diff options
| author | Omar Sandoval <osandov@fb.com> | 2023-06-13 14:14:56 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-06-16 17:17:42 +0200 |
| commit | b9f174c811e3ae4ae8959dc57e6adb9990e913f4 (patch) | |
| tree | 3306ec83cfcfb8a59c8770d04e974469f3a2c6a6 /arch/x86/kernel | |
| parent | 858fd168a95c5b9669aac8db6c14a9aeab446375 (diff) | |
x86/unwind/orc: Add ELF section with ORC version identifier
Commits ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC
metadata") and fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in
two") changed the ORC format. Although ORC is internal to the kernel,
it's the only way for external tools to get reliable kernel stack traces
on x86-64. In particular, the drgn debugger [1] uses ORC for stack
unwinding, and these format changes broke it [2]. As the drgn
maintainer, I don't care how often or how much the kernel changes the
ORC format as long as I have a way to detect the change.
It suffices to store a version identifier in the vmlinux and kernel
module ELF files (to use when parsing ORC sections from ELF), and in
kernel memory (to use when parsing ORC from a core dump+symbol table).
Rather than hard-coding a version number that needs to be manually
bumped, Peterz suggested hashing the definitions from orc_types.h. If
there is a format change that isn't caught by this, the hashing script
can be updated.
This patch adds an .orc_header allocated ELF section containing the
20-byte hash to vmlinux and kernel modules, along with the corresponding
__start_orc_header and __stop_orc_header symbols in vmlinux.
1: https://github.com/osandov/drgn
2: https://github.com/osandov/drgn/issues/303
Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Fixes: fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lkml.kernel.org/r/aef9c8dc43915b886a8c48509a12ec1b006ca1ca.1686690801.git.osandov@osandov.com
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/unwind_orc.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 3ac50b7298d1..4d8e518365f4 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -7,6 +7,9 @@ #include <asm/unwind.h> #include <asm/orc_types.h> #include <asm/orc_lookup.h> +#include <asm/orc_header.h> + +ORC_HEADER; #define orc_warn(fmt, ...) \ printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__) |