PATCH: 2.4.28: 32 bit ltrace oops when tracing 64 bit executable[X86_64]

From: Mark Bellon
Date: Wed Jan 05 2005 - 16:47:04 EST


Didn't see a fix for this so here it is. Tried using "ltrace -i" on a 64 bit executable when ltrace was a 32 bit executable. The kernel threw an oops.

The find_target routine (arch/x86/ia32/ptrace32.c) doesn't deal with a NULL return from find_task_by_pid properly - if NULL is returned put_task_struct() is still called.

mark



Index: arch/x86_64/ia32/ptrace32.c
===================================================================
RCS file: /cvsdev/mvl-kernel/linux/arch/x86_64/ia32/ptrace32.c,v
retrieving revision 1.1.36.1.8.3
diff -a -u -r1.1.36.1.8.3 ptrace32.c
--- arch/x86_64/ia32/ptrace32.c 19 Nov 2004 04:41:58 -0000 1.1.36.1.8.3
+++ arch/x86_64/ia32/ptrace32.c 5 Jan 2005 19:26:43 -0000
@@ -182,14 +182,14 @@
goto out;
*err = ptrace_check_attach(child, request == PTRACE_KILL);
if (*err < 0)
- goto out;
+ goto out;
return child;
- }

out:
- put_task_struct(child);
+ put_task_struct(child);
+ }
+
return NULL;
-
}

extern asmlinkage long sys_ptrace(long request, long pid, unsigned long addr, unsigned long data);