This is a note to let you know that I've just added the patch titled
RDMA/ucma: Fix locking for ctx->events_reported
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rdma-ucma-fix-locking-for-ctx-events_reported.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit de8a786a08ae3efd94e198a201ad8f3574fdc934
Author: Jason Gunthorpe <jgg@xxxxxxxxxx>
Date: Tue Aug 18 15:05:21 2020 +0300
RDMA/ucma: Fix locking for ctx->events_reported
[ 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@xxxxxxxxxx
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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;
}
