diff mbox series

SPI regression seen on ARM am335x in kernel 6.12.8 and 6.6.71

Message ID CAKd8=GsoKj5eG6VAMkrxMbzNyoBX=JiwafrfXman8xMNK+XU_w@mail.gmail.com (mailing list archive)
State New
Headers show
Series SPI regression seen on ARM am335x in kernel 6.12.8 and 6.6.71 | expand

Commit Message

Lars Pedersen Jan. 16, 2025, 2:21 p.m. UTC 
Hi. We have discovered an SPI regression when upgrading from 6.1.99 to
a newer LTS version. Same error on kernel 6.6.71 and 6.12.8.

I think we have identified the problem down to the reference clock
calculation that seems to end up to zero in the spi-omap2-mcspi
driver.

Also we think it relates to commit
4c6ac5446d060f0bf435ccc8bc3aa7b7b5f718ad, where OMAP2_MCSPI_MAX_FREQ
is used as fallback on error. In our case it seems to hit the else
case.

Snippets for device tree, spi-omap2-mcspi driver and kernel divide by
zero error log with dynamic debug enabled.

/Lars Pedersen


---8<---
/dts-v1/;

#include "am33xx.dtsi"
#include <dt-bindings/interrupt-controller/irq.h>
...

&spi0 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&spi0_pins_default>;
ti,spi-num-cs = <1>;

flash@0 {
compatible = "jedec,spi-nor";
reg = <0>;
spi-tx-bus-width = <1>;
spi-rx-bus-width = <1>;
spi-max-frequency = <10000000>;

partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
reg = <0x0 0x1f00000>;
label = "radio-program";
};
partition@1f00000 {
reg = <0x1f00000 0xe0000>;
label = "linux-data";
read-only;
};
partition@1fe0000 {
reg = <0x1fe0000 0x10000>;
label = "radio-config";
read-only;
};
partition@1ff0000 {
reg = <0x1ff0000 0x10000>;
label = "baseband-config";
read-only;
};
};
};
};

