The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Thanks, Sasha

------------------ original commit in Linus's tree ------------------

From a30f895ad3239f45012e860d4f94c1a388b36d14 Mon Sep 17 00:00:00 2001

From: Jens Axboe axboe@kernel.dk Date: Fri, 20 Aug 2021 14:53:59 -0600 Subject: [PATCH] io_uring: fix xa_alloc_cycle() error return value check

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@vger.kernel.org Fixes: 61cf93700fe6 ("io_uring: Convert personality_idr to XArray") Signed-off-by: Jens Axboe axboe@kernel.dk --- fs/io_uring.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c index 979941bcd15a..a2e20a6fbfed 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -9843,10 +9843,11 @@ static int io_register_personality(struct io_ring_ctx *ctx)

ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds, XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL); - if (!ret) - return id; - put_cred(creds); - return ret; + if (ret < 0) { + put_cred(creds); + return ret; + } + return id; }

static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,