linux-kernel - [PATCH 5.10 96/98] io_uring: fix xa_alloc

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Message-Id: <20210824165908.709932-97-sashal@kernel.org>
Date:   Tue, 24 Aug 2021 12:59:06 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jens Axboe <axboe@...nel.dk>,
        Pavel Begunkov <asml.silence@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 96/98] io_uring: fix xa_alloc_cycle() error return value check

From: Jens Axboe <axboe@...nel.dk>

[ upstream commit a30f895ad3239f45012e860d4f94c1a388b36d14 ]

We currently check for ret != 0 to indicate error, but '1' is a valid
return and just indicates that the allocation succeeded with a wrap.
Correct the check to be for < 0, like it was before the xarray
conversion.

Cc: stable@...r.kernel.org
Fixes: 61cf93700fe6 ("io_uring: Convert personality_idr to XArray")
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/io_uring.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ed641dca7957..762eae2440b5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -9601,11 +9601,12 @@ static int io_register_personality(struct io_ring_ctx *ctx)
 
 	ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)iod,
 			XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
-	if (!ret)
-		return id;
-	put_cred(iod->creds);
-	kfree(iod);
-	return ret;
+	if (ret < 0) {
+		put_cred(iod->creds);
+		kfree(iod);
+		return ret;
+	}
+	return id;
 }
 
 static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
-- 
2.30.2