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Message-ID: <812e1f64-14b4-20da-575c-ad763199e1a4@redhat.com>
Date:   Thu, 28 Jul 2022 09:17:05 -0400
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Subject: Re: [PATCH 1/2] clnt_dg_freeres() uncleared set active state may
 deadlock.
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To:     Attila Kovacs <attila.kovacs@cfa.harvard.edu>,
        Libtirpc-devel Mailing List 
        <libtirpc-devel@lists.sourceforge.net>
Cc:     Linux NFS Mailing list <linux-nfs@vger.kernel.org>
References: <20220726141906.69023-1-attila.kovacs@cfa.harvard.edu>
From:   Steve Dickson <steved@redhat.com>
In-Reply-To: <20220726141906.69023-1-attila.kovacs@cfa.harvard.edu>
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On 7/26/22 10:19 AM, Attila Kovacs wrote:
> From: Attila Kovacs <attipaci@gmail.com>
> 
> In clnt_dg.c in clnt_dg_freeres(), cu_fd_lock->active is set to TRUE, with no
> corresponding clearing when the operation (*xdr_res() call) is completed. This
> would leave other waiting operations blocked indefinitely, effectively
> deadlocking the client. For comparison, clnt_vd_freeres() in clnt_vc.c does not
> set the active state to TRUE. I believe the vc behavior is correct, while the
> dg behavior is a bug.
> 
> Signed-off-by: Attila Kovacs <attipaci@gmail.com>
Committed (tag: libtirpc-1-3-3-rc4)

steved.
> ---
>   src/clnt_dg.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/src/clnt_dg.c b/src/clnt_dg.c
> index 7c5d22e..b2043ac 100644
> --- a/src/clnt_dg.c
> +++ b/src/clnt_dg.c
> @@ -573,7 +573,6 @@ clnt_dg_freeres(cl, xdr_res, res_ptr)
>   	mutex_lock(&clnt_fd_lock);
>   	while (cu->cu_fd_lock->active)
>   		cond_wait(&cu->cu_fd_lock->cv, &clnt_fd_lock);
> -	cu->cu_fd_lock->active = TRUE;
>   	xdrs->x_op = XDR_FREE;
>   	dummy = (*xdr_res)(xdrs, res_ptr);
>   	thr_sigsetmask(SIG_SETMASK, &mask, NULL);