In the previous commit, we fixed crash's logic which determines the
module load addresses in the presence of sections with nonzero sh_addr.
This allowed GDB to correctly locate public variables (i.e. GLOBAL
symbols) via the ELF symbol table (msymbols). However, LOCAL symbols
still had incorrect addresses.
The root cause for those issues is not in crash. Instead, GDB does not
expect sections with nonzero sh_addr, and so it slipped up in multiple
places:
1. In default_symfile_offsets(), GDB detects the nonzero sh_addr field
and fails to apply the user-supplied section offsets. The result is
that later, in symfile_relocate_debug_section(), relocations are
applied to the DWARF info using the wrong section addresses, which
results in invalid addresses for variables. Clearly, this has
happened before, because crash has special-cased the "__ksymtab*"
section names to avoid this condition. To resolve this, we simply
drop the check for nonzero sh_addr altogether: the only ET_REL files
we encounter should be kernel modules, so there's no real reason to
be picky.
2. Even with that fixed, the user-supplied section addresses are
clobbered by the addr_info_make_relative(), which subtracts out
section offsets during its operation. To resolve this, undo the
operation for ET_REL files where a section address was provided by
the user (i.e. crash).
With these two fixes, both local and global variables from a module
section with nonzero sh_addr are correctly reported. Behavior is
unchanged for modules with a zero sh_addr.
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
The gdbserver is unused in crash-utility, but it
is always built by default during crash building.
Let's disable gdbserver building to save some time.
There are several advantages, for example:
[1] speed up crash building and save time
[2] avoid some compilation issues
[3] the following cross compile and ci will benefit
from this.
In addition, this is harmless for the old compilation
methods.
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
