diff mbox series

[4.19,133/264] RDMA/ucma: Fix locking for ctx->events_reported

Message ID 20201027135436.933086906@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Oct. 27, 2020, 1:53 p.m. UTC 
From: Jason Gunthorpe <jgg@nvidia.com>

[ Upstream commit 98837c6c3d7285f6eca86480b6f7fac6880e27a8 ]

This value is locked under the file->mut, ensure it is held whenever
touching it.

The case in ucma_migrate_id() is a race, while in ucma_free_uctx() it is
already not possible for the write side to run, the movement is just for
clarity.

Fixes: 88314e4dda1e ("RDMA/cma: add support for rdma_migrate_id()")
Link: https://lore.kernel.org/r/20200818120526.702120-10-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/core/ucma.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 2acc30c3d5b2d..0c095c8c0ac5b 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -588,6 +588,7 @@  static int ucma_free_ctx(struct ucma_context *ctx)
 			list_move_tail(&uevent->list, &list);
 	}
 	list_del(&ctx->list);
+	events_reported = ctx->events_reported;
 	mutex_unlock(&ctx->file->mut);
 
 	list_for_each_entry_safe(uevent, tmp, &list, list) {
@@ -597,7 +598,6 @@  static int ucma_free_ctx(struct ucma_context *ctx)
 		kfree(uevent);
 	}
 
-	events_reported = ctx->events_reported;
 	mutex_destroy(&ctx->mutex);
 	kfree(ctx);
 	return events_reported;
@@ -1644,7 +1644,9 @@  static ssize_t ucma_migrate_id(struct ucma_file *new_file,
 
 	cur_file = ctx->file;
 	if (cur_file == new_file) {
+		mutex_lock(&cur_file->mut);
 		resp.events_reported = ctx->events_reported;
+		mutex_unlock(&cur_file->mut);
 		goto response;
 	}