On Friday 27 October 2006 08:57, Bart Smaalders wrote: > Eric Enright wrote: > > On 10/26/06, Robert Lunnon <[EMAIL PROTECTED]> wrote: > >> Can anyone give me an explanation of what exactly would cause a signal > >> for > >> Segmentation Violation - Page - Fault to be returned. The Memory region > >> accessed was previously accessed successfully then suddenly causes a > >> page fault. Is there a way to look at the page attributes of a memory > >> region in > >> mdb or gdb ? > > > > If it was accessed successfully and then not, there was probably a > > free(3C) somewhere in between.. pmap(1) will print attributes for you. > > > > [EMAIL PROTECTED]:~ (1)> pmap $$ > > 6298: /usr/bin/tcsh > > 08038000 64K rw--- [ stack ] > > 08050000 288K r-x-- /usr/bin/tcsh > > 080A7000 28K rwx-- /usr/bin/tcsh > > 080AE000 476K rwx-- [ heap ] > > D0D70000 20K r-x-- > > /usr/lib/locale/en_CA.ISO8859-1/en_CA.ISO8859-1.so.3 > > [...] > > > > (can also operate on a core) > > Note that a free using the normal libc malloc will not > cause the page to be unmapped, which is required to get > a segv. > > If you mmap a file MAP_SHARED and someone ftruncates the > file, this can happen. It can also happen if your process > simply unmaps the space itself. > > Pmap should indeed show the missing mapping. > > - Bart
mdb ::mappings dcmd shows the mapping exists OK, but I get a page fault accessiing it. Also both gdb and mdb misbehave with this app. mdb segfaults when printing regs from a signal handler and gdb faults with an unrelated segv in the application. Since the problem is a wine application the memory is played with from a protection point of view. Its almost like the pagetable is bad. Bob _______________________________________________ opensolaris-discuss mailing list [email protected]
