On Wed, Nov 15, 2006 at 10:05:35AM -0500, Dave Anderson wrote:
>
> Hi Rachita,
>
> Great -- I'll tinker with this today and get out a new release ASAP.
>
> One question re: this hanging thread:
>
> > > So, in other words, if we hardwire the user_regs_struct so that
> > > it uses the NT_PRSTATUS registers all the time, then we get
> > > the second (preferred/better) budget back trace when unwind
> > > is off.
> > >
> > > That being the case, I argue for hardwiring them all the time.
> >
> > Yes, we can(should) do that for all the active tasks.
> >
> > Rachita
> >
>
> Correct me if I'm wrong here, but...
>
> If, during machdep_init(POST_GBD), if we force-initialize
> (hardwire when necessary) the relevant user_regs_struct items,
Hi Dave
Yes, this should serve the purpose.
Thanks
Rachita
> then we could change this line from:
>
> if (((NETDUMP_DUMPFILE() || KDUMP_DUMPFILE()) &&
> VALID_STRUCT(user_regs_struct) && (bt->task == tt->panic_task)) ||
> (KDUMP_DUMPFILE() && (kt->flags & DWARF_UNWIND) &&
> (bt->flags & BT_DUMPFILE_SEARCH))) {
> to:
>
> if (((NETDUMP_DUMPFILE() || KDUMP_DUMPFILE()) &&
> VALID_STRUCT(user_regs_struct) && (bt->task == tt->panic_task)) ||
> (KDUMP_DUMPFILE() && (bt->flags & BT_DUMPFILE_SEARCH))) {
>
> To be absolutely safe in a backwards-compatibility sense, perhaps
> we should only do the hardwiring if it's a KDUMP_DUMPFILE().
> Make sense?
>
> Dave
>
>
>
>
>
>
> >
> >
> > defs.h | 3
> > unwind_x86_32_64.c | 77 ++++++++++++++++++++++---
> > x86_64.c | 163 ++++++-----------------------------------------------
> > 3 files changed, 91 insertions(+), 152 deletions(-)
> >
> > diff -puN x86_64.c~cfi_backtrace_minor_fixes x86_64.c
> > --- crash-4.0-3.9/x86_64.c~cfi_backtrace_minor_fixes 2006-11-15 18:29:04.848359480 +0530
> > +++ crash-4.0-3.9-rachita/x86_64.c 2006-11-15 19:00:40.687148176 +0530
> > @@ -2548,6 +2548,7 @@ x86_64_dwarf_back_trace_cmd(struct bt_in
> > irq_eframe = 0;
> > last_process_stack_eframe = 0;
> > bt->call_target = NULL;
> > + bt->bptr = 0;
> > rsp = bt->stkptr;
> > if (!rsp) {
> > error(INFO, "cannot determine starting stack pointer\n");
> > @@ -2617,31 +2618,9 @@ in_exception_stack:
> >
> > stacktop = bt->stacktop - SIZE(pt_regs);
> >
> > - if ((kt->flags & DWARF_UNWIND) && !done)
> > - done = dwarf_backtrace(bt, stacktop);
> > -
> > - for (i = (rsp - bt->stackbase)/sizeof(ulong);
> > - !done && (rsp < stacktop); i++, rsp += sizeof(ulong)) {
> > -
> > - up = (ulong *)(&bt->stackbuf[i*sizeof(ulong)]);
> > -
> > - if (!is_kernel_text(*up))
> > - continue;
> > -
> > - switch (x86_64_print_stack_entry(bt, ofp, level, i,*up))
> > - {
> > - case BACKTRACE_ENTRY_AND_EFRAME_DISPLAYED:
> > - rsp += SIZE(pt_regs);
> > - i += SIZE(pt_regs)/sizeof(ulong);
> > - case BACKTRACE_ENTRY_DISPLAYED:
> > - level++;
> > - break;
> > - case BACKTRACE_ENTRY_IGNORED:
> > - break;
> > - case BACKTRACE_COMPLETE:
> > - done = TRUE;
> > - break;
> > - }
> > + if ((kt->flags & DWARF_UNWIND) && !done) {
> > + level = dwarf_backtrace(bt, level, stacktop);
> > + done = TRUE;
> > }
> >
> > cs = x86_64_exception_frame(EFRAME_PRINT|EFRAME_CS, 0,
> > @@ -2702,32 +2681,10 @@ in_exception_stack:
> >
> > stacktop = bt->stacktop - 64; /* from kernel code */
> >
