ptrace patch in 2.4.0test8-pre4 breaks ups

From: Andi Kleen (ak@suse.de)
Date: Sun Sep 17 2000 - 12:44:35 EST


Hallo,

The following patch added in 2.4.0test8-pre4 breaks ups (an alternative
source level debugger that does not use gdb):

--- v2.4.0-test7/linux/arch/i386/kernel/ptrace.c Fri Jun 23 21:55:07 2000
+++ linux/arch/i386/kernel/ptrace.c Sat Sep 2 12:00:02 2000
@@ -99,6 +99,11 @@
                case EFL:
                        value &= FLAG_MASK;
                        value |= get_stack_long(child, EFL_OFFSET) & ~FLAG_MASK;
+ break;
+ case EIP:
+ /* Mark us as not being in a system call, so that no restart issues happen */
+ put_stack_long(child, 4*ORIG_EAX - sizeof(struct pt_regs), -1);
+ break;
        }
        if (regno > GS*4)
                regno -= 2*4;

When it tries to set EIP after the first break point the program crashes now:

[....]
ptrace(PTRACE_PEEKTEXT, 500, 0x4000ab10, [0x89e58955]) = 0
ptrace(PTRACE_POKETEXT, 500, 0x4000ab10, 0x89e589cc) = 0
ptrace(PTRACE_POKEUSER, 500, 4*EIP, 0x8048406) = 0
ptrace(PTRACE_SINGLESTEP, 500, 0x1, 0) = 0
--- SIGCHLD (Child exited) ---
rt_sigaction(SIGIO, {0x80c9f80, [PROF IO], 0}, {SIG_DFL}) = 0
fcntl(4, F_SETFL, O_RDONLY|O_ASYNC) = 0
wait4(-1, [WIFSIGNALED(s) && WTERMSIG(s) == SIGSEGV], WNOHANG, NULL) = 500

With the EIP patch reverted it works fine again. I propose to revert the patch.

-Andi

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sat Sep 23 2000 - 21:00:15 EST