From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Finn Thain , "Martin K. Petersen" Subject: [PATCH 4.5 040/238] ncr5380: Dont re-enter NCR5380_select() Date: Sun, 10 Apr 2016 11:33:37 -0700 Message-Id: <20160410183458.573074769@linuxfoundation.org> In-Reply-To: <20160410183456.398741366@linuxfoundation.org> References: <20160410183456.398741366@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Finn Thain commit 71a00593ec0c2e2c1720e4041cf2926ff1d07826 upstream. Calling NCR5380_select() from the abort handler causes various problems. Firstly, it means potentially re-entering NCR5380_select(). Secondly, it means that the lock is released, which permits the EH handlers to be re-entered. The combination results in crashes. Don't do it. Fixes: 8b00c3d5d40d ("ncr5380: Implement new eh_abort_handler") Reported-and-tested-by: Michael Schmitz Signed-off-by: Finn Thain Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/NCR5380.c | 16 ++++++++-------- drivers/scsi/atari_NCR5380.c | 16 ++++++++-------- 2 files changed, 16 insertions(+), 16 deletions(-) --- a/drivers/scsi/NCR5380.c +++ b/drivers/scsi/NCR5380.c @@ -2302,6 +2302,9 @@ static bool list_del_cmd(struct list_hea * If cmd was not found at all then presumably it has already been completed, * in which case return SUCCESS to try to avoid further EH measures. * If the command has not completed yet, we must not fail to find it. + * + * The lock protects driver data structures, but EH handlers also use it + * to serialize their own execution and prevent their own re-entry. */ static int NCR5380_abort(struct scsi_cmnd *cmd) @@ -2338,14 +2341,11 @@ static int NCR5380_abort(struct scsi_cmn if (list_del_cmd(&hostdata->disconnected, cmd)) { dsprintk(NDEBUG_ABORT, instance, "abort: removed %p from disconnected list\n", cmd); - cmd->result = DID_ERROR << 16; - if (!hostdata->connected) - NCR5380_select(instance, cmd); - if (hostdata->connected != cmd) { - complete_cmd(instance, cmd); - result = FAILED; - goto out; - } + /* Can't call NCR5380_select() and send ABORT because that + * means releasing the lock. Need a bus reset. + */ + result = FAILED; + goto out; } if (hostdata->connected == cmd) { --- a/drivers/scsi/atari_NCR5380.c +++ b/drivers/scsi/atari_NCR5380.c @@ -2497,6 +2497,9 @@ static bool list_del_cmd(struct list_hea * If cmd was not found at all then presumably it has already been completed, * in which case return SUCCESS to try to avoid further EH measures. * If the command has not completed yet, we must not fail to find it. + * + * The lock protects driver data structures, but EH handlers also use it + * to serialize their own execution and prevent their own re-entry. */ static int NCR5380_abort(struct scsi_cmnd *cmd) @@ -2533,14 +2536,11 @@ static int NCR5380_abort(struct scsi_cmn if (list_del_cmd(&hostdata->disconnected, cmd)) { dsprintk(NDEBUG_ABORT, instance, "abort: removed %p from disconnected list\n", cmd); - cmd->result = DID_ERROR << 16; - if (!hostdata->connected) - NCR5380_select(instance, cmd); - if (hostdata->connected != cmd) { - complete_cmd(instance, cmd); - result = FAILED; - goto out; - } + /* Can't call NCR5380_select() and send ABORT because that + * means releasing the lock. Need a bus reset. + */ + result = FAILED; + goto out; } if (hostdata->connected == cmd) {