> Since installing OSF/1 V3.2 less than a week ago, I have been plagued
> by a series of OS panics. The panics all seem to be related: Run a
> program that uses a large chunk of shared memory and make the system
> page a lot. I've run this program under dbx and often when dbx exits,
> the system panics with either:
>
> panic: pmap_release: page not found
> or
> panic: delete_pv_entry: mapping not in pv_list
The panics are caused by the debugger modifying pages in the program
beging debugged. For some reason, which Digital understands, but I don't,
when the debugger inserts a breakpoint, it modifies the virtual memory
of the process in a way which confuses the memory manager. When the
process is terminated, the virtual memory manager faults.
Two fixes were provided by the folks at Digital. One is to modify
/etc/sysconfigtab and set "vm-segmentation = 0". The other was in
the form of a patch to vm_umap.o. I did not get a chance to try
the sysconfigtab change, but with the patched vm_umap.o, I have
not experienced any further panics.
Thanks to all who responded, and especially Tim O'Neal from Digital
for researching and providing a patch.
John J. Lucak -----------------
Picker International, NMR Division -----------------
jjl_at_mr.picker.com -----------------
(216) 473-5452 -----------------
Received on Wed Mar 22 1995 - 17:35:29 NZST