From: Mike Christie <michael.christie@oracle.com>
To: Maurizio Lombardi <mlombard@redhat.com>, martin.petersen@oracle.com
Cc: target-devel@vger.kernel.org
Subject: Re: [PATCH V2 3/3] target: iscsi: prevent login threads from racing between each other
Date: Wed, 26 Apr 2023 10:44:27 -0500 [thread overview]
Message-ID: <792bbf44-f88d-7919-b7ce-09e30f9f347f@oracle.com> (raw)
In-Reply-To: <20230417171801.208122-4-mlombard@redhat.com>
On 4/17/23 12:18 PM, Maurizio Lombardi wrote:
> The tpg->np_login_sem is a semaphore that is used to serialize the login
> process when multiple login threads run concurrently against the same
> target portal group.
>
> The iscsi_target_locate_portal() function finds the tpg,
> calls iscsit_access_np() against the np_login_sem semaphore
> and saves the tpg pointer in conn->tpg;
>
> If iscsi_target_locate_portal() fails, the caller will check for the
> conn->tpg pointer and, if it's not NULL, then it will assume
> that iscsi_target_locate_portal() called iscsit_access_np() on the
> semaphore.
>
> Make sure that conn->tpg gets initialized only if iscsit_access_np()
> was successful, otherwise iscsit_deaccess_np() may end up
> being called against a semaphore we never took, allowing more than one
> thread to access the same tpg.
>
> Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
prev parent reply other threads:[~2023-04-26 15:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-17 17:17 [PATCH V2 0/3] Fix possible hangs and race conditions during login Maurizio Lombardi
2023-04-17 17:17 ` [PATCH V2 1/3] target: iscsi: fix hang in the iSCSI login code Maurizio Lombardi
2023-04-26 15:35 ` Mike Christie
2023-04-26 15:39 ` Mike Christie
2023-04-17 17:18 ` [PATCH V2 2/3] target: iscsi: remove unused transport_timer Maurizio Lombardi
2023-04-26 15:43 ` Mike Christie
2023-04-17 17:18 ` [PATCH V2 3/3] target: iscsi: prevent login threads from racing between each other Maurizio Lombardi
2023-04-26 15:44 ` Mike Christie [this message]
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