Hi,
On Fri, 2005-02-18 at 23:44 +0000, Mike Hearn wrote:
> On Fri, 2005-02-18 at 23:34 +0100, T.J. Zeeman wrote:
> > Warcraft still complains about the CD-rom being MIA though :( I'll see
> > if I can dig up a few hints from the log this weekend.
>
> Make sure your kernel hsa the ptrace regression fixes in.
I guess you meant the problems refered to in WWN250
(http://www.winehq.com/?issue=250). I checked and the patch there is
only for i386. I ported those to the x86_64 files (see attachments) and
tried again to no avail.
I also tried the test app as posted by Linus Torvalds here:
http://www.winehq.com/hypermail/wine-devel/2004/11/0551.html
When trying that on amd64 with the ptrace patches it does not even want
to compile (not completely surprising). In the chroot it segfaults.
A strace showed the following:
x5556c000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or
directory)
open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or
directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=32850, ...}) = 0
old_mmap(NULL, 32850, PROT_READ, MAP_PRIVATE, 3, 0) = 0x5556d000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or
directory)
open("/lib/tls/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\360Y\1"...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0644, st_size=1253924, ...}) = 0
old_mmap(NULL, 1260140, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) =
0x55576000
old_mmap(0x5569f000, 32768, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED,
3, 0x129000) = 0x5569f000
old_mmap(0x556a7000, 10860, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
MAP_ANONYMOUS, -1, 0) = 0x556a7000
close(3) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x556aa000
set_thread_area({entry_number:-1 -> 11, base_addr:0x556aa2a0,
limit:1048575, seg_32bit:1, contents:0, read_exec_only:0,
limit_in_pages:1, seg_not_present:0, useable:1}) = 0
munmap(0x5556d000, 32850) = 0
rt_sigaction(SIGTRAP, {0x8048438, [TRAP], SA_RESTART}, {SIG_DFL}, 8) = 0
mprotect(0x8048000, 4096, PROT_READ|PROT_WRITE) = 0
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
+++ killed by SIGSEGV +++
I haven't been this deep into low level code in a long time (and that
was 8086 asm simulated on a sparc), but I thought this would work and
not segfault. Anybody around here that can comment on that? Or should I
take this to another forum to further investigate? If so, where would
you suggest I take it?
regards,
Thomas
--- /usr/src/kernel-source-2.6.10/arch/x86_64/kernel/ptrace.c 2004-12-24 22:34:30.000000000 +0100
+++ ptrace.c 2005-03-01 20:32:29.713639136 +0100
@@ -79,6 +79,28 @@
return 0;
}
+static void set_singlestep(struct task_struct *child)
+{
+ long eflags;
+
+ set_tsk_thread_flag(child, TIF_SINGLESTEP);
+ eflags = get_stack_long(child, EFL_OFFSET);
+ put_stack_long(child, EFL_OFFSET, eflags | TRAP_FLAG);
+ child->ptrace |= PT_DTRACE;
+}
+
+static void clear_singlestep(struct task_struct *child)
+{
+ if (child->ptrace & PT_DTRACE) {
+ long eflags;
+
+ clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+ eflags = get_stack_long(child, EFL_OFFSET);
+ put_stack_long(child, EFL_OFFSET, eflags & ~TRAP_FLAG);
+ child->ptrace &= ~PT_DTRACE;
+ }
+}
+
/*
* Called by kernel/ptrace.c when detaching..
*
@@ -86,11 +108,12 @@
*/
void ptrace_disable(struct task_struct *child)
{
- long tmp;
+/* long tmp;
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET, tmp);
+ put_stack_long(child, EFL_OFFSET, tmp); */
+ clear_singlestep(child);
}
static int putreg(struct task_struct *child,
@@ -338,8 +361,6 @@
break;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: { /* restart after signal. */
- long tmp;
-
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
@@ -347,12 +368,9 @@
set_tsk_thread_flag(child,TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE);
- clear_tsk_thread_flag(child, TIF_SINGLESTEP);
child->exit_code = data;
/* make sure the single step bit is not set. */
- tmp = get_stack_long(child, EFL_OFFSET);
- tmp &= ~TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET,tmp);
+ clear_singlestep(child);
wake_up_process(child);
ret = 0;
break;
@@ -394,34 +412,23 @@
* exit.
*/
case PTRACE_KILL: {
- long tmp;
-
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
- tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET, tmp);
+ clear_singlestep(child);
wake_up_process(child);
break;
}
case PTRACE_SINGLESTEP: { /* set the trap flag. */
- long tmp;
-
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE);
- if ((child->ptrace & PT_DTRACE) == 0) {
- /* Spurious delayed TF traps may occur */
- child->ptrace |= PT_DTRACE;
- }
- tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET, tmp);
- set_tsk_thread_flag(child, TIF_SINGLESTEP);
+ set_singlestep(child);
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
--- /usr/src/kernel-source-2.6.10/arch/x86_64/kernel/signal.c 2004-12-24 22:35:23.000000000 +0100
+++ signal.c 2005-03-01 20:33:11.425298000 +0100
@@ -205,8 +205,14 @@
err |= __put_user(me->thread.trap_no, &sc->trapno);
err |= __put_user(me->thread.error_code, &sc->err);
err |= __put_user(regs->rip, &sc->rip);
+
+ /*
+ * Iff TF was set because the program is being single-stepped by a
+ * debugger, don't save that information on the signal stack.. We
+ * don't want debugging to change state.
+ */
eflags = regs->eflags;
- if (current->ptrace & PT_PTRACED) {
+ if (current->ptrace & PT_DTRACE) {
eflags &= ~TF_MASK;
}
err |= __put_user(eflags, &sc->eflags);
@@ -324,12 +330,16 @@
regs->rsp = (unsigned long)frame;
set_fs(USER_DS);
+ /*
+ * Clear TF when entering the signal handler, but
+ * notify any tracer that was single-stepping it.
+ * The tracer may want to single-step inside the
+ * handler too.
+ */
if (regs->eflags & TF_MASK) {
- if ((current->ptrace & (PT_PTRACED | PT_DTRACE)) == (PT_PTRACED | PT_DTRACE)) {
+ regs->eflags &= ~TF_MASK;
+ if (current->ptrace & PT_DTRACE)
ptrace_notify(SIGTRAP);
- } else {
- regs->eflags &= ~TF_MASK;
- }
}
#ifdef DEBUG_SIG