> > - if ((kt->flags & DWARF_UNWIND) && !done)
> > - done = dwarf_backtrace(bt, stacktop);
> > -
> > - for (i = (rsp - bt->stackbase)/sizeof(ulong);
> > - !done && (rsp < stacktop); i++, rsp += sizeof(ulong)) {
> > -
> > - up = (ulong *)(&bt->stackbuf[i*sizeof(ulong)]);
> > -
> > - if (!is_kernel_text(*up))
> > - continue;
> > -
> > - switch (x86_64_print_stack_entry(bt, ofp, level, i,*up))
> > - {
> > - case BACKTRACE_ENTRY_AND_EFRAME_DISPLAYED:
> > - rsp += SIZE(pt_regs);
> > - i += SIZE(pt_regs)/sizeof(ulong);
> > - case BACKTRACE_ENTRY_DISPLAYED:
> > - level++;
> > - break;
> > - case BACKTRACE_ENTRY_IGNORED:
> > - break;
> > - case BACKTRACE_COMPLETE:
> > - done = TRUE;
> > - break;
> > - }
> > - }
> > + if ((kt->flags & DWARF_UNWIND) && !done) {
> > + level = dwarf_backtrace(bt, level, stacktop);
> > + done = TRUE;
> > + }
> >
> > if (!BT_REFERENCE_CHECK(bt))
> > fprintf(fp, "--- <IRQ stack> ---\n");
> > @@ -2792,21 +2749,6 @@ in_exception_stack:
> > }
> >
> > /*
> > - * For a normally blocked task, hand-create the first level.
> > - */
> > - if (!done && !(kt->flags & DWARF_UNWIND) &&
> > - !(bt->flags & (BT_TEXT_SYMBOLS|BT_EXCEPTION_STACK|BT_IRQSTACK)) &&
> > - STREQ(closest_symbol(bt->instptr), "thread_return")) {
> > - bt->flags |= BT_SCHEDULE;
> > - i = (rsp - bt->stackbase)/sizeof(ulong);
> > - x86_64_print_stack_entry(bt, ofp, level,
> > - i, bt->instptr);
> > - bt->flags &= ~(ulonglong)BT_SCHEDULE;
> > - rsp += sizeof(ulong);
> > - level++;
> > - }
> > -
> > - /*
> > * Dump the IRQ exception frame from the process stack.
> > * If the CS register indicates a user exception frame,
> > * then set done to TRUE to avoid the process stack walk-through.
> > @@ -2814,8 +2756,7 @@ in_exception_stack:
> > */
> > if (irq_eframe) {
> > bt->flags |= BT_EXCEPTION_FRAME;
> > - i = (irq_eframe - bt->stackbase)/sizeof(ulong);
> > - x86_64_print_stack_entry(bt, ofp, level, i, bt->instptr);
> > + level = dwarf_print_stack_entry(bt, level);
> > bt->flags &= ~(ulonglong)BT_EXCEPTION_FRAME;
> > cs = x86_64_exception_frame(EFRAME_PRINT|EFRAME_CS, 0,
> > bt->stackbuf + (irq_eframe - bt->stackbase), bt, ofp);
> > @@ -2833,81 +2774,10 @@ in_exception_stack:
> > /*
> > * Walk the process stack.
> > */
> > - if ((kt->flags & DWARF_UNWIND) && !done)
> > - done = dwarf_backtrace(bt, bt->stacktop);
> > -
> > - for (i = (rsp - bt->stackbase)/sizeof(ulong);
> > - !done && (rsp < bt->stacktop); i++, rsp += sizeof(ulong)) {
> > -
> > - up = (ulong *)(&bt->stackbuf[i*sizeof(ulong)]);
> > -
> > - if (!is_kernel_text(*up))
> > - continue;
> > -
> > - if ((bt->flags & BT_CHECK_CALLER)) {
> > - /*
> > - * A non-zero offset value from the value_search()
> > - * lets us know if it's a real text return address.
> > - */
> > - spt = value_search(*up, &offset);
> > - /*
> > - * sp gets the syment of the function that the text
> > - * routine above called before leaving its return
> > - * address on the stack -- if it can be determined.
> > - */
> > - sp = x86_64_function_called_by((*up)-5);
> > -
> > - if (sp == NULL) {
> > - /*
> > - * We were unable to get the called function.
> > - * If the text address had an offset, then
> > - * it must have made an indirect call, and
> > - * can't have called our target function.
