Re: [PATCH] block: blk_init_allocated_queue() set q->fq as NULL in the fail case

[Jens Axboe]

On 7/30/18 12:11 AM, xiao jin wrote:
> We find the memory use-after-free issue in __blk_drain_queue()
> on the kernel 4.14. After read the latest kernel 4.18-rc6 we
> think it has the same problem.
> 
> Memory is allocated for q->fq in the blk_init_allocated_queue().
> If the elevator init function called with error return, it will
> run into the fail case to free the q->fq.
> 
> Then the __blk_drain_queue() uses the same memory after the free
> of the q->fq, it will lead to the unpredictable event.
> 
> The patch is to set q->fq as NULL in the fail case of
> blk_init_allocated_queue().

Applied, thanks.

-- 
Jens Axboe