Re: panic with CONFIG_FAIL_MMC_REQUEST and cqhci

From: Ritesh Harjani
Date: Fri Feb 22 2019 - 08:42:24 EST


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.

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