On Sat, Feb 13, 2010 at 10:29:16PM +0100, Michael Stefaniuc wrote:Although Wine will map address 0x0 for DOS programs that isn't the reason for those tests. Wine has to support games that come with pointless copy protection schemes that employ that technique.Results 2.6.33-rcX:
-------------------
ptrace(PTRACE_ATTACH, 18036, 0, 0) = 0
ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg),
0x42424242) = 0
ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 4, 0) = 0
ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 8, 0) = 0
ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 12,
0) = 0
ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 24,
0) = 0
ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 28,
0x155) = -1 EINVAL (Invalid argument)
Results 2.6.32:
---------------
trace(PTRACE_ATTACH, 3077, 0, 0) = 0
ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg),
0x42424242) = 0
ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 4, 0) = 0
ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 8, 0) = 0
ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 12, 0) = 0
ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 24, 0) = 0
ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 28,
0x155) = 0
I see... So this is setting breakpoints on the address 0. The new code
rejects such breakpoints, but the previous one was accepting it.
The point of allowing breakpoints in NULL is discutable. It's not a bug,
neither is it a security hole I think (because if the ptrace breakpoint
triggers from the kernel, it's ignored), it's just pointless, unless
userland map things in 0.
But it's too late to debate this. If the previous code accepted it,Cool, thanks!
it's an ABI, and we have broken it.
I'm preparing a fix.
I cannot test that as the corresponding test is directly affected by this ABI change.So it looks like something in the setting of DR7 is broken or at leastOk.
changed behavior. The function in Wine that does those calls is
set_thread_context() from server/ptrace.c .
I'll try to see if I can reproduce the other regression; as it is hidden
at the moment by this regression.