6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Neill Kapron [ Upstream commit e78dcb1f7ec271449c54984dc90c62a5ba272de7 ] In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`. If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer. To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window. We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers. Fixes: de2080d41b5d ("gadget/function/f_fs.c: close leaks") Cc: stable@vger.kernel.org Reported-by: Xingyu Jin Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260724235100.106011-1-nkapron@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1261,8 +1261,10 @@ static ssize_t ffs_epfile_write_iter(str if (res == -EIOCBQUEUED) return res; if (p->aio) { + kiocb->ki_complete(kiocb, res); mmdrop(p->mm); kfree(p); + return -EIOCBQUEUED; } else { *from = p->data; } @@ -1310,9 +1312,11 @@ static ssize_t ffs_epfile_read_iter(stru return res; if (p->aio) { + kiocb->ki_complete(kiocb, res); mmdrop(p->mm); kfree(p->to_free); kfree(p); + return -EIOCBQUEUED; } else { *to = p->data; }