Hi Fuli,
On Thu, Feb 12, 2026 at 6:57 PM Fuli Qi (Fujitsu) <qi.fuli(a)fujitsu.com> wrote:
Hello Tao Liu,
Thank you for the review.
Could you please kindly proceed with merging this patch?
Best,
Fuli
> -----Original Message-----
> From: Tao Liu <ltao(a)redhat.com>
> Sent: Tuesday, December 30, 2025 1:32 PM
> To: Motomasa Suzuki <moto0123moto(a)gmail.com>
> Cc: devel(a)lists.crash-utility.osci.io; Qi, Fuli/斉 福利 <qi.fuli(a)fujitsu.com>
> Subject: Re: [PATCH v2] sys: Display livepatch transition status in KERNEL line
>
> [You don't often get email from ltao(a)redhat.com. Learn why this is important at
>
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>
> On Tue, Dec 23, 2025 at 6:51 PM Motomasa Suzuki
> <moto0123moto(a)gmail.com> wrote:
> >
> > This commit enhances the 'sys' command to show if a kernel livepatch
> > is currently in a transition phase, directly within the KERNEL output line.
> >
> > Currently, diagnosing system state during or immediately after
> > livepatch operations can be ambiguous. While 'livepatch' is indicated
> > by '[LIVEPATCH]', there's no direct indicator within
'crash' itself to
> > show if a livepatch is actively applying, reverting, or in some other
> > transient state. This lack of immediate visibility can complicate
> > crash analysis, as the system might be in an inconsistent state due to
> > an ongoing patch application/reversion.
> >
> > This change introduces a new '[TRANSITION]' flag which appears next to
> > '[LIVEPATCH]' and '[TAINTED]' in the 'sys' command
output. This flag
> > is set if the livepatch subsystem indicates an in-progress transition
> > (e.g., as exposed via
'/sys/kernel/livepatch/<patch_name>/transition').
> >
> > Example 'sys' output with this change:
> > KERNEL: /usr/lib/debug/lib/modules/<version_name>/vmlinux
> > [LIVEPATCH] [TRANSITION] [TAINTED]
> >
> > This enhancement provides critical, at-a-glance information for
> > developers and administrators, allowing them to quickly ascertain if
> > ongoing livepatch activity might be influencing a system's behavior
> > during crash investigations. It directly leverages existing kernel
> > livepatch status infrastructure to enrich the crash utility's
> > diagnostic capabilities.
> >
> >
> > Changes v1 -> v2:
> > - Reworked klp_patches list traversal to use the crash utility’s
> > do_list() helper instead of manual list handling.
>
> The v2 LGTM, so ack.
>
> Thanks,
> Tao Liu
> >
> > Signed-off-by: Motomasa Suzuki <moto0123moto(a)gmail.com>
> > ---
> > defs.h | 1 +
> > kernel.c | 75
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> +++--
> > 2 files changed, 74 insertions(+), 2 deletions(-)
> >
> > diff --git a/defs.h b/defs.h
> > index ceed3a9..cfdfa08 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -2289,6 +2289,7 @@ struct offset_table { /* stash of
> commonly-used offsets */
> > long bpf_ringbuf_consumer_pos;
> > long bpf_ringbuf_nr_pages;
> > long hrtimer_clock_base_index;
> > + long klp_patch_list;
> > };
> >
> > struct size_table { /* stash of commonly-used sizes */
> > diff --git a/kernel.c b/kernel.c
> > index bb148d0..ccc4b3d 100644
> > --- a/kernel.c
> > +++ b/kernel.c
> > @@ -464,6 +464,11 @@ kernel_init()
