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@xxxxxxxxxxxx>
CC: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
CC: Douglas Anderson <dianders@xxxxxxxxxxxx>
CC: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
CC: linux-kernel@xxxxxxxxxxxxxxx
CC: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
Tested-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
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 */
--
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