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Date: Tue, 14 Sep 2021 16:54:44 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Tao Liu <thomas.liu@...oud.cn>
Cc: dledford@...hat.com, leon@...nel.org, haakon.bugge@...cle.com,
shayd@...dia.com, avihaih@...dia.com, linux-rdma@...r.kernel.org,
linux-kernel@...r.kernel.org, thomas.liu@...oud.com
Subject: Re: [PATCH] RDMA/cma: Fix listener leak in rdma_cma_listen_on_all()
failure
On Mon, Sep 13, 2021 at 05:33:44PM +0800, Tao Liu wrote:
> rdma_cma_listen_on_all() just destroy listener which lead to an error,
> but not including those already added in listen_list. Then cm state
> fallbacks to RDMA_CM_ADDR_BOUND.
>
> When user destroys id, the listeners will not be destroyed, and
> process stucks.
>
> task:rping state:D stack: 0 pid:19605 ppid: 47036 flags:0x00000084
> Call Trace:
> __schedule+0x29a/0x780
> ? free_unref_page_commit+0x9b/0x110
> schedule+0x3c/0xa0
> schedule_timeout+0x215/0x2b0
> ? __flush_work+0x19e/0x1e0
> wait_for_completion+0x8d/0xf0
> _destroy_id+0x144/0x210 [rdma_cm]
> ucma_close_id+0x2b/0x40 [rdma_ucm]
> __destroy_id+0x93/0x2c0 [rdma_ucm]
> ? __xa_erase+0x4a/0xa0
> ucma_destroy_id+0x9a/0x120 [rdma_ucm]
> ucma_write+0xb8/0x130 [rdma_ucm]
> vfs_write+0xb4/0x250
> ksys_write+0xb5/0xd0
> ? syscall_trace_enter.isra.19+0x123/0x190
> do_syscall_64+0x33/0x40
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Fixes: c80a0c52d85c ("RDMA/cma: Add missing error handling of listen_id")
> Signed-off-by: Tao Liu <thomas.liu@...oud.cn>
> Reviewed-by: Leon Romanovsky <leonro@...dia.com>
> drivers/infiniband/core/cma.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
I'd like to see a bit more than this, I reworked the patch slightly
into this below. It is in for-rc so let me know if it busted up. Thanks
>From a17a1faf5d3e2e19a75397dfd740dbde06f054c3 Mon Sep 17 00:00:00 2001
From: Tao Liu <thomas.liu@...oud.cn>
Date: Mon, 13 Sep 2021 17:33:44 +0800
Subject: [PATCH] RDMA/cma: Fix listener leak in rdma_cma_listen_on_all()
failure
If cma_listen_on_all() fails it leaves the per-device ID still on the
listen_list but the state is not set to RDMA_CM_ADDR_BOUND.
When the cmid is eventually destroyed cma_cancel_listens() is not called
due to the wrong state, however the per-device IDs are still holding the
refcount preventing the ID from being destroyed, thus deadlocking:
task:rping state:D stack: 0 pid:19605 ppid: 47036 flags:0x00000084
Call Trace:
__schedule+0x29a/0x780
? free_unref_page_commit+0x9b/0x110
schedule+0x3c/0xa0
schedule_timeout+0x215/0x2b0
? __flush_work+0x19e/0x1e0
wait_for_completion+0x8d/0xf0
_destroy_id+0x144/0x210 [rdma_cm]
ucma_close_id+0x2b/0x40 [rdma_ucm]
__destroy_id+0x93/0x2c0 [rdma_ucm]
? __xa_erase+0x4a/0xa0
ucma_destroy_id+0x9a/0x120 [rdma_ucm]
ucma_write+0xb8/0x130 [rdma_ucm]
vfs_write+0xb4/0x250
ksys_write+0xb5/0xd0
? syscall_trace_enter.isra.19+0x123/0x190
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Ensure that cma_listen_on_all() atomically unwinds its action under the
lock during error and reorganize how destroy_id works to be directly
sensitive to the listen list not indirectly through the state and some
other random collection of variables.
Fixes: c80a0c52d85c ("RDMA/cma: Add missing error handling of listen_id")
Link: https://lore.kernel.org/r/20210913093344.17230-1-thomas.liu@ucloud.cn
Signed-off-by: Tao Liu <thomas.liu@...oud.cn>
Reviewed-by: Leon Romanovsky <leonro@...dia.com>
Signed-off-by: Jason Gunthorpe <jgg@...dia.com>
---
drivers/infiniband/core/cma.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 86ee3b01b3ee47..be6beee1dd4c5e 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -1746,16 +1746,17 @@ static void cma_cancel_route(struct rdma_id_private *id_priv)
}
}
-static void cma_cancel_listens(struct rdma_id_private *id_priv)
+static void _cma_cancel_listens(struct rdma_id_private *id_priv)
{
struct rdma_id_private *dev_id_priv;
+ lockdep_assert_held(&lock);
+
/*
* Remove from listen_any_list to prevent added devices from spawning
* additional listen requests.
*/
- mutex_lock(&lock);
- list_del(&id_priv->list);
+ list_del_init(&id_priv->list);
while (!list_empty(&id_priv->listen_list)) {
dev_id_priv = list_entry(id_priv->listen_list.next,
@@ -1768,6 +1769,20 @@ static void cma_cancel_listens(struct rdma_id_private *id_priv)
rdma_destroy_id(&dev_id_priv->id);
mutex_lock(&lock);
}
+}
+
+static void cma_cancel_listens(struct rdma_id_private *id_priv)
+{
+ /*
+ * During _destroy_id() it is not possible for this value to transition
+ * from empty to !empty, test it outside to lock to avoid taking a
+ * global lock on every destroy. Only listen all cases will have
+ * something to do
+ */
+ if (list_empty(&id_priv->list))
+ return;
+ mutex_lock(&lock);
+ _cma_cancel_listens(id_priv);
mutex_unlock(&lock);
}
@@ -1781,10 +1796,6 @@ static void cma_cancel_operation(struct rdma_id_private *id_priv,
case RDMA_CM_ROUTE_QUERY:
cma_cancel_route(id_priv);
break;
- case RDMA_CM_LISTEN:
- if (cma_any_addr(cma_src_addr(id_priv)) && !id_priv->cma_dev)
- cma_cancel_listens(id_priv);
- break;
default:
break;
}
@@ -1855,6 +1866,7 @@ static void cma_leave_mc_groups(struct rdma_id_private *id_priv)
static void _destroy_id(struct rdma_id_private *id_priv,
enum rdma_cm_state state)
{
+ cma_cancel_listens(id_priv);
cma_cancel_operation(id_priv, state);
rdma_restrack_del(&id_priv->res);
@@ -2579,7 +2591,7 @@ static int cma_listen_on_all(struct rdma_id_private *id_priv)
return 0;
err_listen:
- list_del(&id_priv->list);
+ _cma_cancel_listens(id_priv);
mutex_unlock(&lock);
if (to_destroy)
rdma_destroy_id(&to_destroy->id);
--
2.33.0
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