[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <11cb9a09-f66c-4c46-bd38-fc6080413c29@I-love.SAKURA.ne.jp>
Date: Sat, 28 Jun 2025 17:36:00 +0900
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To: Jens Axboe <axboe@...nel.dk>, Yu Kuai <yukuai3@...wei.com>,
Christoph Hellwig <hch@....de>, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] brd: fix sleeping memory allocation in brd_insert_page()
syzbot is reporting that brd_insert_page() is calling
__xa_cmpxchg(__GFP_DIRECT_RECLAIM) with spinlock and RCU lock held.
Change __xa_cmpxchg() to use GFP_NOWAIT | __GFP_NOWARN, for it is likely
that __xa_cmpxchg() succeeds because of preceding alloc_page().
Fixes: bbcacab2e8ee ("brd: avoid extra xarray lookups on first write")
Reported-by: syzbot+ea4c8fd177a47338881a@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ea4c8fd177a47338881a
Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
---
drivers/block/brd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index b1be6c510372..ed3eb931750c 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -70,7 +70,7 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector,
xa_lock(&brd->brd_pages);
ret = __xa_cmpxchg(&brd->brd_pages, sector >> PAGE_SECTORS_SHIFT, NULL,
- page, gfp);
+ page, GFP_NOWAIT | __GFP_NOWARN);
if (ret) {
xa_unlock(&brd->brd_pages);
__free_page(page);
--
2.50.0
Powered by blists - more mailing lists