> > - */
> > - if (offset) {
> > - if (CRASHDEBUG(1))
> > - fprintf(ofp,
> > - "< ignoring %s() -- makes indirect call and NOT %s()>\n",
> > - spt->name,
> > - bt->call_target);
> > - continue;
> > - }
> > - } else if ((machdep->flags & SCHED_TEXT) &&
> > - STREQ(bt->call_target, "schedule") &&
> > - STREQ(sp->name, "__sched_text_start")) {
> > - ; /* bait and switch */
> > - } else if (!STREQ(sp->name, bt->call_target)) {
> > - /*
> > - * We got function called by the text routine,
> > - * but it's not our target function.
> > - */
> > - if (CRASHDEBUG(2))
> > - fprintf(ofp,
> > - "< ignoring %s() -- calls %s() and NOT %s()>\n",
> > - spt->name, sp->name,
> > - bt->call_target);
> > - continue;
> > - }
> > - }
> > -
> > - switch (x86_64_print_stack_entry(bt, ofp, level, i,*up))
> > - {
> > - case BACKTRACE_ENTRY_AND_EFRAME_DISPLAYED:
> > - last_process_stack_eframe = rsp + 8;
> > - if (x86_64_print_eframe_location(last_process_stack_eframe, level, ofp))
> > - level++;
> > - rsp += SIZE(pt_regs);
> > - i += SIZE(pt_regs)/sizeof(ulong);
> > - case BACKTRACE_ENTRY_DISPLAYED:
> > - level++;
> > - break;
> > - case BACKTRACE_ENTRY_IGNORED:
> > - break;
> > - case BACKTRACE_COMPLETE:
> > - done = TRUE;
> > - break;
> > - }
> > - }
> > + if ((kt->flags & DWARF_UNWIND) && !done) {
> > + level = dwarf_backtrace(bt, level, bt->stacktop);
> > + done = TRUE;
> > + }
> >
> > if (!irq_eframe && !is_kernel_thread(bt->tc->task) &&
> > (GET_STACKBASE(bt->tc->task) == bt->stackbase)) {
> > @@ -3193,6 +3063,13 @@ x86_64_exception_frame(ulong flags, ulon
> > x86_64_do_bt_reference_check(bt, r15, NULL);
> > }
> >
> > + /* Remember the rip and rsp for unwinding the process stack */
> > + if (kt->flags & DWARF_UNWIND){
> > + bt->instptr = rip;
> > + bt->stkptr = rsp;
> > + bt->bptr = rbp;
> > + }
> > +
> > if (kvaddr)
> > FREEBUF(pt_regs_buf);
> >
> > diff -puN unwind_x86_32_64.c~cfi_backtrace_minor_fixes unwind_x86_32_64.c
> > --- crash-4.0-3.9/unwind_x86_32_64.c~cfi_backtrace_minor_fixes 2006-11-15 18:35:50.519688064 +0530
> > +++ crash-4.0-3.9-rachita/unwind_x86_32_64.c 2006-11-15 19:31:45.705622272 +0530
> > @@ -1036,9 +1036,8 @@ dump_local_unwind_tables(void)
> >
> >
> > int
> > -dwarf_backtrace(struct bt_info *bt, ulong stacktop)
> > +dwarf_backtrace(struct bt_info *bt, int level, ulong stacktop)
> > {
> > - int n = 0;
> > unsigned long bp, offset;
> > struct syment *sp;
> > char *name;
> > @@ -1051,7 +1050,7 @@ dwarf_backtrace(struct bt_info *bt, ulon
> > UNW_PC(frame) = bt->instptr;
> >
> > /* read rbp from stack for non active tasks */
> > - if (!(bt->flags & BT_DUMPFILE_SEARCH) ) {
> > + if (!(bt->flags & BT_DUMPFILE_SEARCH) && !bt->bptr) {
> > // readmem(frame->regs.rsp, KVADDR, &bp,
> > readmem(UNW_SP(frame), KVADDR, &bp,
> > sizeof(unsigned long), "reading bp", FAULT_ON_ERROR);
> > @@ -1084,7 +1083,7 @@ dwarf_backtrace(struct bt_info *bt, ulon
> >
> >
> > name = sp->name;
> > - fprintf(fp, " #0 [%016lx] %s at %016lx \n", UNW_SP(frame), name, UNW_PC(frame));
> > + fprintf(fp, " #%d [%016lx] %s at %016lx \n", level, UNW_SP(frame), name, UNW_PC(frame));
> >
> > if (CRASHDEBUG(2))
> > fprintf(fp, " < SP: %lx PC: %lx FP: %lx >\n", UNW_SP(frame),
> > @@ -1092,7 +1091,12 @@ dwarf_backtrace(struct bt_info *bt, ulon
> >
> > while ((UNW_SP(frame) < stacktop)
