[pve-devel] [PATCH kernel 1/6] build: keep unstripped kernel and module files

["Fabian Grünbichler" <f.gruenbichler@proxmox.com>]

and put them into a new -dbgsym package for usage with
crash/kdump-tools/...

fixes #3465, and now allows to do the following (after installing
and configuring kdump-tools to collect kernel crash dumps) when the
system crashes:

  $ apt install pve-kernel-5.11.21-1-dbgsym
  $ crash /usr/lib/debug/boot/vmlinux-5.11.21-1-pve /var/crash/202106151236/dump.202106151236

  crash 7.2.9
  Copyright (C) 2002-2020  Red Hat, Inc.
  Copyright (C) 2004, 2005, 2006, 2010  IBM Corporation
  Copyright (C) 1999-2006  Hewlett-Packard Co
  Copyright (C) 2005, 2006, 2011, 2012  Fujitsu Limited
  Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
  Copyright (C) 2005, 2011  NEC Corporation
  Copyright (C) 1999, 2002, 2007  Silicon Graphics, Inc.
  Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
  This program is free software, covered by the GNU General Public License,
  and you are welcome to change it and/or distribute copies of it under
  certain conditions.  Enter "help copying" to see the conditions.
  This program has absolutely no warranty.  Enter "help warranty" for details.

  GNU gdb (GDB) 7.6
  Copyright (C) 2013 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
  and "show warranty" for details.
  This GDB was configured as "x86_64-unknown-linux-gnu"...

  WARNING: kernel relocated [812MB]: patching 136336 gdb minimal_symbol values

        KERNEL: /usr/lib/debug/boot/vmlinux-5.11.21-1-pve
      DUMPFILE: /var/crash/202106151236/dump.202106151236  [PARTIAL DUMP]
          CPUS: 4
          DATE: Tue Jun 15 12:36:38 CEST 2021
        UPTIME: 00:06:21
  LOAD AVERAGE: 0.04, 0.11, 0.08
         TASKS: 272
      NODENAME: test
       RELEASE: 5.11.21-1-pve
       VERSION: #1 SMP PVE 5.11.21-1 (Tue, 01 Jun 2021 16:38:57 +0200)
       MACHINE: x86_64  (3696 Mhz)
        MEMORY: 8 GB
         PANIC: "Kernel panic - not syncing: sysrq triggered crash"
           PID: 3167
       COMMAND: "bash"
          TASK: ffff9220c8f5be00  [THREAD_INFO: ffff9220c8f5be00]
           CPU: 3
         STATE: TASK_RUNNING (PANIC)

  crash> bt
  PID: 3167   TASK: ffff9220c8f5be00  CPU: 3   COMMAND: "bash"
   #0 [ffffa24ec0bfbc80] machine_kexec at ffffffffb3c751f3
   #1 [ffffa24ec0bfbce0] __crash_kexec at ffffffffb3d61092
   #2 [ffffa24ec0bfbdb0] panic at ffffffffb47b769d
   #3 [ffffa24ec0bfbe30] sysrq_handle_crash at ffffffffb434da4a
   #4 [ffffa24ec0bfbe40] __handle_sysrq.cold at ffffffffb47e2cdc
   #5 [ffffa24ec0bfbe78] write_sysrq_trigger at ffffffffb434e3f8
   #6 [ffffa24ec0bfbe90] proc_reg_write at ffffffffb3fc09ea
   #7 [ffffa24ec0bfbeb0] vfs_write at ffffffffb3f143b6
   #8 [ffffa24ec0bfbee8] ksys_write at ffffffffb3f16b97
   #9 [ffffa24ec0bfbf28] __x64_sys_write at ffffffffb3f16c2a
  #10 [ffffa24ec0bfbf38] do_syscall_64 at ffffffffb480e868
  #11 [ffffa24ec0bfbf50] entry_SYSCALL_64_after_hwframe at ffffffffb4a0008c
      RIP: 00007f367f7baf33  RSP: 00007ffe6175dc98  RFLAGS: 00000246
      RAX: ffffffffffffffda  RBX: 0000000000000002  RCX: 00007f367f7baf33
      RDX: 0000000000000002  RSI: 0000560510e640b0  RDI: 0000000000000001
      RBP: 0000560510e640b0   R8: 000000000000000a   R9: 0000000000000001
      R10: 0000560510e5f800  R11: 0000000000000246  R12: 0000000000000002
      R13: 00007f367f88b6a0  R14: 0000000000000002  R15: 00007f367f88b8a0
      ORIG_RAX: 0000000000000001  CS: 0033  SS: 002b

