There is one return path in the __copy_user that do not restore the ar.lc register. This is causing applications that uses ar.lc to fail. Attached is a patch to fix it (file is also attached). Thanks, Asit --- linux-2.4.0/arch/ia64/lib/copy_user.S Thu Jan 4 12:50:17 2001 +++ linux/arch/ia64/lib/copy_user.S Tue Jan 9 05:35:36 2001 @@ -319,6 +319,7 @@ EX(failure_out,(EPI) st1 [dst1]=val1[PIPE_DEPTH-1],1) br.ctop.dptk.few 5b ;; + mov ar.lc=saved_lc mov pr=saved_pr,0xffffffffffff0000 mov ar.pfs=saved_pfs br.ret.dptk.few rp