Re: [PATCH v2] block, bfq: fix possible uaf for 'bfqq->bic'

[Jens Axboe]

On Wed, 14 Dec 2022 11:04:30 +0800, Yu Kuai wrote:
> Our test report a uaf for 'bfqq->bic' in 5.10:
> 
> ==================================================================
> BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30
> 
> CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014
> Call Trace:
>  bfq_select_queue+0x378/0xa30
>  bfq_dispatch_request+0xe8/0x130
>  blk_mq_do_dispatch_sched+0x62/0xb0
>  __blk_mq_sched_dispatch_requests+0x215/0x2a0
>  blk_mq_sched_dispatch_requests+0x8f/0xd0
>  __blk_mq_run_hw_queue+0x98/0x180
>  __blk_mq_delay_run_hw_queue+0x22b/0x240
>  blk_mq_run_hw_queue+0xe3/0x190
>  blk_mq_sched_insert_requests+0x107/0x200
>  blk_mq_flush_plug_list+0x26e/0x3c0
>  blk_finish_plug+0x63/0x90
>  __iomap_dio_rw+0x7b5/0x910
>  iomap_dio_rw+0x36/0x80
>  ext4_dio_read_iter+0x146/0x190 [ext4]
>  ext4_file_read_iter+0x1e2/0x230 [ext4]
>  new_sync_read+0x29f/0x400
>  vfs_read+0x24e/0x2d0
>  ksys_read+0xd5/0x1b0
>  do_syscall_64+0x33/0x40
>  entry_SYSCALL_64_after_hwframe+0x61/0xc6
> 
> [...]

Applied, thanks!

[1/1] block, bfq: fix possible uaf for 'bfqq->bic'
      commit: 64dc8c732f5c2b406cc752e6aaa1bd5471159cab

Best regards,
-- 
Jens Axboe