On Wed, Aug 06, 2003 at 07:00:07PM +0800, Fuxin Zhang wrote:
> And here I have a question for Mr. Adam: original linux code use
> and "Hit_Invalidate_I",not "Writeback_D" and "Hit_Invalidate_I",could it
> lead to the
No. To synchronize the D-cache and I-cache it's irrelevant if you
invalidate the D-cache or not.
> a silly question: how can i make my email show up pretier? I find
> that the mailing list
> often break my lines very badly. I feel guilty for that:) I am using
> mozilla composer,the
> original linebreaks are manually inserted(hit enter when i feel it is
> long enough).
Format your email with hard breaks to about 75 columns. 75 columns
because god made vt100 with 80 columns so that leaves a bit of space for
quoting your mail nicely.
Now for your register dumps and information:
> (gdb) info reg
> t8 t9 k0 k1 gp sp s8 ra
> R24 00000000 00000000 00000000 00000000 1000d880 7fff7590 00000003 7fff75a0
> sr lo hi bad cause pc
> a004f413 000001b0 00000000 8009c6a0 80000028 7fff75b8
> 0x7fff75a0: li v0,4119
> 0x7fff75a4: syscall
So the pc is pointing just after the trampoline which suspiciously looks
like the return of an old bug. Could your application be doing something
unusual such as forking from a signal handler or similar? The scenario
- kernel installs signal trampoline on stack
- kernel forks. Now the signal trampoline installed in the first step
resides on a copy-on-write page.
- newly created process touches the cow page, thereby resulting in
breaking of the cow page. Now parent and child have their own copy
of the page. BUT: flush_cache_page() doesn't properly flush this page.
- Parent executes again on the copy of the page for which caches have
not been flushed proplerly in the previous step, thereby failing to
execute the trampoline - crash.