
use-after-free.
 fs/f2fs/segment.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 24911c5679d6..ec19cfcfcd24 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -717,9 +717,9 @@ static void f2fs_submit_discard_endio(struct bio *bio)
 {
 	struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
 
-	complete(&dc->wait);
 	dc->error = bio->bi_error;
 	dc->state = D_DONE;
+	complete(&dc->wait);
 	bio_put(bio);
 }
 
@@ -807,8 +807,7 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
 
 	list_for_each_entry_safe(dc, tmp, wait_list, list) {
 		if (dc->lstart <= blkaddr && blkaddr < dc->lstart + dc->len) {
-			if (dc->state == D_SUBMIT)
-				wait_for_completion_io(&dc->wait);
+			wait_for_completion_io(&dc->wait);
 			__punch_discard_cmd(sbi, dc, blkaddr);
 		}
 	}
@@ -868,8 +867,10 @@ static int issue_discard_thread(void *data)
 	blk_finish_plug(&plug);
 
 	list_for_each_entry_safe(dc, tmp, wait_list, list) {
-		if (dc->state == D_DONE)
+		if (dc->state == D_DONE) {
+			wait_for_completion_io(&dc->wait);
 			__remove_discard_cmd(sbi, dc);
+		}
 	}
 	mutex_unlock(&dcc->cmd_lock);
 
-- 
2.12.2.510.ge1104a5ee539


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot

             reply	other threads:[~2017-04-05 10:27 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-05 10:26 Chao Yu [this message]
2017-04-05 10:26 ` [PATCH v2] f2fs: prevent waiter encountering incorrect discard states Chao Yu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170405102626.60148-1-yuchao0@huawei.com \
    --to=yuchao0@huawei.com \
    --cc=chao@kernel.org \
    --cc=jaegeuk@kernel.org \
    --cc=linux-f2fs-devel@lists.sourceforge.net \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.