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5fe23f262e
There is a race condition between ucma_close() and ucma_resolve_ip():
CPU0 CPU1
ucma_resolve_ip(): ucma_close():
ctx = ucma_get_ctx(file, cmd.id);
list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) {
mutex_lock(&mut);
idr_remove(&ctx_idr, ctx->id);
mutex_unlock(&mut);
...
mutex_lock(&mut);
if (!ctx->closing) {
mutex_unlock(&mut);
rdma_destroy_id(ctx->cm_id);
...
ucma_free_ctx(ctx);
ret = rdma_resolve_addr();
ucma_put_ctx(ctx);
Before idr_remove(), ucma_get_ctx() could still find the ctx
and after rdma_destroy_id(), rdma_resolve_addr() may still
access id_priv pointer. Also, ucma_put_ctx() may use ctx after
ucma_free_ctx() too.
ucma_close() should call ucma_put_ctx() too which tests the
refcnt and waits for the last one releasing it. The similar
pattern is already used by ucma_destroy_id().
Reported-and-tested-by: syzbot+da2591e115d57a9cbb8b@syzkaller.appspotmail.com
Reported-by: syzbot+cfe3c1e8ef634ba8964b@syzkaller.appspotmail.com
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.