The Linux kernel's fastrpc driver had a concurrency vulnerability where, if an invoke operation was interrupted by a signal, the function fastrpc_internal_invoke() moved buffers from fl->mmaps to cctx->invoke_interrupted_mmaps without holding the fl->lock. This lock is normally used to serialize access to fl->mmaps in other functions like fastrpc_req_mmap() and fastrpc_req_munmap(). The absence of this lock during the move operation could lead to race conditions or data corruption. The fix involved taking the fl->lock around the move operation to match the locking discipline used elsewhere.

The vulnerability could lead to race conditions or inconsistent state in the fastrpc memory map management when an invoke is interrupted by a signal. This may cause instability or unexpected behavior in the kernel's fastrpc subsystem. No direct exploitation or impact details are provided.

A fix has been applied to the Linux kernel to take the fl->lock when moving mmaps on interrupted invoke operations. Users should update to a kernel version that includes this fix. Patch status is not explicitly confirmed in the provided data; check the vendor or Linux kernel advisories for the exact fixed versions and update accordingly.