New: makedumpfile can not open /proc/vmcore

https://bugzilla.kernel.org/show_bug.cgi?id=217702

Bug ID: 217702
Summary: makedumpfile can not open /proc/vmcore
Product: Platform Specific/Hardware
Version: 2.5
Hardware: All
OS: Linux
Status: NEW
Severity: normal
Priority: P3
Component: PPC-64
Assignee: [email protected]
Reporter: [email protected]
Regression: No

This bug should be introduced by the
commit 606787fed7268feb256957872586370b56af697a

Author: Nicholas Piggin <[email protected]>
Date:   Tue Jun 6 19:38:32 2023 +1000

powerpc/64s: Remove support for ELFv1 little endian userspace

ELFv2 was introduced together with little-endian. ELFv1 with LE has never been a thing. The GNU toolchain can create such a beast, but anyone doing that is a maniac who needs to be stopped so I consider this patch a feature.

And can be workaround by the following draft patch:

b/arch/powerpc/kexec/file_load_64.c
index 110d28bede2a..6af49c90c4b2 100644

@@ -782,6 +782,18 @@ static void update_backup_region_phdr(struct kimage

*image, Elf64_Ehdr *ehdr)

        }

}

+/**
+ * 64le only supports ELFv2 64-bit binaries (64be supports v1 and v2).
+ */
+static inline void update_elfcorehdr_eflags(Elf64_Ehdr *ehdr) +{
+#if defined(CONFIG_PPC64) && defined(CONFIG_CPU_LITTLE_ENDIAN)
+ ehdr->e_flags = 0x2;
+#endif
+}
+
+
+
/**
* load_elfcorehdr_segment - Setup crash memory ranges and initialize
elfcorehdr
* segment needed to load kdump kernel.
@@ -810,6 +822,7 @@ static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)

        /* Fix the offset for backup region in the ELF header */
        update_backup_region_phdr(image, headers);

+ update_elfcorehdr_eflags(headers);

        kbuf->buffer = headers;
        kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;

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https://bugzilla.kernel.org/show_bug.cgi?id=217702

Michael Ellerman ([email protected]) changed:

What |Removed |Added
----------------------------------------------------------------------------

             Status|NEW                         |RESOLVED
                 CC|                            |[email protected]
         Resolution|---                         |CODE_FIX

--- Comment #1 from Michael Ellerman ([email protected]) --- This should be fixed in mainline due to the revert:

106ea7ffd56b ("Revert "powerpc/64s: Remove support for ELFv1 little endian userspace"")

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