> > "list_head.next offset: %ld: list command may
fail\n",
> > OFFSET(list_head_next));
> >
> > + if (STRUCT_EXISTS("klp_patch")) {
> > + if (MEMBER_EXISTS("klp_patch", "list"))
> > + MEMBER_OFFSET_INIT(klp_patch_list,
"klp_patch",
> "list");
> > + }
> > +
> > MEMBER_OFFSET_INIT(hlist_node_next, "hlist_node",
"next");
> > MEMBER_OFFSET_INIT(hlist_node_pprev, "hlist_node",
"pprev");
> > STRUCT_SIZE_INIT(hlist_head, "hlist_head"); @@ -5689,6
> > +5694,70 @@ is_livepatch(void)
> > return FALSE;
> > }
> >
> > +struct klp_transition_ctx {
> > + ulong transition_patch;
> > + int found;
> > +};
> > +
> > +static int
> > +klp_transition_match(void *entry, void *data) {
> > + struct klp_transition_ctx *ctx = data;
> > +
> > + if ((ulong)entry == ctx->transition_patch) {
> > + ctx->found = TRUE;
> > + return TRUE;
> > + }
> > +
> > + return FALSE;
> > +}
> > +
> > +static int
> > +is_livepatch_transition(void)
> > +{
> > + struct kernel_list_head head;
> > + struct list_data ld;
> > + struct klp_transition_ctx ctx;
> > + ulong transition_patch;
> > + ulong list_addr;
> > + int ret;
> > +
> > + if (!try_get_symbol_data("klp_transition_patch",
> > + sizeof(ulong), &transition_patch) || !transition_patch)
> > + return FALSE;
> > +
> > + if (!STRUCT_EXISTS("klp_patch")
> || !VALID_MEMBER(klp_patch_list) ||
> > + !kernel_symbol_exists("klp_patches"))
> > + return TRUE;
> > +
> > + list_addr = symbol_value("klp_patches");
> > + if (!readmem(list_addr, KVADDR, &head, sizeof(head),
"klp_patches",
> > + RETURN_ON_ERROR | QUIET))
> > + return TRUE;
> > +
> > + if (!head.next || head.next == (void *)list_addr)
> > + return TRUE;
> > +
> > + BZERO(&ctx, sizeof(ctx));
> > + ctx.transition_patch = transition_patch;
> > +
> > + BZERO(&ld, sizeof(ld));
> > + ld.flags =
> LIST_CALLBACK|CALLBACK_RETURN|RETURN_ON_LIST_ERROR|
> > + RETURN_ON_DUPLICATE|LIST_ALLOCATE;
> > + ld.start = (ulong)head.next;
> > + ld.end = list_addr;
> > + ld.member_offset = OFFSET(list_head_next);
> > + ld.list_head_offset = OFFSET(klp_patch_list);
> > + ld.callback_func = klp_transition_match;
> > + ld.callback_data = &ctx;
> > +
> > + ret = do_list(&ld);
> > + if (ret < 0)
> > + return FALSE;
> > +
> > + return ctx.found;
> > +}
> > +
> > /*
> > * Display system stats at init-time or for the sys command.
> > */
> > @@ -5732,17 +5801,19 @@ display_sys_stats(void)
> > }
> > } else {
> > if (pc->system_map) {
> > - fprintf(fp, " SYSTEM MAP: %s%s%s\n",
> pc->system_map,
> > + fprintf(fp, " SYSTEM MAP: %s%s%s%s\n",
> > + pc->system_map,
> > is_livepatch() ? " [LIVEPATCH]" :
"",
> > + is_livepatch_transition() ? "
> > + [TRANSITION]" : "",
> > is_kernel_tainted() ? " [TAINTED]" :
"");
> > fprintf(fp, "DEBUG KERNEL: %s %s\n",
> > pc->namelist_orig ?
> > pc->namelist_orig :
pc->namelist,
> >
> debug_kernel_version(pc->namelist));
> > } else
> > - fprintf(fp, " KERNEL: %s%s%s\n",
> pc->namelist_orig ?
> > + fprintf(fp, " KERNEL: %s%s%s%s\n",
> pc->namelist_orig ?
> > pc->namelist_orig : pc->namelist,
> > is_livepatch() ? " [LIVEPATCH]" :
"",
> > + is_livepatch_transition() ? "
> > + [TRANSITION]" : "",
> > is_kernel_tainted() ? " [TAINTED]" :
"");
> > }
> >
> > --
> > 2.47.3
> >