---8<---
Jan 16 11:30:53 ptxdist kernel: omap2_mcspi 48030000.spi: DEBUG_EXTRA pre calc
Jan 16 11:30:54 ptxdist kernel: omap2_mcspi 48030000.spi: DEBUG_EXTRA:
ref_clk_hz 0
Jan 16 11:30:54 ptxdist kernel: omap2_mcspi 48030000.spi: registered host spi0
Jan 16 11:30:54 ptxdist kernel: Division by zero in kernel.
Jan 16 11:30:54 ptxdist kernel: CPU: 0 UID: 0 PID: 161 Comm:
(udev-worker) Not tainted 6.12.8 #1
Jan 16 11:30:54 ptxdist kernel: Hardware name: Generic AM33XX
(Flattened Device Tree)
Jan 16 11:30:54 ptxdist kernel: Call trace:
Jan 16 11:30:54 ptxdist kernel:  dump_backtrace from show_stack+0x20/0x38
Jan 16 11:30:54 ptxdist kernel:  r7:c4a7ff00 r6:c0cef6bc r5:00000000 r4:600f0113
Jan 16 11:30:54 ptxdist kernel:  show_stack from dump_stack_lvl+0x40/0x78
Jan 16 11:30:54 ptxdist kernel:  dump_stack_lvl from dump_stack+0x18/0x28
Jan 16 11:30:54 ptxdist kernel:  r7:c4a7ff00 r6:00000008 r5:c477dbc0 r4:c4a7ec00
Jan 16 11:30:54 ptxdist kernel:  dump_stack from __div0+0x24/0x34
Jan 16 11:30:54 ptxdist kernel:  __div0 from Ldiv0+0x8/0x10
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_setup_transfer
[spi_omap2_mcspi] from omap2_mcspi_setup+0x134/0x20c [spi_omap2_mcspi]
Jan 16 11:30:54 ptxdist kernel:  r9:c4a7ff28 r8:c477dbd0 r7:c4a7ff00
r6:c4a7ec00 r5:c2572c10 r4:00000001
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_setup [spi_omap2_mcspi]
from spi_setup+0x124/0x4f8
Jan 16 11:30:54 ptxdist kernel:  r9:c4a7edaf r8:00000000 r7:c2572c10
r6:c4a7fc00 r5:00000000 r4:c4a7ec00
Jan 16 11:30:54 ptxdist kernel:  spi_setup from __spi_add_device+0x15c/0x300
Jan 16 11:30:54 ptxdist kernel:  r6:c4a7fc00 r5:c4a7ec00 r4:c4a7ed9f
Jan 16 11:30:54 ptxdist kernel:  __spi_add_device from
of_register_spi_devices+0x74/0x1a8
Jan 16 11:30:54 ptxdist kernel:  r10:c0fe67cc r9:c4a7fd98 r8:c4a7fdd4
r7:c4a7ec00 r6:c4a7fc00 r5:00000000
Jan 16 11:30:54 ptxdist kernel:  r4:cfce0df4
Jan 16 11:30:54 ptxdist kernel:  of_register_spi_devices from
spi_register_controller+0x3d0/0x4d0
Jan 16 11:30:54 ptxdist kernel:  r9:c4a7fd98 r8:c0fe67d4 r7:c4a7fda0
r6:00000000 r5:c0fe67d4 r4:c4a7fc00
Jan 16 11:30:54 ptxdist kernel:  spi_register_controller from
devm_spi_register_controller+0x54/0xbc
Jan 16 11:30:54 ptxdist kernel:  r10:bf006108 r9:c2572c10 r8:c4a7fc00
r7:c2572c10 r6:c4a7fc00 r5:c4a7ff00
Jan 16 11:30:54 ptxdist kernel:  r4:c46cd2c0
Jan 16 11:30:54 ptxdist kernel:  devm_spi_register_controller from
omap2_mcspi_probe+0x51c/0x5cc [spi_omap2_mcspi]
Jan 16 11:30:54 ptxdist kernel:  r7:c4a7fc00 r6:c2572c10 r5:c4a7ff00 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_probe [spi_omap2_mcspi]
from platform_probe+0x6c/0xd0
Jan 16 11:30:54 ptxdist kernel:  r10:d0481ed0 r9:00000001 r8:00000000
r7:c1028ef8 r6:bf004014 r5:c2572c10
Jan 16 11:30:54 ptxdist kernel:  r4:00000000
Jan 16 11:30:54 ptxdist kernel:  platform_probe from really_probe+0xf0/0x3ec
Jan 16 11:30:54 ptxdist kernel:  r7:c1028ef8 r6:bf004014 r5:00000000 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  really_probe from
__driver_probe_device+0xac/0x13c
Jan 16 11:30:54 ptxdist kernel:  r8:c27a50b4 r7:0000007d r6:c2572c10
r5:bf004014 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  __driver_probe_device from
driver_probe_device+0x40/0xe4
Jan 16 11:30:54 ptxdist kernel:  r5:bf004014 r4:c1071d9c
Jan 16 11:30:54 ptxdist kernel:  driver_probe_device from
__driver_attach+0x154/0x204
Jan 16 11:30:54 ptxdist kernel:  r7:00000000 r6:c2572c54 r5:bf004014 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  __driver_attach from bus_for_each_dev+0x8c/0xf0
Jan 16 11:30:54 ptxdist kernel:  r7:00000000 r6:c20e96c0 r5:c06404ec r4:bf004014
Jan 16 11:30:54 ptxdist kernel:  bus_for_each_dev from driver_attach+0x2c/0x44
Jan 16 11:30:54 ptxdist kernel:  r7:c20e96c0 r6:00000000 r5:c27a5080 r4:bf004014
Jan 16 11:30:54 ptxdist kernel:  driver_attach from bus_add_driver+0x104/0x244
