Hi Evgeniy
On 02/21/2018 09:57 AM, Evgeniy Didin wrote:
> In commit 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation") have been made
> changes which can cause multiply overflow for 32-bit systems.
Awesome, thx for quickly narrowing it down. I tried the fix and it cures my issue.
It was caught on arc/hsdk board
> when "drto_ms" should be 671, but it was 70 and that caused a flow of stack-traces just copying
> file from mmc.
IMHO, the fragment above could be improved.
"The broken timeout calculations caused false interrupt latency warnings
and stacktrace splat (such as below) when accessing the SD Card."
| Running : 4M-check-reassembly-tcp-cmykw2-rotatew2.out -v0 -w1
| - Info: Finished target initialization.
| mmcblk0: error -110 transferring data, sector 320544, nr 2048, cmd response
| 0x900, card status 0x0
| mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 400000Hz, actual
| 396825HZ div = 63)
| mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 25000000Hz, actual
| 25000000HZ div = 1)
| ------------[ cut here ]------------
| softirq: huh, entered softirq 6 TASKLET 6f6a9412 with preempt_count 00000101,
| exited with 00000100?
| WARNING: CPU: 2 PID: 0 at ../lib/scatterlist.c:652 sg_miter_next+0x28/0x20c
| Modules linked in:
| CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.15.0 #57
|
| Stack Trace:
| arc_unwind_core.constprop.1+0xd0/0xf4
| dump_stack+0x68/0x80
| warn_slowpath_null+0x4e/0xec
| sg_miter_next+0x28/0x20c
| dw_mci_read_data_pio+0x44/0x190
| dw_mmc f000a000.mmc: Unexpected interrupt latency
| dw_mci_interrupt+0x3ee/0x530
| __handle_irq_event_percpu+0x56/0x150
| handle_irq_event+0x34/0x78
| handle_level_irq+0x8e/0x120
| generic_handle_irq+0x1c/0x2c
| idu_cascade_isr+0x30/0x6c
| __handle_domain_irq+0x72/0xc8
| ret_from_exception+0x0/0x8
|---[ end trace 2a58c9af6c25fe51 ]---
>
> Lets cast this multiply to long long int which prevents overflow.
>
> Signed-off-by: Evgeniy Didin <Evgeniy.Didin at synopsys.com>
> CC: Alexey Brodkin <abrodkin at synopsys.com>
> CC: Douglas Anderson <dianders at chromium.org>
> CC: Ulf Hansson <ulf.hansson at linaro.org>
> CC: linux-kernel at vger.kernel.org
> CC: linux-snps-arc at lists.infradead.org
Tested-by: Vineet Gupta <vgupta at synopsys.com>
Fixes: ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files
> ---
> drivers/mmc/host/dw_mmc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 0aa39975f33b..1a0b9751c67c 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1944,7 +1944,7 @@ static void dw_mci_set_drto(struct dw_mci *host)
> drto_div = (mci_readl(host, CLKDIV) & 0xff) * 2;
> if (drto_div == 0)
> drto_div = 1;
> - drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div,
> + drto_ms = DIV_ROUND_UP((uint64_t)MSEC_PER_SEC * drto_clks * drto_div,
> host->bus_hz);
>
> /* add a bit spare time */
>
