On 1/27/25 1:33 PM, Weinan Liu wrote:
This patchset implements a generic kernel sframe-based [1] unwinder.
The main goal is to support reliable stacktraces on arm64.
On x86 orc unwinder provides reliable stacktraces. But arm64 misses the
required support from objtool: it cannot generate orc unwind tables for
arm64.
Currently, there's already a sframe unwinder proposed for userspace: [2].
Since the sframe unwind table algorithm is similar, these two proposal
could integrate common functionality in the future.
There are some incomplete features or challenges:
- The unwinder doesn't yet work with kernel modules. The `start_addr` of
FRE from kernel modules doesn't appear correct, preventing us from
unwinding functions from kernel modules.
I did file https://sourceware.org/bugzilla/show_bug.cgi?id=32589
earlier. It is misleading (and inconvenient) to see all 0s in the dump
of non-relocated SFrame section.
I get the sense that while issue 32589 may be causing confusion that the
SFrame data is not correct, the problem is elsewhere ?
I can share a fix for 32589 so atleast we can verify that the starting
point is sane.
- Currently, only GCC supports sframe.
Ref:
[1]: https://sourceware.org/binutils/docs/sframe-spec.html
[2]: https://lore.kernel.org/lkml/cover.1730150953.git.jpoimboe@xxxxxxxxxx/
Madhavan T. Venkataraman (1):
arm64: Define TIF_PATCH_PENDING for livepatch
Weinan Liu (7):
unwind: build kernel with sframe info
arm64: entry: add unwind info for various kernel entries
unwind: add sframe v2 header
unwind: Implement generic sframe unwinder library
unwind: arm64: Add sframe unwinder on arm64
unwind: arm64: add reliable stacktrace support for arm64
arm64: Enable livepatch for ARM64
Makefile | 6 +
arch/Kconfig | 8 +
arch/arm64/Kconfig | 3 +
arch/arm64/Kconfig.debug | 10 +
arch/arm64/include/asm/stacktrace/common.h | 6 +
arch/arm64/include/asm/thread_info.h | 4 +-
arch/arm64/kernel/entry-common.c | 4 +
arch/arm64/kernel/entry.S | 10 +
arch/arm64/kernel/setup.c | 2 +
arch/arm64/kernel/stacktrace.c | 102 ++++++++++
include/asm-generic/vmlinux.lds.h | 12 ++
include/linux/sframe_lookup.h | 43 +++++
kernel/Makefile | 1 +
kernel/sframe.h | 215 +++++++++++++++++++++
kernel/sframe_lookup.c | 196 +++++++++++++++++++
15 files changed, 621 insertions(+), 1 deletion(-)
create mode 100644 include/linux/sframe_lookup.h
create mode 100644 kernel/sframe.h
create mode 100644 kernel/sframe_lookup.c