Jan 16 11:30:54 ptxdist kernel:  bus_add_driver from driver_register+0x8c/0x164
Jan 16 11:30:54 ptxdist kernel:  r8:00000000 r7:bf004100 r6:c101f840
r5:a7ac7714 r4:bf004014
Jan 16 11:30:54 ptxdist kernel:  driver_register from
__platform_driver_register+0x2c/0x40
Jan 16 11:30:54 ptxdist kernel:  r5:a7ac7714 r4:c0fac2fc
Jan 16 11:30:54 ptxdist kernel:  __platform_driver_register from
omap2_mcspi_driver_init+0x38/0x1000 [spi_omap2_mcspi]
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_driver_init
[spi_omap2_mcspi] from do_one_initcall+0x68/0x2b8
Jan 16 11:30:54 ptxdist kernel:  r5:c2a95800 r4:bf008000
Jan 16 11:30:54 ptxdist kernel:  do_one_initcall from do_init_module+0x64/0x218
Jan 16 11:30:54 ptxdist kernel:  r8:bf004100 r7:bf004100 r6:c477d240
r5:00000000 r4:bf004100
Jan 16 11:30:54 ptxdist kernel:  do_init_module from load_module+0x7e4/0xa18
Jan 16 11:30:54 ptxdist kernel:  r6:00000000 r5:00000000 r4:00000000
Jan 16 11:30:54 ptxdist kernel:  load_module from
init_module_from_file+0xa4/0xec
Jan 16 11:30:54 ptxdist kernel:  r10:c477c080 r9:c1054a48 r8:c477c080
r7:c1054a38 r6:b5b1d7f0 r5:c477c080
Jan 16 11:30:54 ptxdist kernel:  r4:00000000
Jan 16 11:30:54 ptxdist kernel:  init_module_from_file from
sys_finit_module+0x244/0x39c
Jan 16 11:30:54 ptxdist kernel:  r6:00000001 r5:000000f4 r4:c2a95800
Jan 16 11:30:54 ptxdist kernel:  sys_finit_module from
__sys_trace_return+0x0/0x10
Jan 16 11:30:54 ptxdist kernel: Exception stack(0xd0481fa8 to 0xd0481ff0)
Jan 16 11:30:54 ptxdist kernel: 1fa0:                   14cb6a00
00000000 0000001a b5b1d7f0 00000000 00000000
Jan 16 11:30:54 ptxdist kernel: 1fc0: 14cb6a00 00000000 00826358
0000017b 008456d0 b6f75934 b5b1739d 00000000
Jan 16 11:30:54 ptxdist kernel: 1fe0: bee9d538 bee9d528 b5b16643 b6c5d262
Jan 16 11:30:54 ptxdist kernel:  r10:0000017b r9:c2a95800 r8:c01002c4
r7:0000017b r6:00826358 r5:00000000
Jan 16 11:30:54 ptxdist kernel:  r4:14cb6a00
Jan 16 11:30:54 ptxdist kernel: Division by zero in kernel.
Jan 16 11:30:54 ptxdist kernel: CPU: 0 UID: 0 PID: 161 Comm:
(udev-worker) Not tainted 6.12.8 #1
Jan 16 11:30:54 ptxdist kernel: Hardware name: Generic AM33XX
(Flattened Device Tree)
Jan 16 11:30:54 ptxdist kernel: Call trace:
Jan 16 11:30:54 ptxdist kernel:  dump_backtrace from show_stack+0x20/0x38
Jan 16 11:30:54 ptxdist kernel:  r7:c4a7ff00 r6:c0cef6bc r5:00000000 r4:600f0113
Jan 16 11:30:54 ptxdist kernel:  show_stack from dump_stack_lvl+0x40/0x78
Jan 16 11:30:54 ptxdist kernel:  dump_stack_lvl from dump_stack+0x18/0x28
Jan 16 11:30:54 ptxdist kernel:  r7:c4a7ff00 r6:00000008 r5:c477dbc0 r4:c4a7ec00
Jan 16 11:30:54 ptxdist kernel:  dump_stack from __div0+0x24/0x34
Jan 16 11:30:54 ptxdist kernel:  __div0 from Ldiv0+0x8/0x10
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_setup_transfer
[spi_omap2_mcspi] from omap2_mcspi_setup+0x134/0x20c [spi_omap2_mcspi]
Jan 16 11:30:54 ptxdist kernel:  r9:c4a7ff28 r8:c477dbd0 r7:c4a7ff00
r6:c4a7ec00 r5:c2572c10 r4:00000001
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_setup [spi_omap2_mcspi]
from spi_setup+0x124/0x4f8
Jan 16 11:30:54 ptxdist kernel:  r9:c4a7edaf r8:00000000 r7:c2572c10
r6:c4a7fc00 r5:00000000 r4:c4a7ec00
Jan 16 11:30:54 ptxdist kernel:  spi_setup from __spi_add_device+0x15c/0x300
Jan 16 11:30:54 ptxdist kernel:  r6:c4a7fc00 r5:c4a7ec00 r4:c4a7ed9f
Jan 16 11:30:54 ptxdist kernel:  __spi_add_device from
of_register_spi_devices+0x74/0x1a8
Jan 16 11:30:54 ptxdist kernel:  r10:c0fe67cc r9:c4a7fd98 r8:c4a7fdd4
r7:c4a7ec00 r6:c4a7fc00 r5:00000000
Jan 16 11:30:54 ptxdist kernel:  r4:cfce0df4
Jan 16 11:30:54 ptxdist kernel:  of_register_spi_devices from
spi_register_controller+0x3d0/0x4d0
Jan 16 11:30:54 ptxdist kernel:  r9:c4a7fd98 r8:c0fe67d4 r7:c4a7fda0
r6:00000000 r5:c0fe67d4 r4:c4a7fc00
