The code attached below segfaults on the enter instruction. It works
when a stack frame is created by the three commented out
instructions and also when the first operand of the enter instruction
is small (less than about 6500 on my system).
AFAIK, the only difference between creating a stack frame with the
enter instruction or push/mov/sub is that enter checks if the new
value of esp is inside the stack segment limit.
I tested it on a vanilla kernel 2.4.26 on Intel Celeron and also on
probably non-vanilla 2.6.16.13 running on 3 dual core AMD Opteron,
quite busy, server. It is working in 32-bit mode. Interestingly, on
the second machine sometimes the program worked correctly.
I am not subscribed to the list. Please cc replies to me.
.file "a.c"
.version "01.01"
gcc2_compiled.:
.section .rodata
.LC0:
.string "asdf\n"
.text
.align 4
.globl main
.type main,@function
main:
enter $10008, $0
# pushl %ebp
# movl %esp,%ebp
# subl $10008,%esp
addl $-12,%esp
pushl $.LC0
call printf
addl $16,%esp
.L2:
leave
ret
.Lfe1:
.size main,.Lfe1-main
.ident "GCC: (GNU) 2.95.4 20011002 (Debian prerelease)"
--
Tomek Malesinski
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