Re: panic with CONFIG_FAIL_MMC_REQUEST and cqhci

[Laura Abbott]

On 2/22/19 5:42 AM, Ritesh Harjani wrote:
> Hi Laura,
>
> On 2/19/2019 12:59 AM, Laura Abbott wrote:
> > Hi,
> >
> > Fedora got report of a panic when I accidentally left debugging enabled
> > on a build https://bugzilla.redhat.com/show_bug.cgi?id=1677438
> >
> > It looks like a panic from code in CONFIG_FAIL_MMC_REQUEST from the
> > cqhci driver because there isn't a command (high level overview)
>
> With CQHCI, in case of non-DCMD (data) requests, mrq->cmd can be NULL.
> Is this crash happening always (100% on bootup) with CQHCI & CONFIG_FAIL_MMC_REQUEST enabled?
>
> Sure, I will role out a patch to handle this case.
> It will be great, if you could also confirm it from your side.

Thanks, I'll have to follow up with the reporter and see if he
gets back to me.

> Regards
> Ritesh
>
>
> > (gdb) list *(mmc_should_fail_request+0xa)
> > 0x149a is in mmc_should_fail_request (drivers/mmc/core/core.c:98).
> > 93ÂÂÂÂÂÂÂ };
> > 94
> > 95ÂÂÂÂÂÂÂ if (!data)
> > 96ÂÂÂÂÂÂÂÂÂÂÂ return;
> > 97
> > 98ÂÂÂÂÂÂÂ if (cmd->error || data->error ||
> > 99ÂÂÂÂÂÂÂÂÂÂÂ !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
> > 100ÂÂÂÂÂÂÂÂÂÂÂ return;
> > 101
> > 102ÂÂÂÂÂÂÂ data->error = data_errors[prandom_u32() % ARRAY_SIZE(data_errors)];
> > (gdb)
> >
> > (gdb) list *(mmc_cqe_request_done+0x1c)
> > 0x2a6c is in mmc_cqe_request_done (drivers/mmc/core/core.c:505).
> > 500ÂÂÂ void mmc_cqe_request_done(struct mmc_host *host, struct mmc_request *mrq)
> > 501ÂÂÂ {
> > 502ÂÂÂÂÂÂÂ mmc_should_fail_request(host, mrq);
> > 503
> > 504ÂÂÂÂÂÂÂ /* Flag re-tuning needed on CRC errors */
> > 505ÂÂÂÂÂÂÂ if ((mrq->cmd && mrq->cmd->error == -EILSEQ) ||
> > 506ÂÂÂÂÂÂÂÂÂÂÂ (mrq->data && mrq->data->error == -EILSEQ))
> > 507ÂÂÂÂÂÂÂÂÂÂÂ mmc_retune_needed(host);
> > 508
> > 509ÂÂÂÂÂÂÂ trace_mmc_request_done(host, mrq);
> >
> >
> > (gdb) list *(cqhci_irq+0x1d2)
> > 0x1172 is in cqhci_irq (drivers/mmc/host/cqhci.c:747).
> > 742ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ data->bytes_xfered = 0;
> > 743ÂÂÂÂÂÂÂÂÂÂÂ else
> > 744ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ data->bytes_xfered = data->blksz * data->blocks;
> > 745ÂÂÂÂÂÂÂ }
> > 746
> > 747ÂÂÂÂÂÂÂ mmc_cqe_request_done(mmc, mrq);
> > 748ÂÂÂ }
> > 749
> > 750ÂÂÂ irqreturn_t cqhci_irq(struct mmc_host *mmc, u32 intmask, int cmd_error,
> > 751ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int data_error)
> >
> > This can be worked around by turning off the option but it
> > seems like something to fix up.
> >
> > Thanks,
> > Laura