[PATCH AUTOSEL 4.20 059/117] scsi: target/core: Make sure that target_wait_for_sess_cmds() waits long enough
From: Sasha Levin
Date: Tue Jan 08 2019 - 14:28:20 EST
From: Bart Van Assche <bvanassche@xxxxxxx>
[ Upstream commit ad669505c4e9db9af9faeb5c51aa399326a80d91 ]
A session must only be released after all code that accesses the session
structure has finished. Make sure that this is the case by introducing a
new command counter per session that is only decremented after the
.release_cmd() callback has finished. This patch fixes the following crash:
BUG: KASAN: use-after-free in do_raw_spin_lock+0x1c/0x130
Read of size 4 at addr ffff8801534b16e4 by task rmdir/14805
CPU: 16 PID: 14805 Comm: rmdir Not tainted 4.18.0-rc2-dbg+ #5
Call Trace:
dump_stack+0xa4/0xf5
print_address_description+0x6f/0x270
kasan_report+0x241/0x360
__asan_load4+0x78/0x80
do_raw_spin_lock+0x1c/0x130
_raw_spin_lock_irqsave+0x52/0x60
srpt_set_ch_state+0x27/0x70 [ib_srpt]
srpt_disconnect_ch+0x1b/0xc0 [ib_srpt]
srpt_close_session+0xa8/0x260 [ib_srpt]
target_shutdown_sessions+0x170/0x180 [target_core_mod]
core_tpg_del_initiator_node_acl+0xf3/0x200 [target_core_mod]
target_fabric_nacl_base_release+0x25/0x30 [target_core_mod]
config_item_release+0x9c/0x110 [configfs]
config_item_put+0x26/0x30 [configfs]
configfs_rmdir+0x3b8/0x510 [configfs]
vfs_rmdir+0xb3/0x1e0
do_rmdir+0x262/0x2c0
do_syscall_64+0x77/0x230
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Cc: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Cc: Mike Christie <mchristi@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: David Disseldorp <ddiss@xxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/target/target_core_transport.c | 35 ++++++++++++++++++--------
drivers/target/target_core_xcopy.c | 6 ++++-
include/target/target_core_base.h | 1 +
include/target/target_core_fabric.h | 2 +-
4 files changed, 32 insertions(+), 12 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 2cfd61d62e97..ffa5b9f771b5 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -224,19 +224,28 @@ void transport_subsystem_check_init(void)
sub_api_initialized = 1;
}
+static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
+{
+ struct se_session *sess = container_of(ref, typeof(*sess), cmd_count);
+
+ wake_up(&sess->cmd_list_wq);
+}
+
/**
* transport_init_session - initialize a session object
* @se_sess: Session object pointer.
*
* The caller must have zero-initialized @se_sess before calling this function.
*/
-void transport_init_session(struct se_session *se_sess)
+int transport_init_session(struct se_session *se_sess)
{
INIT_LIST_HEAD(&se_sess->sess_list);
INIT_LIST_HEAD(&se_sess->sess_acl_list);
INIT_LIST_HEAD(&se_sess->sess_cmd_list);
spin_lock_init(&se_sess->sess_cmd_lock);
init_waitqueue_head(&se_sess->cmd_list_wq);
+ return percpu_ref_init(&se_sess->cmd_count,
+ target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
}
EXPORT_SYMBOL(transport_init_session);
@@ -247,6 +256,7 @@ EXPORT_SYMBOL(transport_init_session);
struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
{
struct se_session *se_sess;
+ int ret;
se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
if (!se_sess) {
@@ -254,7 +264,11 @@ struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
" se_sess_cache\n");
return ERR_PTR(-ENOMEM);
}
- transport_init_session(se_sess);
+ ret = transport_init_session(se_sess);
+ if (ret < 0) {
+ kfree(se_sess);
+ return ERR_PTR(ret);
+ }
se_sess->sup_prot_ops = sup_prot_ops;
return se_sess;
@@ -581,6 +595,7 @@ void transport_free_session(struct se_session *se_sess)
sbitmap_queue_free(&se_sess->sess_tag_pool);
kvfree(se_sess->sess_cmd_map);
