On Mon, 2018-07-09 at 12:49 +0200, Pavel Machek wrote:

Hi!

quoted

quoted

quoted

grep in /sys produces a nasty oops:

I guess next step is trying to find out which file that is..

Let me see...

openat(6, "suspend",
O_RDONLY|O_NOCTTY|O_NONBLOCK|O_LARGEFILE|O_NOFOLLOW) = 4
fstat64(4, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
read(4, 0x4d2000, 32768)                = -1 EINVAL (Invalid
argument)
write(2, "grep: ", 6grep: )                   = 6
write(2, "/sys/kernel/debug/pm_debug/cefus"...,
47/sys/kernel/debug/pm_debug/cefuse_pwrdm/suspend) = 47
write(2, ": Invalid argument", 18: Invalid argument)      = 18
write(2, "\n", 1
)                       = 1
close(4)                                = 0
close(6)                                = 0
openat(5, "time",
O_RDONLY|O_NOCTTY|O_NONBLOCK|O_LARGEFILE|O_NOFOLLOW)
= 4
fstat64(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
read(4, "cefuse_pwrdm (OFF),OFF:641441757"..., 32768) = 849
read(4, "", 28672)                      = 0
close(4)                                = 0
openat(5, "count",
O_RDONLY|O_NOCTTY|O_NONBLOCK|O_LARGEFILE|O_NOFOLLOW) = 4
Connection to usb closed by remote host.
Connection to usb closed.
pavel at half:~$

Ok, so it seems to be:

user at devuan:~$ cat /sys/kernel/debug/pm_debug/count
(oops).

The file seems to be world-readable.

user at devuan:~$ ls -al /sys/kernel/debug/pm_debug/count
-r--r--r-- 1 root root 0 Jan  1  1970
/sys/kernel/debug/pm_debug/count

But on PC, that file does not exist.

Ok, it is easier to reproduce like this:

sudo mount /dev/zero -t debugfs /sys/kernel/debug/
sudo cat /sys/kernel/debug/pm_debug/count

I tried adding debugging like this:

Confused.

quoted

 	seq_printf(s, "%s->%s (%d)\n", clkdm->name, clkdm-

quoted

pwrdm.ptr->name,

 		   clkdm->usecount);

I replaced seq_prinf with printk, and it still crashes, after
producing reasonable output.

You need to add printk to the show function as well. It might be last
item in the list which is problematic (or one after cefuse CLK domain.

[   74.852508] cmp...
[   74.855773] printf...
[   74.859313] l4_cfg_clkdm->core_pwrdm (0)
[   74.864532] done...
[   74.867889] cmp...
[   74.871154] printf...
[   74.874694] l4_cefuse_clkdm->cefuse_pwrdm (0)
[   74.880340] done...
[   74.883728] ------------[ cut here ]------------
[   74.889709] WARNING: CPU: 0 PID: 2127 at
drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x23c/0x380
[   74.900695] 44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4PER2
(Read): Data Access in User mode during Functional access
[   74.915222] Modules linked in:
[   74.919982] CPU: 0 PID: 2127 Comm: cat Not tainted
4.18.0-rc4-88970-gf075a2c-dirty #763
[   74.929870] Hardware name: Generic OMAP4 (Flattened Device Tree)
[   74.937805] [<c010f6cc>] (unwind_backtrace) from [<c010ba50>]
(show_stack+0x10/0x14)

									
Pavel

-- 
Andy Shevchenko [off-list ref]
Intel Finland Oy