[Crash-utility] Re: [PATCH RESEND] Add a command line option to retrieve build-id

Date: Mon, 8 Dec 2025 10:16:17 -0800 From: Munehisa Kamata <kamatam(a)amazon.com&gt; Subject: [Crash-utility] [PATCH RESEND] Add a command line option to retrieve build-id To: <devel(a)lists.crash-utility.osci.io&gt; Cc: Munehisa Kamata <kamatam(a)amazon.com&gt; Message-ID: <20251208181617.420350-1-kamatam(a)amazon.com&gt; Content-Type: text/plain Resending because my previous post is held for presumably being sent without a list subscription. Since Linux kernel commit 0935288c6e00 ("kdump: append kernel build-id string to VMCOREINFO") merged in v5.9, VMCOREINFO data contains a kernel build-id. Add a simple --build-id command line option that retrieves the build-id from a kernel dump file, which works just like the existing --osrelease option (and the implementation mimics it). Example: # crash --build-id /var/crash/127.0.0.1-2025-11-28-00\:33\:07/vmcore 03cc3b4eb67df4e66a6a794a39521bafabef0886

verification between namelist and dump file, this would be still handy for some scripting or automation tasks without namelist. Signed-off-by: Munehisa Kamata <kamatam(a)amazon.com&gt; --- crash.8 | 7 +++++++ defs.h | 1 + diskdump.c | 17 +++++++++++++++++ help.c | 6 ++++++ main.c | 30 ++++++++++++++++++++++++++++++ makedumpfile.c | 40 ++++++++++++++++++++++++++++++++++------ netdump.c | 17 +++++++++++++++++ 7 files changed, 112 insertions(+), 6 deletions(-) diff --git a/crash.8 b/crash.8 index c7dc27d..4c06cb7 100644 --- a/crash.8 +++ b/crash.8 @@ -398,6 +398,13 @@ Display the OSRELEASE vmcoreinfo string from a kdump .I dumpfile header. .TP +.BI --build-id \ dumpfile +Display the BUILD-ID vmcoreinfo string from a kdump +.I dumpfile +header. +Note: this option only works for kernel (>=v5.9); otherwise it +prints "unknown" and exits with non-zero status. +.TP .BI --hyper Force the session to be that of a Xen hypervisor. .TP diff --git a/defs.h b/defs.h index 24dad93..ff8041c 100644 --- a/defs.h +++ b/defs.h @@ -570,6 +570,7 @@ struct program_context { #define MEMSRC_LOCAL (0x80000ULL) #define REDZONE (0x100000ULL) #define VMWARE_VMSS_GUESTDUMP (0x200000ULL) +#define GET_BUILD_ID (0x400000ULL) char *cleanup; char *namelist_orig; char *namelist_debug_orig; diff --git a/diskdump.c b/diskdump.c index b1ca0a7..0ff8782 100644 --- a/diskdump.c +++ b/diskdump.c @@ -91,6 +91,7 @@ static void dump_vmcoreinfo(FILE *); static void dump_note_offsets(FILE *); static char *vmcoreinfo_read_string(const char *); static void diskdump_get_osrelease(void); +static void diskdump_get_build_id(void); static int valid_note_address(unsigned char *); /* For split dumpfile */ @@ -1074,6 +1075,9 @@ is_diskdump(char *file) if (pc->flags2 & GET_OSRELEASE) diskdump_get_osrelease(); + if (pc->flags2 & GET_BUILD_ID) + diskdump_get_build_id(); + #ifdef LZO if (lzo_init() == LZO_E_OK) dd->flags |= LZO_SUPPORTED; @@ -2446,6 +2450,19 @@ diskdump_get_osrelease(void) pc->flags2 &= ~GET_OSRELEASE; } +static void +diskdump_get_build_id(void) +{ + char *string; + + if ((string = vmcoreinfo_read_string("BUILD-ID"))) { + fprintf(fp, "%s\n", string); + free(string); + } + else + pc->flags2 &= ~GET_BUILD_ID; +} + static int valid_note_address(unsigned char *offset) { diff --git a/help.c b/help.c index 78d7a5c..1a21062 100644 --- a/help.c +++ b/help.c @@ -266,6 +266,12 @@ char *program_usage_info[] = { " Display the OSRELEASE vmcoreinfo string from a kdump dumpfile", " header.", "", + " --build-id dumpfile", + " Display the BUILD-ID vmcoreinfo string from a kdump dumpfile", + " header.", + " Note: this option only works for kernel(>=v5.9); otherwise it", + " prints \"unknown\" and exits with non-zero status", + "", " --hyper", " Force the session to be that of a Xen hypervisor.", "", diff --git a/main.c b/main.c index 71bcc15..d4c335b 100644 --- a/main.c +++ b/main.c @@ -29,6 +29,7 @@ static void check_xen_hyper(void); static void show_untrusted_files(void); static void get_osrelease(char *); static void get_log(char *); +static void get_build_id(char *); static struct option long_options[] = { {"memory_module", required_argument, 0, 0}, @@ -66,6 +67,7 @@ static struct option long_options[] = { {"no_elf_notes", 0, 0, 0}, {"osrelease", required_argument, 0, 0}, {"log", required_argument, 0, 