* printk issue - bug?
@ 2009-03-07 23:37 Adrian McMenamin
2009-03-07 23:52 ` Roland Dreier
0 siblings, 1 reply; 4+ messages in thread
From: Adrian McMenamin @ 2009-03-07 23:37 UTC (permalink / raw)
To: LKML
I wonder if anyone can reproduce this behaviour on other architectures
(this was SH4)?
code is:
printk("PAGE_SIZE is 0x%X\n", PAGE_SIZE);
printk("Offset is 0x%X, PAGE_SIZE is 0x%X, readlen is 0x%X\n", offset,
PAGE_SIZE, readlen)
Output is:
[ 162.603348] PAGE_SIZE is 0x1000
[ 162.607473] Offset is 0x0, PAGE_SIZE is 0x0, readlen is 0x1000
ie PAGE_SIZE is incorrectly reported in the second printk (these are
consecutive lines of code)
offset is loff_t and readlen is unsigned long.
Adrian
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: printk issue - bug?
2009-03-07 23:37 printk issue - bug? Adrian McMenamin
@ 2009-03-07 23:52 ` Roland Dreier
2009-03-08 1:04 ` Adrian McMenamin
0 siblings, 1 reply; 4+ messages in thread
From: Roland Dreier @ 2009-03-07 23:52 UTC (permalink / raw)
To: Adrian McMenamin; +Cc: LKML
> printk("PAGE_SIZE is 0x%X\n", PAGE_SIZE);
> printk("Offset is 0x%X, PAGE_SIZE is 0x%X, readlen is 0x%X\n", offset,
> PAGE_SIZE, readlen)
>
> Output is:
>
> [ 162.603348] PAGE_SIZE is 0x1000
> [ 162.607473] Offset is 0x0, PAGE_SIZE is 0x0, readlen is 0x1000
>
> ie PAGE_SIZE is incorrectly reported in the second printk (these are
> consecutive lines of code)
>
> offset is loff_t and readlen is unsigned long.
ie offset is a 64-bit type but the printk format for it is %x, which
presumably only consumes 32 bits on SH4? Seems like your code is buggy
and you ignored a compiler warning about printk format mismatch?
- R.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: printk issue - bug?
2009-03-07 23:52 ` Roland Dreier
@ 2009-03-08 1:04 ` Adrian McMenamin
2009-03-08 2:20 ` Robert Hancock
0 siblings, 1 reply; 4+ messages in thread
From: Adrian McMenamin @ 2009-03-08 1:04 UTC (permalink / raw)
To: Roland Dreier; +Cc: LKML
2009/3/7 Roland Dreier <rdreier@cisco.com>:
>
> ie offset is a 64-bit type but the printk format for it is %x, which
> presumably only consumes 32 bits on SH4? Seems like your code is buggy
> and you ignored a compiler warning about printk format mismatch?
>
> - R.
>
Yes, loff_t is a long long but why did it work in the first line and
not the second?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: printk issue - bug?
2009-03-08 1:04 ` Adrian McMenamin
@ 2009-03-08 2:20 ` Robert Hancock
0 siblings, 0 replies; 4+ messages in thread
From: Robert Hancock @ 2009-03-08 2:20 UTC (permalink / raw)
To: Adrian McMenamin; +Cc: Roland Dreier, LKML
Adrian McMenamin wrote:
> 2009/3/7 Roland Dreier <rdreier@cisco.com>:
>
>> ie offset is a 64-bit type but the printk format for it is %x, which
>> presumably only consumes 32 bits on SH4? Seems like your code is buggy
>> and you ignored a compiler warning about printk format mismatch?
>>
>> - R.
>>
>
> Yes, loff_t is a long long but why did it work in the first line and
> not the second?
It didn't. You didn't print loff_t in the first printk, and the variable
size mismatch corrupted the next value being printed in the second one.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-03-08 2:20 UTC | newest]
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2009-03-07 23:37 printk issue - bug? Adrian McMenamin
2009-03-07 23:52 ` Roland Dreier
2009-03-08 1:04 ` Adrian McMenamin
2009-03-08 2:20 ` Robert Hancock
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