On 2024/4/17 1:13, Bart Van Assche wrote:
> If ufshcd_abort() returns SUCCESS for an already completed command then
> that command is completed twice. This results in a crash. Prevent this by
> checking whether a command has completed without completion interrupt from
> the timeout handler. This CL fixes the following kernel crash:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> Call trace:
> dma_direct_map_sg+0x70/0x274
> scsi_dma_map+0x84/0x124
> ufshcd_queuecommand+0x3fc/0x880
> scsi_queue_rq+0x7d0/0x111c
> blk_mq_dispatch_rq_list+0x440/0xebc
> blk_mq_do_dispatch_sched+0x5a4/0x6b8
> __blk_mq_sched_dispatch_requests+0x150/0x220
> __blk_mq_run_hw_queue+0xf0/0x218
> __blk_mq_delay_run_hw_queue+0x8c/0x18c
> blk_mq_run_hw_queue+0x1a4/0x360
> blk_mq_sched_insert_requests+0x130/0x334
> blk_mq_flush_plug_list+0x138/0x234
> blk_flush_plug_list+0x118/0x164
> blk_finish_plug()
> read_pages+0x38c/0x408
> page_cache_ra_unbounded+0x230/0x2f8
> do_sync_mmap_readahead+0x1a4/0x208
> filemap_fault+0x27c/0x8f4
> f2fs_filemap_fault+0x28/0xfc
> __do_fault+0xc4/0x208
> handle_pte_fault+0x290/0xe04
> do_handle_mm_fault+0x52c/0x858
> do_page_fault+0x5dc/0x798
> do_translation_fault+0x40/0x54
> do_mem_abort+0x60/0x134
> el0_da+0x40/0xb8
> el0t_64_sync_handler+0xc4/0xe4
> el0t_64_sync+0x1b4/0x1b8
>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> drivers/ufs/core/ufshcd.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index c552bf391f79..c44515605031 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -8880,6 +8880,25 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
> static enum scsi_timeout_action ufshcd_eh_timed_out(struct scsi_cmnd *scmd)
> {
> struct ufs_hba *hba = shost_priv(scmd->device->host);
> + struct scsi_cmnd *cmd2 = scmd;
> +
> + WARN_ON_ONCE(!scmd);
> +
> + if (is_mcq_enabled(hba)) {
> + struct request *rq = scsi_cmd_to_rq(scmd);
> + struct ufs_hw_queue *hwq = ufshcd_mcq_req_to_hwq(hba, rq);
> +
> + ufshcd_mcq_poll_cqe_lock(hba, hwq, &cmd2);
> + } else {
> + __ufshcd_poll(hba->host, UFSHCD_POLL_FROM_INTERRUPT_CONTEXT,
> + &cmd2);
> + }
> + if (cmd2 == NULL) {
> + sdev_printk(KERN_INFO, scmd->device,
> + "%s: cmd with tag %#x has already been completed\n",
> + __func__, blk_mq_unique_tag(scsi_cmd_to_rq(scmd)));
Would here cause a UAF because the scsi_cmnd has already been completed?
If UAF would not happen, I think maybe scmd_printk() would be better than sdev_printk()
> + return SCSI_EH_DONE;
> + }
>
> if (!hba->system_suspending) {
> /* Activate the error handler in the SCSI core. */
>
