4.20-stable review patch. If anyone has any objections, please let me know.
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[ 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@linux-iscsi.org Cc: Mike Christie mchristi@redhat.com Cc: Christoph Hellwig hch@lst.de Cc: David Disseldorp ddiss@suse.de Cc: Hannes Reinecke hare@suse.de Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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);