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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 <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2020-08-18 15:05:20 +03:00
parent 308571debc
commit 09e328e47a
1 changed files with 5 additions and 1 deletions
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6
drivers/infiniband/core/ucma.c
View File

@ -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);