Re: [PATCH 0/2] kallsyms: show typed function parameters in oops/WARN dumps

[Jiri Olsa]

On Mon, Mar 23, 2026 at 12:48:55PM -0400, Sasha Levin wrote:
> Building on the lineinfo series, this adds typed function parameter

hi,
could you please specify the exact tree/commit and point to the
series this patchset is based on?

thanks,
jirka


> display to oops and WARN dumps.  A build-time tool extracts parameter
> names and types from DWARF, and the kernel maps pt_regs to the calling
> convention at crash time.  When BTF is available, struct pointer
> parameters are dereferenced and their members displayed.
> 
> Example output from a WARN in a function receiving struct new_utsname *
> (kernel version info) and struct file * parameters:
> 
>  ------------[ cut here ]------------
>  WARNING: drivers/tty/sysrq.c:1209 at demo_crash+0xf/0x20 (drivers/tty/sysrq.c:1209)
>  CPU: 2 UID: 0 PID: 323 Comm: bash
>  RIP: 0010:demo_crash+0xf/0x20 (drivers/tty/sysrq.c:1209)
>  ...
>  RDI: ffffffffb8ca8d00
>  RSI: ffffa0a3c250acc0
>  ...
>  Function parameters (paraminfo_demo_crash):
>   uts      (struct new_utsname *) = 0xffffffffb8ca8d00
>    .sysname = "Linux"                        .nodename = "localhost"
>    .release = "7.0.0-rc2-00006-g3190..."     .version = "#45 SMP PRE"
>   file     (struct file *       ) = 0xffffa0a3c250acc0
>    .f_mode = (fmode_t)67993630               .f_op = (struct file_operations *)0xffffffffb7237620
>    .f_flags = (unsigned int)32769            .f_cred = (struct cred *)0xffffa0a3c2e06a80
>    .dentry = (struct dentry *)0xffffa0a3c0978cc0
>    .prev_pos = (loff_t)-1
>  Call Trace:
>   <TASK>
>   write_sysrq_trigger+0x96/0xb0 (drivers/tty/sysrq.c:1222)
>   proc_reg_write+0x54/0xa0 (fs/proc/inode.c:330)
>   vfs_write+0xc9/0x480 (fs/read_write.c:686)
>   ksys_write+0x6e/0xe0 (fs/read_write.c:738)
>   do_syscall_64+0xe2/0x570 (arch/x86/entry/syscall_64.c:62)
>   entry_SYSCALL_64_after_hwframe+0x77/0x7f (arch/x86/entry/entry_64.S:121)
> 
> Patch 1 adds the core paraminfo infrastructure (DWARF extraction,
> kernel-side lookup, register-to-parameter mapping, ~1-2 MB overhead).
> Patch 2 adds optional BTF-based struct rendering, gated behind
> CONFIG_KALLSYMS_PARAMINFO_BTF.
> 
> Sasha Levin (2):
>   kallsyms: show function parameter info in oops/WARN dumps
>   kallsyms: add BTF-based deep parameter rendering in oops dumps
> 
>  .../admin-guide/kallsyms-lineinfo.rst         |  31 +
>  arch/x86/kernel/dumpstack.c                   |   6 +-
>  include/linux/kallsyms.h                      |   9 +
>  init/Kconfig                                  |  40 ++
>  kernel/Makefile                               |   1 +
>  kernel/kallsyms.c                             | 182 ++++++
>  kernel/kallsyms_internal.h                    |   6 +
>  kernel/kallsyms_paraminfo_btf.c               | 199 ++++++
>  lib/Kconfig.debug                             |  11 +
>  lib/tests/Makefile                            |   3 +
>  lib/tests/paraminfo_kunit.c                   | 249 ++++++++
>  scripts/Makefile                              |   3 +
>  scripts/empty_paraminfo.S                     |  18 +
>  scripts/gen_paraminfo.c                       | 597 ++++++++++++++++++
>  scripts/link-vmlinux.sh                       |  44 +-
>  15 files changed, 1393 insertions(+), 6 deletions(-)
>  create mode 100644 kernel/kallsyms_paraminfo_btf.c
>  create mode 100644 lib/tests/paraminfo_kunit.c
>  create mode 100644 scripts/empty_paraminfo.S
>  create mode 100644 scripts/gen_paraminfo.c
> 
> --
> 2.51.0
> 
>