as well as lots of other fun things (see 'help' after opening a crash dump).

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---

Notes:
    requires a recent enough version of kdump-tools/makedumpfile, so bullseye+
    unless we provide our own backport for buster..
    
    the resulting package is obviously quite large, so we don't want to install it
    automatically

 debian/control.in |  8 ++++++++
 debian/rules      | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/debian/control.in b/debian/control.in
index 1f235f0..a9c8dd8 100644
--- a/debian/control.in
+++ b/debian/control.in
@@ -71,6 +71,14 @@ Recommends: grub-pc | grub-efi-amd64 | grub-efi-ia32 | grub-efi-arm64,
 Description: The Proxmox PVE Kernel Image
  This package contains the linux kernel and initial ramdisk used for booting
 
+Package: pve-kernel-@KVNAME@-dbgsym
+Architecture: any
+Provides: linux-debug
+Section: devel
+Priority: optional
+Description: The Proxmox PVE Kernel debug image
+ This package provides the kernel debug image for version @KVNAME@. The debug kernel image contained in this package is NOT meant to boot from - it is uncompressed, and unstripped, and suitable for use with crash/kdump-tools/.. to analyze kernel crashes. This package also contains the pve-kernel modules in their unstripped version.
+
 Package: pve-kernel-libc-dev
 Section: devel
 Priority: optional
diff --git a/debian/rules b/debian/rules
index 7b1b251..ec22136 100755
--- a/debian/rules
+++ b/debian/rules
@@ -14,6 +14,7 @@ include debian/rules.d/${DEB_BUILD_ARCH}.mk
 CHANGELOG_DATE:=$(shell dpkg-parsechangelog -SDate)
 
 PVE_KERNEL_PKG=pve-kernel-${KVNAME}
+PVE_DEBUG_KERNEL_PKG=pve-kernel-${KVNAME}-dbgsym
 PVE_HEADER_PKG=pve-headers-${KVNAME}
 PVE_USR_HEADER_PKG=pve-kernel-libc-dev
 LINUX_TOOLS_PKG=linux-tools-${KERNEL_MAJMIN}
@@ -132,6 +133,16 @@ binary: install
 	install -m 644 $(addprefix ${MODULES}/,zfs.ko zavl.ko znvpair.ko zunicode.ko zcommon.ko icp.ko zlua.ko spl.ko zzstd.ko) debian/${PVE_KERNEL_PKG}/lib/modules/${KVNAME}/zfs
 	# remove firmware
 	rm -rf debian/${PVE_KERNEL_PKG}/lib/firmware
+
+	# debug package
+	mkdir -p debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/lib/modules/${KVNAME}
+	mkdir debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/boot
+	install -m 644 ${KERNEL_SRC}/vmlinux debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/boot/vmlinux-${KVNAME}
+	cp -r debian/${PVE_KERNEL_PKG}/lib/modules/${KVNAME} debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/lib/modules/
+	rm -f debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/lib/modules/${KVNAME}/source
+	rm -f debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/lib/modules/${KVNAME}/build
+	rm -f debian/${PVE_DEBUG_KERNEL_PKG}/usr/lib/debug/lib/modules/${KVNAME}/modules.*
+
 	# strip debug info
 	find debian/${PVE_KERNEL_PKG}/lib/modules -name \*.ko -print | while read f ; do strip --strip-debug "$$f"; done
 	# finalize
-- 
2.30.2