0}, + {"build-id", required_argument, 0, 0}, {"hex", 0, 0, 0}, {"dec", 0, 0, 0}, {"no_strip", 0, 0, 0}, @@ -276,6 +278,11 @@ main(int argc, char **argv) get_log(optarg); } + else if (STREQ(long_options[option_index].name, "build-id")) { + pc->flags2 |= GET_BUILD_ID; + get_build_id(optarg); + } + else if (STREQ(long_options[option_index].name, "hex")) { pc->flags2 |= RADIX_OVERRIDE; pc->output_radix = 16; @@ -1502,6 +1509,8 @@ dump_program_context(void) fprintf(fp, "%sREDZONE", others++ ? "|" : ""); if (pc->flags2 & VMWARE_VMSS_GUESTDUMP) fprintf(fp, "%sVMWARE_VMSS_GUESTDUMP", others++ ? "|" : ""); + if (pc->flags2 & GET_BUILD_ID) + fprintf(fp, "%sGET_BUILD_ID", others++ ? "|" : ""); fprintf(fp, ")\n"); fprintf(fp, " namelist: %s\n", pc->namelist); @@ -1972,6 +1981,27 @@ get_log(char *dumpfile) clean_exit(retval); } +static void +get_build_id(char *dumpfile) +{ + int retval = 1; + + if (is_flattened_format(dumpfile)) { + if (pc->flags2 & GET_BUILD_ID) + retval = 0; + } else if (is_diskdump(dumpfile)) { + if (pc->flags2 & GET_BUILD_ID) + retval = 0; + } else if (is_kdump(dumpfile, KDUMP_LOCAL)) { + if (pc->flags2 & GET_BUILD_ID) + retval = 0; + } + + if (retval) + fprintf(fp, "unknown\n"); + + clean_exit(retval); +} char * no_vmcoreinfo(const char *unused) diff --git a/makedumpfile.c b/makedumpfile.c index 26d12b6..ee03199 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -24,6 +24,7 @@ #include <byteswap.h> static void flattened_format_get_osrelease(char *); +static void flattened_format_get_build_id(char *); int flattened_format = 0; @@ -196,7 +197,7 @@ read_all_makedumpfile_data_header(char *file) void check_flattened_format(char *file) { - int fd, get_osrelease; + int fd, get_osrelease, get_build_id; struct stat stat; struct makedumpfile_header fh; @@ -206,6 +207,12 @@ check_flattened_format(char *file) } else get_osrelease = FALSE; + if (pc->flags2 & GET_BUILD_ID) { + get_build_id = TRUE; + pc->flags2 &= ~GET_BUILD_ID; + } else + get_build_id = FALSE; + if (flattened_format) goto out; @@ -237,6 +244,11 @@ check_flattened_format(char *file) return; } + if (get_build_id) { + flattened_format_get_build_id(file); + return; + } + if (!read_all_makedumpfile_data_header(file)) return; @@ -251,6 +263,9 @@ check_flattened_format(char *file) out: if (get_osrelease) pc->flags2 |= GET_OSRELEASE; + + if (get_build_id) + pc->flags2 |= GET_BUILD_ID; } static int @@ -368,26 +383,39 @@ dump_flat_header(FILE *ofp) } static void -flattened_format_get_osrelease(char *file) +flattened_format_get_common(char *file, char *key, ulonglong flag) { int c; FILE *pipe; - char buf[BUFSIZE], *p1, *p2; + char keybuf[BUFSIZE], buf[BUFSIZE], *p1, *p2; - c = strlen("OSRELEASE="); + sprintf(keybuf, "%s=", key); + c = strlen(keybuf); sprintf(buf, "/usr/bin/strings -n %d %s", c, file); if ((pipe = popen(buf, "r")) == NULL) return; for (c = 0; (c < 100) && fgets(buf, BUFSIZE-1, pipe); c++) { - if ((p1 = strstr(buf, "OSRELEASE="))) { + if ((p1 = strstr(buf, keybuf))) { p2 = strstr(p1, "="); fprintf(fp, "%s", p2+1); flattened_format = TRUE; - pc->flags2 |= GET_OSRELEASE; + pc->flags2 |= flag; } } pclose(pipe); } + +static void +flattened_format_get_osrelease(char *file) +{ + flattened_format_get_common(file, "OSRELEASE", GET_OSRELEASE); +} + +static void +flattened_format_get_build_id(char *file) +{ + flattened_format_get_common(file, "BUILD-ID", GET_BUILD_ID); +} diff --git a/netdump.c b/netdump.c index c7ff009..ba1c6c4 100644 --- a/netdump.c +++ b/netdump.c @@ -50,6 +50,7 @@ static int proc_kcore_init_64(FILE *, int); static char *get_regs_from_note(char *, ulong *, ulong *); static void kdump_get_osrelease(void); static char *vmcoreinfo_read_string(const char *); +static void kdump_get_build_id(void); #define ELFSTORE 1 @@ -477,6 +478,10 @@ is_netdump(char *file, ulong source_query) get_log_from_vmcoreinfo(file); } + if ((source_query == KDUMP_LOCAL) && + (pc->flags2 & GET_BUILD_ID)) + kdump_get_build_id(); + return nd->header_size; bailout: @@ -4996,6 +5001,18 @@ kdump_get_osrelease(void) pc->flags2 &= ~GET_OSRELEASE; } +static void +kdump_get_build_id(void) +{ + char *string; + + if ((string = vmcoreinfo_read_string("BUILD-ID"))) { + fprintf(fp, "%s\n", string); + free(string); + } else + pc->flags2 &= ~GET_BUILD_ID; +} + void dump_registers_for_qemu_mem_dump(void) { -- 2.47.3