From: Nicholas Bellinger nab@linux-iscsi.org
Hi Sasha,
Here are two target patches for v4.1.y stable, which did not apply due to minor context changes.
The series has been cut against v4.1.48. Please apply at your earliest convenience.
Thank you,
--nab
Nicholas Bellinger (2): iscsi-target: Make TASK_REASSIGN use proper se_cmd->cmd_kref target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK
drivers/target/iscsi/iscsi_target.c | 20 +++++++------------- drivers/target/target_core_tmr.c | 9 +++++++++ drivers/target/target_core_transport.c | 2 ++ include/target/target_core_base.h | 1 + 4 files changed, 19 insertions(+), 13 deletions(-)
From: Nicholas Bellinger nab@linux-iscsi.org
commit ae072726f6109bb1c94841d6fb3a82dde298ea85 upstream.
Since commit 59b6986dbf fixed a potential NULL pointer dereference by allocating a se_tmr_req for ISCSI_TM_FUNC_TASK_REASSIGN, the se_tmr_req is currently leaked by iscsit_free_cmd() because no iscsi_cmd->se_cmd.se_tfo was associated.
To address this, treat ISCSI_TM_FUNC_TASK_REASSIGN like any other TMR and call transport_init_se_cmd() + target_get_sess_cmd() to setup iscsi_cmd->se_cmd.se_tfo with se_cmd->cmd_kref of 2.
This will ensure normal release operation once se_cmd->cmd_kref reaches zero and target_release_cmd_kref() is invoked, se_tmr_req will be released via existing target_free_cmd_mem() and core_tmr_release_req() code.
Reported-by: Donald White dew@datera.io Cc: Donald White dew@datera.io Cc: Mike Christie mchristi@redhat.com Cc: Hannes Reinecke hare@suse.com Signed-off-by: Nicholas Bellinger nab@linux-iscsi.org --- drivers/target/iscsi/iscsi_target.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 8df1ff3..8a5bcda 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -1754,7 +1754,6 @@ iscsit_handle_task_mgt_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd, struct iscsi_tmr_req *tmr_req; struct iscsi_tm *hdr; int out_of_order_cmdsn = 0, ret; - bool sess_ref = false; u8 function, tcm_function = TMR_UNKNOWN;
hdr = (struct iscsi_tm *) buf; @@ -1796,18 +1795,17 @@ iscsit_handle_task_mgt_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd, buf); }
+ transport_init_se_cmd(&cmd->se_cmd, &iscsi_ops, + conn->sess->se_sess, 0, DMA_NONE, + TCM_SIMPLE_TAG, cmd->sense_buffer + 2); + + target_get_sess_cmd(&cmd->se_cmd, true); + /* * TASK_REASSIGN for ERL=2 / connection stays inside of * LIO-Target $FABRIC_MOD */ if (function != ISCSI_TM_FUNC_TASK_REASSIGN) { - transport_init_se_cmd(&cmd->se_cmd, &iscsi_ops, - conn->sess->se_sess, 0, DMA_NONE, - TCM_SIMPLE_TAG, cmd->sense_buffer + 2); - - target_get_sess_cmd(&cmd->se_cmd, true); - sess_ref = true; - switch (function) { case ISCSI_TM_FUNC_ABORT_TASK: tcm_function = TMR_ABORT_TASK; @@ -1946,12 +1944,8 @@ attach: * For connection recovery, this is also the default action for * TMR TASK_REASSIGN. */ - if (sess_ref) { - pr_debug("Handle TMR, using sess_ref=true check\n"); - target_put_sess_cmd(&cmd->se_cmd); - } - iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state); + target_put_sess_cmd(&cmd->se_cmd); return 0; } EXPORT_SYMBOL(iscsit_handle_task_mgt_cmd);
From: Nicholas Bellinger nab@linux-iscsi.org
commit 1c21a48055a67ceb693e9c2587824a8de60a217c upstream.
This patch fixes bug where early se_cmd exceptions that occur before backend execution can result in use-after-free if/when a subsequent ABORT_TASK occurs for the same tag.
Since an early se_cmd exception will have had se_cmd added to se_session->sess_cmd_list via target_get_sess_cmd(), it will not have CMD_T_COMPLETE set by the usual target_complete_cmd() backend completion path.
This causes a subsequent ABORT_TASK + __target_check_io_state() to signal ABORT_TASK should proceed. As core_tmr_abort_task() executes, it will bring the outstanding se_cmd->cmd_kref count down to zero releasing se_cmd, after se_cmd has already been queued with error status into fabric driver response path code.
To address this bug, introduce a CMD_T_PRE_EXECUTE bit that is set at target_get_sess_cmd() time, and cleared immediately before backend driver dispatch in target_execute_cmd() once CMD_T_ACTIVE is set.
Then, check CMD_T_PRE_EXECUTE within __target_check_io_state() to determine when an early exception has occured, and avoid aborting this se_cmd since it will have already been queued into fabric driver response path code.
Reported-by: Donald White dew@datera.io Cc: Donald White dew@datera.io Cc: Mike Christie mchristi@redhat.com Cc: Hannes Reinecke hare@suse.com Signed-off-by: Nicholas Bellinger nab@linux-iscsi.org --- drivers/target/target_core_tmr.c | 9 +++++++++ drivers/target/target_core_transport.c | 2 ++ include/target/target_core_base.h | 1 + 3 files changed, 12 insertions(+)
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c index 44510bd..03a73d5 100644 --- a/drivers/target/target_core_tmr.c +++ b/drivers/target/target_core_tmr.c @@ -137,6 +137,15 @@ static bool __target_check_io_state(struct se_cmd *se_cmd, spin_unlock(&se_cmd->t_state_lock); return false; } + if (se_cmd->transport_state & CMD_T_PRE_EXECUTE) { + if (se_cmd->scsi_status) { + pr_debug("Attempted to abort io tag: %u early failure" + " status: 0x%02x\n", se_cmd->se_tfo->get_task_tag(se_cmd), + se_cmd->scsi_status); + spin_unlock(&se_cmd->t_state_lock); + return false; + } + } if (sess->sess_tearing_down || se_cmd->cmd_wait_set) { pr_debug("Attempted to abort io tag: %u already shutdown," " skipping\n", se_cmd->se_tfo->get_task_tag(se_cmd)); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 958b0dc..32593d8 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1899,6 +1899,7 @@ void target_execute_cmd(struct se_cmd *cmd) }
cmd->t_state = TRANSPORT_PROCESSING; + cmd->transport_state &= ~CMD_T_PRE_EXECUTE; cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT; spin_unlock_irq(&cmd->t_state_lock);
@@ -2543,6 +2544,7 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref) ret = -ESHUTDOWN; goto out; } + se_cmd->transport_state |= CMD_T_PRE_EXECUTE; list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list); out: spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index ad3c146..c654d9e 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -541,6 +541,7 @@ struct se_cmd { #define CMD_T_BUSY (1 << 9) #define CMD_T_TAS (1 << 10) #define CMD_T_FABRIC_STOP (1 << 11) +#define CMD_T_PRE_EXECUTE (1 << 12) spinlock_t t_state_lock; struct completion t_transport_stop_comp;
linux-stable-mirror@lists.linaro.org
-
Nicholas A. Bellinger