From 09e328e47a695b0d346598f5d6593ee598e64885 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Tue, 18 Aug 2020 15:05:20 +0300 Subject: [PATCH] RDMA/ucma: Fix the locking of ctx->file ctx->file is changed under the file->mut lock by ucma_migrate_id(), which is impossible to lock correctly. Instead change ctx->file under the handler_lock and ctx_table lock and revise all places touching ctx->file to use this locking when reading ctx->file. Link: https://lore.kernel.org/r/20200818120526.702120-9-leon@kernel.org Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/ucma.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c index 18285941aec3..f7ec71225e87 100644 --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -547,6 +547,7 @@ static void ucma_cleanup_mc_events(struct ucma_multicast *mc) { struct ucma_event *uevent, *tmp; + rdma_lock_handler(mc->ctx->cm_id); mutex_lock(&mc->ctx->file->mut); list_for_each_entry_safe(uevent, tmp, &mc->ctx->file->event_list, list) { if (uevent->mc != mc) @@ -556,6 +557,7 @@ static void ucma_cleanup_mc_events(struct ucma_multicast *mc) kfree(uevent); } mutex_unlock(&mc->ctx->file->mut); + rdma_unlock_handler(mc->ctx->cm_id); } /* @@ -1600,7 +1602,7 @@ static ssize_t ucma_leave_multicast(struct ucma_file *file, mc = xa_load(&multicast_table, cmd.id); if (!mc) mc = ERR_PTR(-ENOENT); - else if (mc->ctx->file != file) + else if (READ_ONCE(mc->ctx->file) != file) mc = ERR_PTR(-EINVAL); else if (!refcount_inc_not_zero(&mc->ctx->ref)) mc = ERR_PTR(-ENXIO); @@ -1692,6 +1694,7 @@ static ssize_t ucma_migrate_id(struct ucma_file *new_file, goto file_put; } + rdma_lock_handler(ctx->cm_id); cur_file = ctx->file; if (cur_file == new_file) { resp.events_reported = ctx->events_reported; @@ -1718,6 +1721,7 @@ response: &resp, sizeof(resp))) ret = -EFAULT; + rdma_unlock_handler(ctx->cm_id); ucma_put_ctx(ctx); file_put: fdput(f); -- 2.11.0