Bug 206044
| Summary: | devel/gdb: Misc KGDB fixes | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Ports & Packages | Reporter: | John Baldwin <jhb> | ||||
| Component: | Individual Port(s) | Assignee: | John Baldwin <jhb> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Only Me | CC: | feld, koobs, luca.pizzamiglio, ports-secteam | ||||
| Priority: | --- | Keywords: | feature, patch | ||||
| Version: | Latest | Flags: | koobs:
maintainer-feedback+
koobs: merge-quarterly? |
||||
| Hardware: | Any | ||||||
| OS: | Any | ||||||
| Attachments: |
|
||||||
@John, would you like to assign yourself this issue for commit? I'd be happy to approve given relevant QA (poudriere, test suite if gdb has it, etc) Happy to commit it once Luca has reviewed it. There is no test suite for the kgdb bits of gdb, though I did test these changes by debugging a crashdump from a NULL function pointer panic (and had to fix kgdb to debug it). The other two patches I had tested previously as well (running kgdb against a kernel without debug symbols and checking 'info sharedlibrary' and using 'kgdb -n last'). Comment on attachment 165277 [details]
gdb_port_kgdb2.patch
Patch approved!
Thanks for the continuing support!
@John, this is good to proceed pending QA (portlint, poudriere) confirmation A commit references this bug: Author: jhb Date: Mon Jan 11 17:36:14 UTC 2016 New revision: 405792 URL: https://svnweb.freebsd.org/changeset/ports/405792 Log: Various fixes to kgdb. Port revision bumped since kgdb is enabled by default. - kgdb -n now permits any valid string to be used instead of only permitting numbers. In particular, this allows 'kgdb -n last' to be used to open the most recent vmcore. - kgdb will now try to determine the list of kernel modules even if the kernel binary does not include debug symbols. This works fine in kernels that have the changes in r290728. - Mark trapframes as "signal trampoline frames". GDB assumes that "normal" frames will never call into a NULL PC. Instead, it assumes that calling a NULL PC will result in an exception (and thus a signal being posted resulting in a signal frame). A trap for a NULL function pointer would thus stop unwinding once it hit the frame with a NULL PC. Marking the trapframes as a signal frame tells GDB it is ok to unwind past a NULL PC. One side effect is that frames in the asm handler now display as "signal handler called" instead of the raw line in assembly. Perhaps at some point it would be nice to mark these up the way ddb does with the trap number, etc. but GDB's stack code doesn't support custom frame printers. PR: 206044 Reviewed by: luca.pizzamiglio@gmail.com (maintainer) Approved by: koobs Changes: head/devel/gdb/Makefile head/devel/gdb/files/kgdb/amd64fbsd-kern.c head/devel/gdb/files/kgdb/fbsd-kld.c head/devel/gdb/files/kgdb/i386fbsd-kern.c head/devel/gdb/files/kgdb/kgdb-main.c head/devel/gdb/files/kgdb/ppcfbsd-kern.c head/devel/gdb/files/kgdb/sparc64fbsd-kern.c This bug can be closed now? Pending MFH 7.11 is already in the most recent quarterly and contains these changes. |
Created attachment 165277 [details] gdb_port_kgdb2.patch The enclosed patches fix three separate issues in kgdb and bump the portrevision (since KGDB is enabled by default): - kgdb -n now permits any valid string to be used instead of only permitting numbers. In particular, this allows 'kgdb -n last' to be used to open the most recent vmcore. - kgdb will now try to determine the list of kernel modules even if the kernel binary does not include debug symbols. This works fine in kernels that have the changes in r290728. - Mark trapframes as "signal trampoline frames". GDB assumes that "normal" frames will never call into a NULL PC. Instead, it assumes that calling a NULL PC will result in an exception (and thus a signal being posted resulting in a signal frame). A trap for a NULL function pointer would thus stop unwinding once it hit the frame with a NULL PC. Marking the trapframes as a signal frame tells GDB it is ok to unwind past a NULL PC. One side effect is that frames in the asm handler now display as "signal handler called" instead of the raw line in assembly. Perhaps at some point it would be nice to mark these up the way ddb does with the trap number, etc. but GDB's stack code doesn't support custom frame printers.