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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2006-04-20 06:41:39 +0900
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-19 16:27:18 -0700
commit5a7b46b369419493bab4de67b1526e9f76b22a7f (patch)
treec6c25e52dfd063db53db93d756da77ab67550ec6 /kernel/kprobes.c
parent52824b6b5fa0533e2b2adc9df396d0e9ff6fb02a (diff)
downloadlinux-5a7b46b369419493bab4de67b1526e9f76b22a7f.tar.gz
[PATCH] Add more prevent_tail_call()
Those also break userland regs like following.

   00000000 <sys_chown16>:
      0:	0f b7 44 24 0c       	movzwl 0xc(%esp),%eax
      5:	83 ca ff             	or     $0xffffffff,%edx
      8:	0f b7 4c 24 08       	movzwl 0x8(%esp),%ecx
      d:	66 83 f8 ff          	cmp    $0xffffffff,%ax
     11:	0f 44 c2             	cmove  %edx,%eax
     14:	66 83 f9 ff          	cmp    $0xffffffff,%cx
     18:	0f 45 d1             	cmovne %ecx,%edx
     1b:	89 44 24 0c          	mov    %eax,0xc(%esp)
     1f:	89 54 24 08          	mov    %edx,0x8(%esp)
     23:	e9 fc ff ff ff       	jmp    24 <sys_chown16+0x24>

where the tailcall at the end overwrites the incoming stack-frame.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
[ I would _really_ like to have a way to tell gcc about calling
  conventions. The "prevent_tail_call()" macro is pretty ugly ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/kprobes.c')
0 files changed, 0 insertions, 0 deletions