Jan 16 11:30:54 ptxdist kernel:  spi_register_controller from
devm_spi_register_controller+0x54/0xbc
Jan 16 11:30:54 ptxdist kernel:  r10:bf006108 r9:c2572c10 r8:c4a7fc00
r7:c2572c10 r6:c4a7fc00 r5:c4a7ff00
Jan 16 11:30:54 ptxdist kernel:  r4:c46cd2c0
Jan 16 11:30:54 ptxdist kernel:  devm_spi_register_controller from
omap2_mcspi_probe+0x51c/0x5cc [spi_omap2_mcspi]
Jan 16 11:30:54 ptxdist kernel:  r7:c4a7fc00 r6:c2572c10 r5:c4a7ff00 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_probe [spi_omap2_mcspi]
from platform_probe+0x6c/0xd0
Jan 16 11:30:54 ptxdist kernel:  r10:d0481ed0 r9:00000001 r8:00000000
r7:c1028ef8 r6:bf004014 r5:c2572c10
Jan 16 11:30:54 ptxdist kernel:  r4:00000000
Jan 16 11:30:54 ptxdist kernel:  platform_probe from really_probe+0xf0/0x3ec
Jan 16 11:30:54 ptxdist kernel:  r7:c1028ef8 r6:bf004014 r5:00000000 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  really_probe from
__driver_probe_device+0xac/0x13c
Jan 16 11:30:54 ptxdist kernel:  r8:c27a50b4 r7:0000007d r6:c2572c10
r5:bf004014 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  __driver_probe_device from
driver_probe_device+0x40/0xe4
Jan 16 11:30:54 ptxdist kernel:  r5:bf004014 r4:c1071d9c
Jan 16 11:30:54 ptxdist kernel:  driver_probe_device from
__driver_attach+0x154/0x204
Jan 16 11:30:54 ptxdist kernel:  r7:00000000 r6:c2572c54 r5:bf004014 r4:c2572c10
Jan 16 11:30:54 ptxdist kernel:  __driver_attach from bus_for_each_dev+0x8c/0xf0
Jan 16 11:30:54 ptxdist kernel:  r7:00000000 r6:c20e96c0 r5:c06404ec r4:bf004014
Jan 16 11:30:54 ptxdist kernel:  bus_for_each_dev from driver_attach+0x2c/0x44
Jan 16 11:30:54 ptxdist kernel:  r7:c20e96c0 r6:00000000 r5:c27a5080 r4:bf004014
Jan 16 11:30:54 ptxdist kernel:  driver_attach from bus_add_driver+0x104/0x244
Jan 16 11:30:54 ptxdist kernel:  bus_add_driver from driver_register+0x8c/0x164
Jan 16 11:30:54 ptxdist kernel:  r8:00000000 r7:bf004100 r6:c101f840
r5:a7ac7714 r4:bf004014
Jan 16 11:30:54 ptxdist kernel:  driver_register from
__platform_driver_register+0x2c/0x40
Jan 16 11:30:54 ptxdist kernel:  r5:a7ac7714 r4:c0fac2fc
Jan 16 11:30:54 ptxdist kernel:  __platform_driver_register from
omap2_mcspi_driver_init+0x38/0x1000 [spi_omap2_mcspi]
Jan 16 11:30:54 ptxdist kernel:  omap2_mcspi_driver_init
[spi_omap2_mcspi] from do_one_initcall+0x68/0x2b8
Jan 16 11:30:54 ptxdist kernel:  r5:c2a95800 r4:bf008000
Jan 16 11:30:54 ptxdist kernel:  do_one_initcall from do_init_module+0x64/0x218
Jan 16 11:30:54 ptxdist kernel:  r8:bf004100 r7:bf004100 r6:c477d240
r5:00000000 r4:bf004100
Jan 16 11:30:54 ptxdist kernel:  do_init_module from load_module+0x7e4/0xa18
Jan 16 11:30:54 ptxdist kernel:  r6:00000000 r5:00000000 r4:00000000
Jan 16 11:30:54 ptxdist kernel:  load_module from
init_module_from_file+0xa4/0xec
Jan 16 11:30:54 ptxdist kernel:  r10:c477c080 r9:c1054a48 r8:c477c080
r7:c1054a38 r6:b5b1d7f0 r5:c477c080
Jan 16 11:30:54 ptxdist kernel:  r4:00000000
Jan 16 11:30:54 ptxdist kernel:  init_module_from_file from
sys_finit_module+0x244/0x39c
Jan 16 11:30:54 ptxdist kernel:  r6:00000001 r5:000000f4 r4:c2a95800
Jan 16 11:30:54 ptxdist kernel:  sys_finit_module from
__sys_trace_return+0x0/0x10
Jan 16 11:30:54 ptxdist kernel: Exception stack(0xd0481fa8 to 0xd0481ff0)
Jan 16 11:30:54 ptxdist kernel: 1fa0:                   14cb6a00
00000000 0000001a b5b1d7f0 00000000 00000000
Jan 16 11:30:54 ptxdist kernel: 1fc0: 14cb6a00 00000000 00826358
0000017b 008456d0 b6f75934 b5b1739d 00000000
Jan 16 11:30:55 ptxdist kernel: 1fe0: bee9d538 bee9d528 b5b16643 b6c5d262
Jan 16 11:30:55 ptxdist kernel:  r10:0000017b r9:c2a95800 r8:c01002c4
r7:0000017b r6:00826358 r5:00000000
Jan 16 11:30:55 ptxdist kernel:  r4:14cb6a00
Jan 16 11:30:55 ptxdist kernel: spi spi0.0: setup: speed 0, sample
leading edge, clk normal
Jan 16 11:30:55 ptxdist kernel: spi spi0.0: setup mode 0, 8 bits/w,
10000000 Hz max --> 0

