Comment 17 for bug 1823836

------- Comment From <email address hidden> 2019-04-18 17:51 EDT-------
(In reply to comment #27)

Thanks for the tips Christian, I was able to isolated the fix to commit d38817ea

---
From d38817ea554a9fd140e56414a7c74e7eef444c50 Mon Sep 17 00:00:00 2001
From: Mark Bloch <email address hidden>
Date: Wed, 20 Feb 2019 20:00:45 +0000
Subject: [PATCH] verbs: clear cmd buffer when creating indirection table

[ Upstream commit 34225464c1d165f63ffd462364810cc9f374109d ]

Make sure we clear the cmd buffer, not doing so will make the kernel to
fail the command.

Fixes: 75c65bbcadcd ("verbs: Consolidate duplicate code in create_rwq_ind_table")
Signed-off-by: Mark Bloch <email address hidden>
Signed-off-by: Yishai Hadas <email address hidden>
Signed-off-by: Nicolas Morey-Chaisemartin <email address hidden>
---
libibverbs/cmd.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/libibverbs/cmd.c b/libibverbs/cmd.c
index 34c71e56..5817c598 100644
--- a/libibverbs/cmd.c
+++ b/libibverbs/cmd.c
@@ -1854,6 +1854,7 @@ int ibv_cmd_create_rwq_ind_table(struct ibv_context *context,
cmd_size = sizeof(*cmd) + num_tbl_entries * sizeof(cmd->wq_handles[0]);
cmd_size = (cmd_size + 7) / 8 * 8;
cmd = alloca(cmd_size);
+ memset(cmd, 0, cmd_size);

for (i = 0; i < num_tbl_entries; i++)
cmd->wq_handles[i] = init_attr->ind_tbl[i]->handle;
--
2.20.1

This change makes sense based on my debug.

I also applied the change to the head of debian/master branch and verified it works as well.

This should not be a Power specific bug, We just got lucky on x86_64, cmd must have already zeroed.