create-diff-object: fixup new function handling

[sjenning]

The original logic in the inclusion tree code worked under the
assumption that it was the only code path marking symbols for inclusion.
Therefore, if the symbol had been marked as included, it could be safely
assumed that we also already called kpatch_include_symbol() on it. With
the special section handling marking symbols as included, however, this
assumption is not valid.

We should call kpatch_include_symbol() regardless of whether or not the
symbol has already been marked as included or not in order to possible
include the symbol's entire bundle.

Signed-off-by: Seth Jennings sjenning@redhat.com

[jpoimboe]

If I understand this right, does this mean we can remove the "rela->sym->include = 1" lines in kpatch_regenerate_special_section and kpatch_process_special_sections?

[sjenning]

My brain is about done for today. I don't think that is right since there could be some symbols in the rela group that are not reachable from a changed function, but are still need for the rela group to resolve.

Just for kicks I did remove the include line from kpatch_regenerate_special_section() and it fail integration. Don't know why. Logs didn't say.

[jpoimboe]

Ok, I think that makes sense.

[jpoimboe]

Getting an integration test failure due to a create-diff-object seg fault. Looks like infinite recursion:

Core was generated by `/home/jpoimboe/git/kpatch/kpatch-build/create-diff-object orig/net/core/dev.o p'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000000403f06 in kpatch_include_symbol (sym=<error reading variable: Cannot access memory at address 0x7fffea841ff8>, 
    recurselevel=<error reading variable: Cannot access memory at address 0x7fffea841ff4>) at create-diff-object.c:939
939 {
Missing separate debuginfos, use: debuginfo-install elfutils-libelf-0.158-3.fc20.x86_64
(gdb) bt
#0  0x0000000000403f06 in kpatch_include_symbol (sym=<error reading variable: Cannot access memory at address 0x7fffea841ff8>, 
    recurselevel=<error reading variable: Cannot access memory at address 0x7fffea841ff4>) at create-diff-object.c:939
#1  0x00000000004040d6 in kpatch_include_symbol (sym=0x1c9c930, recurselevel=130973) at create-diff-object.c:965
#2  0x00000000004040d6 in kpatch_include_symbol (sym=0x1c9c930, recurselevel=130972) at create-diff-object.c:965
#3  0x00000000004040d6 in kpatch_include_symbol (sym=0x1c9c930, recurselevel=130971) at create-diff-object.c:965
....
(gdb) p *sym
$8 = {list = {next = 0x1c9c990, prev = 0x1c9c8d0}, twin = 0x1a2ad60, sec = 0x1c75630, sym = {st_name = 6637, st_info = 18 '\022', st_other = 0 '\000', st_shndx = 83, 
    st_value = 0, st_size = 153}, name = 0x7fd0341a49f5 <error: Cannot access memory at address 0x7fd0341a49f5>, index = 647, bind = 1 '\001', type = 2 '\002', 
  status = CHANGED, {include = 1, strip = 1}}
(gdb) p *sym->sec
$12 = {list = {next = 0x1c756d0, prev = 0x1c75590}, twin = 0x1a03a60, sh = {sh_name = 1321, sh_type = 1, sh_flags = 6, sh_addr = 0, sh_offset = 7712, sh_size = 153, 
    sh_link = 0, sh_info = 0, sh_addralign = 16, sh_entsize = 0}, data = 0x1c56860, name = 0x7fd03418f7c9 <error: Cannot access memory at address 0x7fd03418f7c9>, index = 83, 
  status = CHANGED, include = 1, {{base = 0x1c756d0, relas = {next = 0x1c8ea70, prev = 0x1c9c930}}, {rela = 0x1c756d0, secsym = 0x1c8ea70, sym = 0x1c9c930}}}

[sjenning]

I knew I had that check in there for some reason!
On Jun 26, 2014 10:03 PM, "Josh Poimboeuf" notifications@github.com wrote:

Getting an integration test failure due to a create-diff-object seg fault.
Looks like infinite recursion:

Core was generated by `/home/jpoimboe/git/kpatch/kpatch-build/create-diff-object orig/net/core/dev.o p'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x0000000000403f06 in kpatch_include_symbol (sym=<error reading variable: Cannot access memory at address 0x7fffea841ff8>,
recurselevel=<error reading variable: Cannot access memory at address 0x7fffea841ff4>) at create-diff-object.c:939
939 {
Missing separate debuginfos, use: debuginfo-install elfutils-libelf-0.158-3.fc20.x86_64
(gdb) bt
#0 0x0000000000403f06 in kpatch_include_symbol (sym=<error reading variable: Cannot access memory at address 0x7fffea841ff8>,
recurselevel=<error reading variable: Cannot access memory at address 0x7fffea841ff4>) at create-diff-object.c:939
#1 0x00000000004040d6 in kpatch_include_symbol (sym=0x1c9c930, recurselevel=130973) at create-diff-object.c:965
#2 0x00000000004040d6 in kpatch_include_symbol (sym=0x1c9c930, recurselevel=130972) at create-diff-object.c:965
#3 0x00000000004040d6 in kpatch_include_symbol (sym=0x1c9c930, recurselevel=130971) at create-diff-object.c:965
....
(gdb) p *sym
$8 = {list = {next = 0x1c9c990, prev = 0x1c9c8d0}, twin = 0x1a2ad60, sec = 0x1c75630, sym = {st_name = 6637, st_info = 18 '\022', st_other = 0 '\000', st_shndx = 83,
st_value = 0, st_size = 153}, name = 0x7fd0341a49f5 <error: Cannot access memory at address 0x7fd0341a49f5>, index = 647, bind = 1 '\001', type = 2 '\002',
status = CHANGED, {include = 1, strip = 1}}
(gdb) p *sym->sec
$12 = {list = {next = 0x1c756d0, prev = 0x1c75590}, twin = 0x1a03a60, sh = {sh_name = 1321, sh_type = 1, sh_flags = 6, sh_addr = 0, sh_offset = 7712, sh_size = 153,
sh_link = 0, sh_info = 0, sh_addralign = 16, sh_entsize = 0}, data = 0x1c56860, name = 0x7fd03418f7c9 <error: Cannot access memory at address 0x7fd03418f7c9>, index = 83,
status = CHANGED, include = 1, {{base = 0x1c756d0, relas = {next = 0x1c8ea70, prev = 0x1c9c930}}, {rela = 0x1c756d0, secsym = 0x1c8ea70, sym = 0x1c9c930}}}

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