This patch adds some sanity checks to keep register and memory stack
pointers in the unw_frame_info structure within the tasks stack address
range.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Minor problem for mainstream. Big problem for checkpoint/restore,
because all the stopped/traced processes are born in this state,
hence they cannot be checkpointed again due to failing unwind.
The problem was identified as assumption in kernel unwind library
that top level frame is different of syscall frame. It is the case
unless process was born with CLONE_STOPPED.
Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-Off-By: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Delete the special case unwind code that was only used by the old
MCA/INIT handler.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
unwind.c can read the wrong unat bits from switch_stack.
sw->caller_unat is the value of ar.unat when the task was blocked.
sw->ar_unat is the value of ar.unat after doing st8.spill for r4-7.
IOW, ar_unat is caller_unat with 4 bits changed.
unw_access_gr() uses sw->ar_unat for r4-7 (correct), but it also uses
sw->ar_unat for other scratch registers (incorrect). sw->ar_unat
should only be used for r4-7, everything else should use
sw->caller_unat, unless modified by unwind info. Using sw->ar_unat
risks picking up the 4 bits that were overwritten when r4-7 were saved.
Also this line is wrong
unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_UNAT);
and should be
unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_PFS);
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Detect user space by the unwind frame with predicate PRED_USER_STACK
set, instead of a user space IP. Tighten up the last ditch check for
running off the top of the kernel stack.
Based on a suggestion by David Mosberger, reworked to fit the current
tree. This survives my stress test which used to break 2.6.9 kernels.
Unlike 2.6.11, the stress test now unwinds to the correct point, so
gdb can get the user space registers.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
