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authorJunxiao Bi <junxiao.bi@oracle.com>2023-09-18 15:58:48 -0700
committerMartin K. Petersen <martin.petersen@oracle.com>2023-09-27 10:55:29 -0400
commita154f5f643c6ecddd44847217a7a3845b4350003 (patch)
tree59a251c80cf966a1d94b4b1d8e78a6fcfee23edb /drivers/target
parent2132df16f53b4f01ab25f5d404f36a22244ae342 (diff)
scsi: target: core: Fix deadlock due to recursive locking
The following call trace shows a deadlock issue due to recursive locking of mutex "device_mutex". First lock acquire is in target_for_each_device() and second in target_free_device(). PID: 148266 TASK: ffff8be21ffb5d00 CPU: 10 COMMAND: "iscsi_ttx" #0 [ffffa2bfc9ec3b18] __schedule at ffffffffa8060e7f #1 [ffffa2bfc9ec3ba0] schedule at ffffffffa8061224 #2 [ffffa2bfc9ec3bb8] schedule_preempt_disabled at ffffffffa80615ee #3 [ffffa2bfc9ec3bc8] __mutex_lock at ffffffffa8062fd7 #4 [ffffa2bfc9ec3c40] __mutex_lock_slowpath at ffffffffa80631d3 #5 [ffffa2bfc9ec3c50] mutex_lock at ffffffffa806320c #6 [ffffa2bfc9ec3c68] target_free_device at ffffffffc0935998 [target_core_mod] #7 [ffffa2bfc9ec3c90] target_core_dev_release at ffffffffc092f975 [target_core_mod] #8 [ffffa2bfc9ec3ca0] config_item_put at ffffffffa79d250f #9 [ffffa2bfc9ec3cd0] config_item_put at ffffffffa79d2583 #10 [ffffa2bfc9ec3ce0] target_devices_idr_iter at ffffffffc0933f3a [target_core_mod] #11 [ffffa2bfc9ec3d00] idr_for_each at ffffffffa803f6fc #12 [ffffa2bfc9ec3d60] target_for_each_device at ffffffffc0935670 [target_core_mod] #13 [ffffa2bfc9ec3d98] transport_deregister_session at ffffffffc0946408 [target_core_mod] #14 [ffffa2bfc9ec3dc8] iscsit_close_session at ffffffffc09a44a6 [iscsi_target_mod] #15 [ffffa2bfc9ec3df0] iscsit_close_connection at ffffffffc09a4a88 [iscsi_target_mod] #16 [ffffa2bfc9ec3df8] finish_task_switch at ffffffffa76e5d07 #17 [ffffa2bfc9ec3e78] iscsit_take_action_for_connection_exit at ffffffffc0991c23 [iscsi_target_mod] #18 [ffffa2bfc9ec3ea0] iscsi_target_tx_thread at ffffffffc09a403b [iscsi_target_mod] #19 [ffffa2bfc9ec3f08] kthread at ffffffffa76d8080 #20 [ffffa2bfc9ec3f50] ret_from_fork at ffffffffa8200364 Fixes: 36d4cb460bcb ("scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion") Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Link: https://lore.kernel.org/r/20230918225848.66463-1-junxiao.bi@oracle.com Reviewed-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_device.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index b7ac60f4a219..b6523d4b9259 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -843,7 +843,6 @@ sector_t target_to_linux_sector(struct se_device *dev, sector_t lb)
EXPORT_SYMBOL(target_to_linux_sector);
struct devices_idr_iter {
- struct config_item *prev_item;
int (*fn)(struct se_device *dev, void *data);
void *data;
};
@@ -853,11 +852,9 @@ static int target_devices_idr_iter(int id, void *p, void *data)
{
struct devices_idr_iter *iter = data;
struct se_device *dev = p;
+ struct config_item *item;
int ret;
- config_item_put(iter->prev_item);
- iter->prev_item = NULL;
-
/*
* We add the device early to the idr, so it can be used
* by backend modules during configuration. We do not want
@@ -867,12 +864,13 @@ static int target_devices_idr_iter(int id, void *p, void *data)
if (!target_dev_configured(dev))
return 0;
- iter->prev_item = config_item_get_unless_zero(&dev->dev_group.cg_item);
- if (!iter->prev_item)
+ item = config_item_get_unless_zero(&dev->dev_group.cg_item);
+ if (!item)
return 0;
mutex_unlock(&device_mutex);
ret = iter->fn(dev, iter->data);
+ config_item_put(item);
mutex_lock(&device_mutex);
return ret;
@@ -895,7 +893,6 @@ int target_for_each_device(int (*fn)(struct se_device *dev, void *data),
mutex_lock(&device_mutex);
ret = idr_for_each(&devices_idr, target_devices_idr_iter, &iter);
mutex_unlock(&device_mutex);
- config_item_put(iter.prev_item);
return ret;
}