mmc: dw_mmc: Fix the DTO timeout overflow calculation for 32-bit systems

Message ID 20180221175734.39114-1-Evgeniy.Didin@synopsys.com
State New
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Series
  • mmc: dw_mmc: Fix the DTO timeout overflow calculation for 32-bit systems
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Commit Message

Evgeniy Didin Feb. 21, 2018, 5:57 p.m.
In commit 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation") have been made
changes which can cause multiply overflow for 32-bit systems. 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.

Lets cast this multiply to long long int which prevents overflow.

Signed-off-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
CC: Alexey Brodkin <abrodkin@synopsys.com>
CC: Douglas Anderson <dianders@chromium.org>
CC: Ulf Hansson <ulf.hansson@linaro.org>
CC: linux-kernel@vger.kernel.org
CC: linux-snps-arc@lists.infradead.org
---
 drivers/mmc/host/dw_mmc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Andy Shevchenko Feb. 21, 2018, 7:16 p.m. | #1
On Wed, Feb 21, 2018 at 7:57 PM, Evgeniy Didin
<Evgeniy.Didin@synopsys.com> 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. 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.
>
> Lets cast this multiply to long long int which prevents overflow.
>
> Signed-off-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
> CC: Alexey Brodkin <abrodkin@synopsys.com>
> CC: Douglas Anderson <dianders@chromium.org>
> CC: Ulf Hansson <ulf.hansson@linaro.org>
> CC: linux-kernel@vger.kernel.org
> CC: linux-snps-arc@lists.infradead.org

> --- 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);

Does the driver use uint64_t elsewhere?
Or simple u64?
Vineet Gupta Feb. 21, 2018, 7:24 p.m. | #2
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@synopsys.com>
> CC: Alexey Brodkin <abrodkin@synopsys.com>
> CC: Douglas Anderson <dianders@chromium.org>
> CC: Ulf Hansson <ulf.hansson@linaro.org>
> CC: linux-kernel@vger.kernel.org
> CC: linux-snps-arc@lists.infradead.org

Tested-by: Vineet Gupta <vgupta@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 */
>
kbuild test robot Feb. 23, 2018, 1:14 a.m. | #3
Hi Evgeniy,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.16-rc2 next-20180222]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Evgeniy-Didin/mmc-dw_mmc-Fix-the-DTO-timeout-overflow-calculation-for-32-bit-systems/20180223-054846
config: arm-exynos_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

All errors (new ones prefixed by >>):

   drivers/mmc/host/dw_mmc.o: In function `dw_mci_set_drto':
>> dw_mmc.c:(.text+0x1644): undefined reference to `__aeabi_uldivmod'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kbuild test robot Feb. 23, 2018, 8:34 a.m. | #4
Hi Evgeniy,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.16-rc2 next-20180223]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Evgeniy-Didin/mmc-dw_mmc-Fix-the-DTO-timeout-overflow-calculation-for-32-bit-systems/20180223-054846
config: mips-pistachio_defconfig (attached as .config)
compiler: mipsel-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=mips 

All errors (new ones prefixed by >>):

   drivers/mmc/host/dw_mmc.o: In function `dw_mci_set_drto':
>> dw_mmc.c:(.text+0x176c): undefined reference to `__udivdi3'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Patch

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 */