}
+ percpu_ref_exit(&se_sess->cmd_count);
kmem_cache_free(se_sess_cache, se_sess);
}
EXPORT_SYMBOL(transport_free_session);
@@ -2719,6 +2734,7 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
}
se_cmd->transport_state |= CMD_T_PRE_EXECUTE;
list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
+ percpu_ref_get(&se_sess->cmd_count);
out:
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
@@ -2749,8 +2765,6 @@ static void target_release_cmd_kref(struct kref *kref)
if (se_sess) {
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
list_del_init(&se_cmd->se_cmd_list);
- if (se_sess->sess_tearing_down && list_empty(&se_sess->sess_cmd_list))
- wake_up(&se_sess->cmd_list_wq);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
}
@@ -2758,6 +2772,8 @@ static void target_release_cmd_kref(struct kref *kref)
se_cmd->se_tfo->release_cmd(se_cmd);
if (compl)
complete(compl);
+
+ percpu_ref_put(&se_sess->cmd_count);
}
/**
@@ -2886,6 +2902,8 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
se_sess->sess_tearing_down = 1;
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+
+ percpu_ref_kill(&se_sess->cmd_count);
}
EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
@@ -2900,17 +2918,14 @@ void target_wait_for_sess_cmds(struct se_session *se_sess)
WARN_ON_ONCE(!se_sess->sess_tearing_down);
- spin_lock_irq(&se_sess->sess_cmd_lock);
do {
- ret = wait_event_lock_irq_timeout(
- se_sess->cmd_list_wq,
- list_empty(&se_sess->sess_cmd_list),
- se_sess->sess_cmd_lock, 180 * HZ);
+ ret = wait_event_timeout(se_sess->cmd_list_wq,
+ percpu_ref_is_zero(&se_sess->cmd_count),
+ 180 * HZ);
list_for_each_entry(cmd, &se_sess->sess_cmd_list, se_cmd_list)
target_show_cmd("session shutdown: still waiting for ",
cmd);
} while (ret <= 0);
- spin_unlock_irq(&se_sess->sess_cmd_lock);
}
EXPORT_SYMBOL(target_wait_for_sess_cmds);
diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c
index 70adcfdca8d1..124495f953fa 100644
--- a/drivers/target/target_core_xcopy.c
+++ b/drivers/target/target_core_xcopy.c
@@ -479,6 +479,8 @@ static const struct target_core_fabric_ops xcopy_pt_tfo = {
int target_xcopy_setup_pt(void)
{
+ int ret;
+
xcopy_wq = alloc_workqueue("xcopy_wq", WQ_MEM_RECLAIM, 0);
if (!xcopy_wq) {
pr_err("Unable to allocate xcopy_wq\n");
@@ -496,7 +498,9 @@ int target_xcopy_setup_pt(void)
INIT_LIST_HEAD(&xcopy_pt_nacl.acl_list);
INIT_LIST_HEAD(&xcopy_pt_nacl.acl_sess_list);
memset(&xcopy_pt_sess, 0, sizeof(struct se_session));
- transport_init_session(&xcopy_pt_sess);
+ ret = transport_init_session(&xcopy_pt_sess);
+ if (ret < 0)
+ return ret;
xcopy_pt_nacl.se_tpg = &xcopy_pt_tpg;
xcopy_pt_nacl.nacl_sess = &xcopy_pt_sess;
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index e3bdb0550a59..d9fd4eac58c2 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -601,6 +601,7 @@ struct se_session {
struct se_node_acl *se_node_acl;
struct se_portal_group *se_tpg;
void *fabric_sess_ptr;
+ struct percpu_ref cmd_count;
struct list_head sess_list;
struct list_head sess_acl_list;
struct list_head sess_cmd_list;
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index f4147b398431..eb9d0923c55c 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -116,7 +116,7 @@ struct se_session *target_setup_session(struct se_portal_group *,
struct se_session *, void *));
void target_remove_session(struct se_session *);
-void transport_init_session(struct se_session *);
+int transport_init_session(struct se_session *se_sess);
struct se_session *transport_alloc_session(enum target_prot_op);
int transport_alloc_session_tags(struct se_session *, unsigned int,
unsigned int);
--
2.19.1