Re: [PATCH v9 9/9] liveupdate: kho: Use %pe format specifier for error pointer printing

[Zhu Yanjun]

在 2025/11/1 7:23, Pasha Tatashin 写道:

From: Zhu Yanjun <yanjun....@linux.dev>

Make pr_xxx() call to use the %pe format specifier instead of %d.
The %pe specifier prints a symbolic error string (e.g., -ENOMEM,
-EINVAL) when given an error pointer created with ERR_PTR(err).

This change enhances the clarity and diagnostic value of the error
message by showing a descriptive error name rather than a numeric
error code.

Note, that some err are still printed by value, as those errors
might come from libfdt and not regular errnos.

Signed-off-by: Zhu Yanjun <yanjun....@linux.dev>
Co-developed-by: Pasha Tatashin <pasha.tatas...@soleen.com>
Signed-off-by: Pasha Tatashin <pasha.tatas...@soleen.com>

Appreciate your help, Pasha

Yanjun.Zhu

Reviewed-by: Simon Horman <ho...@kernel.org>
---
  kernel/liveupdate/kexec_handover.c         |  4 ++--
  kernel/liveupdate/kexec_handover_debugfs.c | 10 ++++++----
  2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/liveupdate/kexec_handover.c 
b/kernel/liveupdate/kexec_handover.c
index be945c133a2f..167c761988d3 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -1448,8 +1448,8 @@ void __init kho_populate(phys_addr_t fdt_phys, u64 
fdt_len,
                memblock_add(area->addr, size);
                err = memblock_mark_kho_scratch(area->addr, size);
                if (WARN_ON(err)) {
-                       pr_warn("failed to mark the scratch region 0x%pa+0x%pa: 
%d",
-                               &area->addr, &size, err);
+                       pr_warn("failed to mark the scratch region 0x%pa+0x%pa: 
%pe",
+                               &area->addr, &size, ERR_PTR(err));
                        goto out;
                }
                pr_debug("Marked 0x%pa+0x%pa as scratch", &area->addr, &size);
diff --git a/kernel/liveupdate/kexec_handover_debugfs.c 
b/kernel/liveupdate/kexec_handover_debugfs.c
index 46e9e6c0791f..ac739d25094d 100644
--- a/kernel/liveupdate/kexec_handover_debugfs.c
+++ b/kernel/liveupdate/kexec_handover_debugfs.c
@@ -150,8 +150,8 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, 
const void *fdt)
                err = __kho_debugfs_fdt_add(&dbg->fdt_list, sub_fdt_dir, name,
                                            phys_to_virt(*fdt_phys));
                if (err) {
-                       pr_warn("failed to add fdt %s to debugfs: %d\n", name,
-                               err);
+                       pr_warn("failed to add fdt %s to debugfs: %pe\n", name,
+                               ERR_PTR(err));
                        continue;
                }
        }
@@ -168,8 +168,10 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, 
const void *fdt)
         * reviving state from KHO and setting up KHO for the next
         * kexec.
         */
-       if (err)
-               pr_err("failed exposing handover FDT in debugfs: %d\n", err);
+       if (err) {
+               pr_err("failed exposing handover FDT in debugfs: %pe\n",
+                      ERR_PTR(err));
+       }
  }

__init int kho_out_debugfs_init(struct kho_debugfs *dbg)

--
Best Regards,
Yanjun.Zhu