[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>
1 file changed