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authorVijay Balakrishna <vijayb@linux.microsoft.com>2020-08-12 03:36:33 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-12 19:58:01 +0200
commit0935288c6e008c0682ab6171fb5605dcc049e7bd (patch)
tree019e7a84e892724c2659ad0747b81b065cf0a738 /include
parentexec: move path_noexec() check earlier (diff)
downloadlinux-0935288c6e008c0682ab6171fb5605dcc049e7bd.tar.xz
linux-0935288c6e008c0682ab6171fb5605dcc049e7bd.zip
kdump: append kernel build-id string to VMCOREINFO
Make kernel GNU build-id available in VMCOREINFO. Having build-id in VMCOREINFO facilitates presenting appropriate kernel namelist image with debug information file to kernel crash dump analysis tools. Currently VMCOREINFO lacks uniquely identifiable key for crash analysis automation. Regarding if this patch is necessary or matching of linux_banner and OSRELEASE in VMCOREINFO employed by crash(8) meets the need -- IMO, build-id approach more foolproof, in most instances it is a cryptographic hash generated using internal code/ELF bits unlike kernel version string upon which linux_banner is based that is external to the code. I feel each is intended for a different purpose. Also OSRELEASE is not suitable when two different kernel builds from same version with different features enabled. Currently for most linux (and non-linux) systems build-id can be extracted using standard methods for file types such as user mode crash dumps, shared libraries, loadable kernel modules etc., This is an exception for linux kernel dump. Having build-id in VMCOREINFO brings some uniformity for automation tools. Tyler said: : I think this is a nice improvement over today's linux_banner approach for : correlating vmlinux to a kernel dump. : : The elf notes parsing in this patch lines up with what is described in in : the "Notes (Nhdr)" section of the elf(5) man page. : : BUILD_ID_MAX is sufficient to hold a sha1 build-id, which is the default : build-id type today in GNU ld(2). It is also sufficient to hold the : "fast" build-id, which is the default build-id type today in LLVM lld(2). Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Link: http://lkml.kernel.org/r/1591849672-34104-1-git-send-email-vijayb@linux.microsoft.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/crash_core.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 525510a9f965..6594dbc34a37 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -38,6 +38,8 @@ phys_addr_t paddr_vmcoreinfo_note(void);
#define VMCOREINFO_OSRELEASE(value) \
vmcoreinfo_append_str("OSRELEASE=%s\n", value)
+#define VMCOREINFO_BUILD_ID(value) \
+ vmcoreinfo_append_str("BUILD-ID=%s\n", value)
#define VMCOREINFO_PAGESIZE(value) \
vmcoreinfo_append_str("PAGESIZE=%ld\n", value)
#define VMCOREINFO_SYMBOL(name) \
@@ -64,6 +66,10 @@ extern unsigned char *vmcoreinfo_data;
extern size_t vmcoreinfo_size;
extern u32 *vmcoreinfo_note;
+/* raw contents of kernel .notes section */
+extern const void __start_notes __weak;
+extern const void __stop_notes __weak;
+
Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len);
void final_note(Elf_Word *buf);