From: Wesley Cheng wcheng@codeaurora.org

stable inclusion from stable-v5.10.44 commit 5cead896962d8b25dee8a8efc85b076572732b86 bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=406 CVE: NA

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commit 6fc1db5e6211e30fbb1cee8d7925d79d4ed2ae14 upstream.

During unbind, ffs_func_eps_disable() will be executed, resulting in completion callbacks for any pending USB requests. When using AIO, irrespective of the completion status, io_data work is queued to io_completion_wq to evaluate and handle the completed requests. Since work runs asynchronously to the unbind() routine, there can be a scenario where the work runs after the USB gadget has been fully removed, resulting in accessing of a resource which has been already freed. (i.e. usb_ep_free_request() accessing the USB ep structure)

Explicitly drain the io_completion_wq, instead of relying on the destroy_workqueue() (in ffs_data_put()) to make sure no pending completion work items are running.

Signed-off-by: Wesley Cheng wcheng@codeaurora.org Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/1621644261-1236-1-git-send-email-wcheng@codeaurora... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: liuhao qq1107732331@qq.com --- drivers/usb/gadget/function/f_fs.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index ffe67d836b0c..7df180b110af 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -3566,6 +3566,9 @@ static void ffs_func_unbind(struct usb_configuration *c, ffs->func = NULL; }

+ /* Drain any pending AIO completions */ + drain_workqueue(ffs->io_completion_wq); + if (!--opts->refcnt) functionfs_unbind(ffs);