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由 Chuck Ebbert 提交于
The i386 page fault handler does not allow enough slack when checking for userspace access below the current stack pointer. This prevents use of the enter instruction by user code. Fix this by allowing enough slack for "enter $65535,$31" to execute. Problem reported by Tomasz Malesinski <tmal@mimuw.edu.pl> Tested using this program, based on the original from Tomasz: .file "ovflow.S" .version "01.01" gcc2_compiled.: .section .rodata .LC0: .string "asdf\n" .text .align 4 .globl main .type main,@function main: nest_level=0 .rept 30 enter $0,$nest_level nest_level=nest_level+1 .endr enter $65535,$30 enter $65535,$31 addl $-12,%esp pushl $.LC0 call printf addl $16,%esp .L2: .rept 32 leave .endr ret .Lfe1: .size main,.Lfe1-main .ident "GCC: (GNU) 2.95.4 20011002 (Debian prerelease)" Signed-off-by: NChuck Ebbert <76306.1226@compuserve.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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