From: SeongJae Park <sj@kernel.org>
To: stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, SeongJae Park <sj@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH for-5.15.x 2/2] mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
Date: Sun, 21 Nov 2021 11:02:11 +0000 [thread overview]
Message-ID: <20211121110211.17032-3-sj@kernel.org> (raw)
In-Reply-To: <20211121110211.17032-1-sj@kernel.org>
commit d78f3853f831eee46c6dbe726debf3be9e9c0d05 upstream.
DAMON debugfs is supposed to protect dbgfs_ctxs, dbgfs_nr_ctxs, and
dbgfs_dirs using damon_dbgfs_lock. However, some of the code is
accessing the variables without the protection. This fixes it by
protecting all such accesses.
Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@kernel.org
Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/damon/dbgfs.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 2741ff79e8e8..f94d19a690df 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -538,12 +538,14 @@ static ssize_t dbgfs_monitor_on_write(struct file *file,
return -EINVAL;
}
+ mutex_lock(&damon_dbgfs_lock);
if (!strncmp(kbuf, "on", count))
err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
else if (!strncmp(kbuf, "off", count))
err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
else
err = -EINVAL;
+ mutex_unlock(&damon_dbgfs_lock);
if (err)
ret = err;
@@ -596,15 +598,16 @@ static int __init __damon_dbgfs_init(void)
static int __init damon_dbgfs_init(void)
{
- int rc;
+ int rc = -ENOMEM;
+ mutex_lock(&damon_dbgfs_lock);
dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
if (!dbgfs_ctxs)
- return -ENOMEM;
+ goto out;
dbgfs_ctxs[0] = dbgfs_new_ctx();
if (!dbgfs_ctxs[0]) {
kfree(dbgfs_ctxs);
- return -ENOMEM;
+ goto out;
}
dbgfs_nr_ctxs = 1;
@@ -615,6 +618,8 @@ static int __init damon_dbgfs_init(void)
pr_err("%s: dbgfs init failed\n", __func__);
}
+out:
+ mutex_unlock(&damon_dbgfs_lock);
return rc;
}
--
2.17.1
next prev parent reply other threads:[~2021-11-21 11:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-21 11:02 [PATCH for-5.15.x 0/2] DAMON fixes SeongJae Park
2021-11-21 11:02 ` [PATCH for-5.15.x 1/2] mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation SeongJae Park
2021-11-21 11:02 ` SeongJae Park [this message]
2021-11-22 12:28 ` [PATCH for-5.15.x 0/2] DAMON fixes Greg KH
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