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* [PATCH][next] io_uring: Fix a read of ununitialized pointer tctx
@ 2021-09-03 11:35 Colin King
  2021-09-03 12:16 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2021-09-03 11:35 UTC (permalink / raw)
  To: Jens Axboe, Pavel Begunkov, io-uring; +Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

In the unlikely case where ctx->flags & IORING_SETUP_SQPOLL is true
and sqd is NULL the pointer tctx is not assigned a valid value and
can contain a garbage value when it is dereferenced. Fix this by
initializing it to NULL.

Addresses-Coverity: ("Uninitialized pointer read")
Fixes: 9e30726065ea ("io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLL")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 132dd38e89ce..843362bebd8c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10525,7 +10525,7 @@ static int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
 					void __user *arg)
 {
 	struct io_sq_data *sqd = NULL;
-	struct io_uring_task *tctx;
+	struct io_uring_task *tctx = NULL;
 	__u32 new_count[2];
 	int i, ret;
 
-- 
2.32.0


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH][next] io_uring: Fix a read of ununitialized pointer tctx
  2021-09-03 11:35 [PATCH][next] io_uring: Fix a read of ununitialized pointer tctx Colin King
@ 2021-09-03 12:16 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2021-09-03 12:16 UTC (permalink / raw)
  To: Colin King, Pavel Begunkov, io-uring; +Cc: kernel-janitors, linux-kernel

On 9/3/21 5:35 AM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> In the unlikely case where ctx->flags & IORING_SETUP_SQPOLL is true
> and sqd is NULL the pointer tctx is not assigned a valid value and
> can contain a garbage value when it is dereferenced. Fix this by
> initializing it to NULL.

Doh - thanks, I folded this one in.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 2+ messages in thread

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