> > && !unwind(frame) && UNW_PC(frame)) {
> > - n++;
> > + /* To prevent rip pushed on IRQ stack being reported both
> > + * both on the IRQ and process stacks
> > + */
> > + if ((bt->flags & BT_IRQSTACK) && (UNW_SP(frame) >= stacktop - 16))
> > + break;
> > + level++;
> > sp = value_search(UNW_PC(frame), &offset);
> > if (!sp) {
> > if (CRASHDEBUG(1))
> > @@ -1101,9 +1105,24 @@ dwarf_backtrace(struct bt_info *bt, ulon
> > UNW_PC(frame));
> > break;
> > }
> > +
> > + /*
> > + * If offset is zero, it means we have crossed over to the next
> > + * function. Recalculate by adjusting the text address
> > + */
> > + if (!offset) {
> > + sp = value_search(UNW_PC(frame) - 1, &offset);
> > + if (!sp) {
> > + if (CRASHDEBUG(1))
> > + fprintf(fp,
> > + "unwind: cannot find symbol for PC: %lx\n",
> > + UNW_PC(frame)-1);
> > + goto bailout;
> > + }
> > + }
> > name = sp->name;
> > - fprintf(fp, "%s#%d [%016lx] %s at %016lx \n", n < 10 ? " " : "",
> > - n, UNW_SP(frame), name, UNW_PC(frame));
> > + fprintf(fp, "%s#%d [%016lx] %s at %016lx \n", level < 10 ? " " : "",
> > + level, UNW_SP(frame), name, UNW_PC(frame));
> >
> > if (CRASHDEBUG(2))
> > fprintf(fp, " < SP: %lx PC: %lx FP: %lx >\n", UNW_SP(frame),
> > @@ -1112,7 +1131,49 @@ dwarf_backtrace(struct bt_info *bt, ulon
> >
> > bailout:
> > FREEBUF(frame);
> > - return TRUE;
> > + return ++level;
> > +}
> > +
> > +int dwarf_print_stack_entry(struct bt_info *bt, int level)
> > +{
> > + int n = 0;
> > + unsigned long offset;
> > + struct syment *sp;
> > + char *name;
> > + struct unwind_frame_info *frame;
> > +
> > + frame = (struct unwind_frame_info *)GETBUF(sizeof(struct unwind_frame_info));
> > + UNW_SP(frame) = bt->stkptr;
> > + UNW_PC(frame) = bt->instptr;
> > +
> > + sp = value_search(UNW_PC(frame), &offset);
> > + if (!sp) {
> > + if (CRASHDEBUG(1))
> > + fprintf(fp, "unwind: cannot find symbol for PC: %lx\n",
> > + UNW_PC(frame));
> > + goto bailout;
> > + }
> > +
> > + /*
> > + * If offset is zero, it means we have crossed over to the next
> > + * function. Recalculate by adjusting the text address
> > + */
> > + if (!offset) {
> > + sp = value_search(UNW_PC(frame) - 1, &offset);
> > + if (!sp) {
> > + if (CRASHDEBUG(1))
> > + fprintf(fp,
> > + "unwind: cannot find symbol for PC: %lx\n",
> > + UNW_PC(frame)-1);
> > + goto bailout;
> > + }
> > + }
> > + name = sp->name;
> > + fprintf(fp, " #%d [%016lx] %s at %016lx \n", level, UNW_SP(frame), name, UNW_PC(frame));
> > +
> > +bailout:
> > + FREEBUF(frame);
> > + return level;
> > }
> >
> > void
> > diff -puN defs.h~cfi_backtrace_minor_fixes defs.h
> > --- crash-4.0-3.9/defs.h~cfi_backtrace_minor_fixes 2006-11-15 18:51:28.030164808 +0530
> > +++ crash-4.0-3.9-rachita/defs.h 2006-11-15 18:51:46.272391568 +0530
> > @@ -645,6 +645,7 @@ struct bt_info {
> > ulonglong flags;
> > ulong instptr;
> > ulong stkptr;
> > + ulong bptr;
> > ulong stackbase;
> > ulong stacktop;
> > char *stackbuf;
> > @@ -3626,7 +3627,7 @@ struct machine_specific {
> > * unwind_x86_32_64.c
> > */
> > void init_unwind_table(void);
> > -int dwarf_backtrace(struct bt_info *, ulong);
> > +int dwarf_backtrace(struct bt_info *, int, ulong);
> > void dwarf_debug(struct bt_info *);
> >
> > #endif
> > _
--
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