Comments

Greg KH Jan. 17, 2025, 12:32 p.m. UTC | #1 
On Thu, Jan 16, 2025 at 03:21:13PM +0100, Lars Pedersen wrote:
> Hi. We have discovered an SPI regression when upgrading from 6.1.99 to
> a newer LTS version. Same error on kernel 6.6.71 and 6.12.8.
> 
> I think we have identified the problem down to the reference clock
> calculation that seems to end up to zero in the spi-omap2-mcspi
> driver.
> 
> Also we think it relates to commit
> 4c6ac5446d060f0bf435ccc8bc3aa7b7b5f718ad, where OMAP2_MCSPI_MAX_FREQ
> is used as fallback on error. In our case it seems to hit the else
> case.
> 
> Snippets for device tree, spi-omap2-mcspi driver and kernel divide by
> zero error log with dynamic debug enabled.

If you revert the offending commit, does that solve the issue?

thanks,

greg k-h
Lars Pedersen Jan. 17, 2025, 2:49 p.m. UTC | #2 
On Fri, 17 Jan 2025 at 13:32, Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Thu, Jan 16, 2025 at 03:21:13PM +0100, Lars Pedersen wrote:
> > Hi. We have discovered an SPI regression when upgrading from 6.1.99 to
> > a newer LTS version. Same error on kernel 6.6.71 and 6.12.8.
> >
> > I think we have identified the problem down to the reference clock
> > calculation that seems to end up to zero in the spi-omap2-mcspi
> > driver.
> >
> > Also we think it relates to commit
> > 4c6ac5446d060f0bf435ccc8bc3aa7b7b5f718ad, where OMAP2_MCSPI_MAX_FREQ
> > is used as fallback on error. In our case it seems to hit the else
> > case.
> >
> > Snippets for device tree, spi-omap2-mcspi driver and kernel divide by
> > zero error log with dynamic debug enabled.
>
> If you revert the offending commit, does that solve the issue?
>
> thanks,
>
> greg k-h

Hi Greg.

No it doesn't solve the issue by reverting the commit. The commit
isn't the regression, but it attempts to handle it in the if/else
statement. Everything starts to work again if we hard code it to
"mcspi->ref_clk_hz = OMAP2_MCSPI_MAX_FREQ;", so it seems like the if
else statement isn't 100% foolproof (or we have missed a setting in
the device tree).

Thanks

/Lars Pedersen
diff mbox series

Patch

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 67441b2cd603..8fedfc7db1fa 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -1559,12 +1559,13 @@  static int omap2_mcspi_probe(struct
platform_device *pdev)
                dev_err(&pdev->dev, "Cannot request IRQ");
                goto free_ctlr;
        }
-
+       dev_dbg(&pdev->dev, "DEBUG_EXTRA pre calc\n");
        mcspi->ref_clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
        if (IS_ERR(mcspi->ref_clk))
                mcspi->ref_clk_hz = OMAP2_MCSPI_MAX_FREQ;
        else
                mcspi->ref_clk_hz = clk_get_rate(mcspi->ref_clk);
+       dev_dbg(&pdev->dev, "DEBUG_EXTRA: ref_clk_hz %d\n", mcspi->ref_clk_hz);
        ctlr->max_speed_hz = mcspi->ref_clk_hz;
        ctlr->min_speed_hz = mcspi->ref_clk_hz >> 15;