[PATCH v2] infiniband: remove WARN that is not kernel bug

[Dmitry Vyukov]

WARNINGs mean kernel bugs.
The one in ucma_write() points to user programming error
or a malicious attempt. This is not a kernel bug, remove it.

BUG/WARNs that are not kernel bugs hinder automated testing effots.

Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Doug Ledford <dledford@xxxxxxxxxx>
Cc: Sean Hefty <sean.hefty@xxxxxxxxx>
Cc: Hal Rosenstock <hal.rosenstock@xxxxxxxxx>
Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Cc: linux-rdma@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: syzkaller@xxxxxxxxxxxxxxxx

---
Changes since v1:
 - added printk_once
---
 drivers/infiniband/core/ucma.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 9520154..405d0ce 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1584,8 +1584,11 @@ static ssize_t ucma_write(struct file *filp, const char __user *buf,
 	struct rdma_ucm_cmd_hdr hdr;
 	ssize_t ret;
 
-	if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+	if (!ib_safe_file_access(filp)) {
+		printk_once("ucma_write: process %d (%s) tried to do something hinky\n",
+			task_tgid_vnr(current), current->comm);
 		return -EACCES;
+	}
 
 	if (len < sizeof(hdr))
 		return -EINVAL;
-- 
2.8.0.rc3.226.g39d4020