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 1/2] mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation
Date: Sun, 21 Nov 2021 11:02:10 +0000 [thread overview]
Message-ID: <20211121110211.17032-2-sj@kernel.org> (raw)
In-Reply-To: <20211121110211.17032-1-sj@kernel.org>
commit db7a347b26fe05d2e8c115bb24dfd908d0252bc3 upstream.
Patch series "DAMON fixes".
This patch (of 2):
DAMON users can trigger below warning in '__alloc_pages()' by invoking
write() to some DAMON debugfs files with arbitrarily high count
argument, because DAMON debugfs interface allocates some buffers based
on the user-specified 'count'.
if (unlikely(order >= MAX_ORDER)) {
WARN_ON_ONCE(!(gfp & __GFP_NOWARN));
return NULL;
}
Because the DAMON debugfs interface code checks failure of the
'kmalloc()', this commit simply suppresses the warnings by adding
'__GFP_NOWARN' flag.
Link: https://lkml.kernel.org/r/20211110145758.16558-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211110145758.16558-2-sj@kernel.org
Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
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 | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index faee070977d8..2741ff79e8e8 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -32,7 +32,7 @@ static char *user_input_str(const char __user *buf, size_t count, loff_t *ppos)
if (*ppos)
return ERR_PTR(-EINVAL);
- kbuf = kmalloc(count + 1, GFP_KERNEL);
+ kbuf = kmalloc(count + 1, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return ERR_PTR(-ENOMEM);
@@ -247,7 +247,7 @@ static ssize_t dbgfs_kdamond_pid_read(struct file *file,
char *kbuf;
ssize_t len;
- kbuf = kmalloc(count, GFP_KERNEL);
+ kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
--
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 ` SeongJae Park [this message]
2021-11-21 11:02 ` [PATCH for-5.15.x 2/2] mm/damon/dbgfs: fix missed use of damon_dbgfs_lock SeongJae Park
2021-11-22 12:28 ` [PATCH for-5.15.x 0/2] DAMON fixes Greg KH
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