Add timeout to cm_destroy_id, so that userspace can trigger any data
collection that would help in analyzing the cause of delay in destroying
the cm_id.
New noinline function helps dtrace/ebpf programs to hook on to it.
Existing functionality isn't changed except triggering a probe-able new
function at every timeout interval.
We have seen cases where CM messages stuck with MAD layer (either due to
software bug or faulty HCA), leading to cm_id getting stuck in the
following call stack. This patch helps in resolving such issues faster.
kernel: ... INFO: task XXXX:56778 blocked for more than 120 seconds.
..
Call Trace:
__schedule+0x2bc/0x895
schedule+0x36/0x7c
schedule_timeout+0x1f6/0x31f
? __slab_free+0x19c/0x2ba
wait_for_completion+0x12b/0x18a
? wake_up_q+0x80/0x73
cm_destroy_id+0x345/0x610 [ib_cm]
ib_destroy_cm_id+0x10/0x20 [ib_cm]
rdma_destroy_id+0xa8/0x300 [rdma_cm]
ucma_destroy_id+0x13e/0x190 [rdma_ucm]
ucma_write+0xe0/0x160 [rdma_ucm]
__vfs_write+0x3a/0x16d
vfs_write+0xb2/0x1a1
? syscall_trace_enter+0x1ce/0x2b8
SyS_write+0x5c/0xd3
do_syscall_64+0x79/0x1b9
entry_SYSCALL_64_after_hwframe+0x16d/0x0
Orabug: 36280065
Signed-off-by: Manjunath Patil <[email protected]>
---
drivers/infiniband/core/cm.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index ff58058aeadc..00a16b08c7e2 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -34,6 +34,7 @@ MODULE_AUTHOR("Sean Hefty");
MODULE_DESCRIPTION("InfiniBand CM");
MODULE_LICENSE("Dual BSD/GPL");
+static unsigned long cm_destroy_id_wait_timeout_sec = 10;
static const char * const ibcm_rej_reason_strs[] = {
[IB_CM_REJ_NO_QP] = "no QP",
[IB_CM_REJ_NO_EEC] = "no EEC",
@@ -1025,10 +1026,20 @@ static void cm_reset_to_idle(struct cm_id_private *cm_id_priv)
}
}
+static noinline void cm_destroy_id_wait_timeout(struct ib_cm_id *cm_id)
+{
+ struct cm_id_private *cm_id_priv;
+
+ cm_id_priv = container_of(cm_id, struct cm_id_private, id);
+ pr_err("%s: cm_id=%p timed out. state=%d refcnt=%d\n", __func__,
+ cm_id, cm_id->state, refcount_read(&cm_id_priv->refcount));
+}
+
static void cm_destroy_id(struct ib_cm_id *cm_id, int err)
{
struct cm_id_private *cm_id_priv;
struct cm_work *work;
+ int ret;
cm_id_priv = container_of(cm_id, struct cm_id_private, id);
spin_lock_irq(&cm_id_priv->lock);
@@ -1135,7 +1146,14 @@ static void cm_destroy_id(struct ib_cm_id *cm_id, int err)
xa_erase(&cm.local_id_table, cm_local_id(cm_id->local_id));
cm_deref_id(cm_id_priv);
- wait_for_completion(&cm_id_priv->comp);
+ do {
+ ret = wait_for_completion_timeout(&cm_id_priv->comp,
+ msecs_to_jiffies(
+ cm_destroy_id_wait_timeout_sec * 1000));
+ if (!ret) /* timeout happened */
+ cm_destroy_id_wait_timeout(cm_id);
+ } while (!ret);
+
while ((work = cm_dequeue_work(cm_id_priv)) != NULL)
cm_free_work(work);
--
2.31.1
On Thu, Mar 07, 2024 at 04:55:53PM -0800, Manjunath Patil wrote:
> Add timeout to cm_destroy_id, so that userspace can trigger any data
> collection that would help in analyzing the cause of delay in destroying
> the cm_id.
>
> New noinline function helps dtrace/ebpf programs to hook on to it.
> Existing functionality isn't changed except triggering a probe-able new
> function at every timeout interval.
>
> We have seen cases where CM messages stuck with MAD layer (either due to
> software bug or faulty HCA), leading to cm_id getting stuck in the
> following call stack. This patch helps in resolving such issues faster.
>
> kernel: ... INFO: task XXXX:56778 blocked for more than 120 seconds.
> ...
