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Subjectthe magic in do_page_fault() ???
Hi LKML:

I am reading code of memory management. this process is so challengable.

I have one quetion too.

in do_page_fault() (kernel 2.6.11.11) include one piece of code as
follow:


if (!down_read_trylock(&mm->mmap_sem)) {
if ((error_code & 4) == 0 &&
!search_exception_tables(regs->eip))
goto bad_area_nosemaphore;
down_read(&mm->mmap_sem);
}


I think I can understand these operations on mm->mmap_sem and
"error_code&4".
but how "search_exception_tables(regs->eip)" work here?

In "Understanding Linux kernel 2ed" book, the author say , kernel
must difference two case:

1. kernel memory access problem.
2. Arguments of system call include address of memeory unit is
unmapped.

Well, That is OK. but I want to know what 's mechanism in it ?

3ks. (in Chinese , number 3 read as 'th' :)


liyu
Mon Jul
4 13:23:24 CST 2005






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