> Call Trace:
> __schedule+0x2bc/0x895
> schedule+0x36/0x7c
> schedule_timeout+0x1f6/0x31f
> ? __slab_free+0x19c/0x2ba
> wait_for_completion+0x12b/0x18a
> ? wake_up_q+0x80/0x73
> cm_destroy_id+0x345/0x610 [ib_cm]
> ib_destroy_cm_id+0x10/0x20 [ib_cm]
> rdma_destroy_id+0xa8/0x300 [rdma_cm]
> ucma_destroy_id+0x13e/0x190 [rdma_ucm]
> ucma_write+0xe0/0x160 [rdma_ucm]
> __vfs_write+0x3a/0x16d
> vfs_write+0xb2/0x1a1
> ? syscall_trace_enter+0x1ce/0x2b8
> SyS_write+0x5c/0xd3
> do_syscall_64+0x79/0x1b9
> entry_SYSCALL_64_after_hwframe+0x16d/0x0
>
> Orabug: 36280065
>
> Signed-off-by: Manjunath Patil <[email protected]>
> ---
> drivers/infiniband/core/cm.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> index ff58058aeadc..00a16b08c7e2 100644
> --- a/drivers/infiniband/core/cm.c
> +++ b/drivers/infiniband/core/cm.c
> @@ -34,6 +34,7 @@ MODULE_AUTHOR("Sean Hefty");
> MODULE_DESCRIPTION("InfiniBand CM");
> MODULE_LICENSE("Dual BSD/GPL");
>
> +static unsigned long cm_destroy_id_wait_timeout_sec = 10;
Don't need this to be a variable, just make it a #define
> static const char * const ibcm_rej_reason_strs[] = {
> [IB_CM_REJ_NO_QP] = "no QP",
> [IB_CM_REJ_NO_EEC] = "no EEC",
> @@ -1025,10 +1026,20 @@ static void cm_reset_to_idle(struct cm_id_private *cm_id_priv)
> }
> }
>
> +static noinline void cm_destroy_id_wait_timeout(struct ib_cm_id *cm_id)
> +{
> + struct cm_id_private *cm_id_priv;
> +
> + cm_id_priv = container_of(cm_id, struct cm_id_private, id);
> + pr_err("%s: cm_id=%p timed out. state=%d refcnt=%d\n", __func__,
> + cm_id, cm_id->state, refcount_read(&cm_id_priv->refcount));
> +}
WARN_ON? Is the backtrace valuable?
Jason
On 3/8/24 6:18 AM, Jason Gunthorpe wrote:
> On Thu, Mar 07, 2024 at 04:55:53PM -0800, Manjunath Patil wrote:
>> Add timeout to cm_destroy_id, so that userspace can trigger any data
>> collection that would help in analyzing the cause of delay in destroying
>> the cm_id.
>>
>> New noinline function helps dtrace/ebpf programs to hook on to it.
>> Existing functionality isn't changed except triggering a probe-able new
>> function at every timeout interval.
>>
>> We have seen cases where CM messages stuck with MAD layer (either due to
>> software bug or faulty HCA), leading to cm_id getting stuck in the
>> following call stack. This patch helps in resolving such issues faster.
>>
>> kernel: ... INFO: task XXXX:56778 blocked for more than 120 seconds.
>> ...
>> Call Trace:
>> __schedule+0x2bc/0x895
>> schedule+0x36/0x7c
>> schedule_timeout+0x1f6/0x31f
>> ? __slab_free+0x19c/0x2ba
>> wait_for_completion+0x12b/0x18a
>> ? wake_up_q+0x80/0x73
>> cm_destroy_id+0x345/0x610 [ib_cm]
>> ib_destroy_cm_id+0x10/0x20 [ib_cm]
>> rdma_destroy_id+0xa8/0x300 [rdma_cm]
>> ucma_destroy_id+0x13e/0x190 [rdma_ucm]
>> ucma_write+0xe0/0x160 [rdma_ucm]
>> __vfs_write+0x3a/0x16d
>> vfs_write+0xb2/0x1a1
>> ? syscall_trace_enter+0x1ce/0x2b8
>> SyS_write+0x5c/0xd3
>> do_syscall_64+0x79/0x1b9
>> entry_SYSCALL_64_after_hwframe+0x16d/0x0
>>
>> Orabug: 36280065
>>
>> Signed-off-by: Manjunath Patil <[email protected]>
>> ---
>> drivers/infiniband/core/cm.c | 20 +++++++++++++++++++-
>> 1 file changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
>> index ff58058aeadc..00a16b08c7e2 100644
>> --- a/drivers/infiniband/core/cm.c
>> +++ b/drivers/infiniband/core/cm.c
>> @@ -34,6 +34,7 @@ MODULE_AUTHOR("Sean Hefty");
>> MODULE_DESCRIPTION("InfiniBand CM");
>> MODULE_LICENSE("Dual BSD/GPL");
>>
>> +static unsigned long cm_destroy_id_wait_timeout_sec = 10;
>
> Don't need this to be a variable, just make it a #define
sure. I will send v3 with this change.
>
>> static const char * const ibcm_rej_reason_strs[] = {
>> [IB_CM_REJ_NO_QP] = "no QP",
>> [IB_CM_REJ_NO_EEC] = "no EEC",
>> @@ -1025,10 +1026,20 @@ static void cm_reset_to_idle(struct cm_id_private *cm_id_priv)
>> }
>> }
>>
>> +static noinline void cm_destroy_id_wait_timeout(struct ib_cm_id *cm_id)
>> +{
>> + struct cm_id_private *cm_id_priv;
>> +
>> + cm_id_priv = container_of(cm_id, struct cm_id_private, id);
>> + pr_err("%s: cm_id=%p timed out. state=%d refcnt=%d\n", __func__,
>> + cm_id, cm_id->state, refcount_read(&cm_id_priv->refcount));
>> +}
>
> WARN_ON? Is the backtrace valuable?
No. I would prefer just pr_err to avoid noise if there are multiple cm_ids are stuck due to any lower layer issue.
Thank you for your feedback.
-Manjunath
>
> Jason