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  1. Jul 08, 2021
    • Stephen Boyd's avatar
      kdump: use vmlinux_build_id to simplify · 44e8a5e9
      Stephen Boyd authored
      We can use the vmlinux_build_id array here now instead of open coding it.
      This mostly consolidates code.
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-14-swboyd@chromium.org
      
      
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      44e8a5e9
    • Stephen Boyd's avatar
      buildid: fix kernel-doc notation · 3f14d029
      Stephen Boyd authored
      Kernel doc should use "Return:" instead of "Returns" to properly reflect
      the return values.
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-13-swboyd@chromium.org
      
      
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3f14d029
    • Stephen Boyd's avatar
      buildid: mark some arguments const · 60eec326
      Stephen Boyd authored
      These arguments are never modified so they can be marked const to indicate
      as such.
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-12-swboyd@chromium.org
      
      
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      60eec326
    • Stephen Boyd's avatar
      dump_stack: add vmlinux build ID to stack traces · 22f4e66d
      Stephen Boyd authored
      Add the running kernel's build ID[1] to the stacktrace information header.
      This makes it simpler for developers to locate the vmlinux with full
      debuginfo for a particular kernel stacktrace.  Combined with
      scripts/decode_stracktrace.sh, a developer can download the correct
      vmlinux from a debuginfod[2] server and find the exact file and line
      number for the functions plus offsets in a stacktrace.
      
      This is especially useful for pstore crash debugging where the kernel
      crashes are recorded in the pstore logs and the recovery kernel is
      different or the debuginfo doesn't exist on the device due to space
      concerns (the data can be large and a security concern).  The stacktrace
      can be analyzed after the crash by using the build ID to find the matching
      vmlinux and understand where in the function something went wrong.
      
      Example stacktrace from lkdtm:
      
       WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
       Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
       CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
       Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
       pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
       pc : lkdtm_WARNING+0x28/0x30 [lkdtm]
      
      The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID,
      following the kernel version number. Put it all behind a config option,
      STACKTRACE_BUILD_ID, so that kernel developers can remove this
      information if they decide it is too much.
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-5-swboyd@chromium.org
      Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
      Link: https://sourceware.org/elfutils/Debuginfod.html
      
       [2]
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      22f4e66d
    • Stephen Boyd's avatar
      buildid: stash away kernels build ID on init · 83cc6fa0
      Stephen Boyd authored
      Parse the kernel's build ID at initialization so that other code can print
      a hex format string representation of the running kernel's build ID.  This
      will be used in the kdump and dump_stack code so that developers can
      easily locate the vmlinux debug symbols for a crash/stacktrace.
      
      [swboyd@chromium.org: fix implicit declaration of init_vmlinux_build_id()]
        Link: https://lkml.kernel.org/r/CAE-0n51UjTbay8N9FXAyE7_aR2+ePrQnKSRJ0gbmRsXtcLBVaw@mail.gmail.com
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-4-swboyd@chromium.org
      
      
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Acked-by: default avatarBaoquan He <bhe@redhat.com>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      83cc6fa0
    • Stephen Boyd's avatar
      buildid: add API to parse build ID out of buffer · 7eaf3cf3
      Stephen Boyd authored
      Add an API that can parse the build ID out of a buffer, instead of a vma,
      to support printing a kernel module's build ID for stack traces.
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-3-swboyd@chromium.org
      
      
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7eaf3cf3
    • Stephen Boyd's avatar
      buildid: only consider GNU notes for build ID parsing · a010d79b
      Stephen Boyd authored
      Patch series "Add build ID to stacktraces", v6.
      
      This series adds the kernel's build ID[1] to the stacktrace header printed
      in oops messages, warnings, etc.  and the build ID for any module that
      appears in the stacktrace after the module name.  The goal is to make the
      stacktrace more self-contained and descriptive by including the relevant
      build IDs in the kernel logs when something goes wrong.  This can be used
      by post processing tools like script/decode_stacktrace.sh and kernel
      developers to easily locate the debug info associated with a kernel crash
      and line up what line and file things started falling apart at.
      
      To show how this can be used I've included a patch to decode_stacktrace.sh
      that downloads the debuginfo from a debuginfod server.  This also includes
      some patches to make the buildid.c file use more const arguments and
      consolidate logic into buildid.c from kdump.  These are left to the end as
      they were mostly cleanup patches.
      
      Here's an example lkdtm stacktrace on arm64.
      
       WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
       Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
       CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
       Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
       pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
       pc : lkdtm_WARNING+0x28/0x30 [lkdtm]
       lr : lkdtm_do_action+0x24/0x40 [lkdtm]
       sp : ffffffc0134fbca0
       x29: ffffffc0134fbca0 x28: ffffff92d53ba240
       x27: 0000000000000000 x26: 0000000000000000
       x25: 0000000000000000 x24: ffffffe3622352c0
       x23: 0000000000000020 x22: ffffffe362233366
       x21: ffffffe3622352e0 x20: ffffffc0134fbde0
       x19: 0000000000000008 x18: 0000000000000000
       x17: ffffff929b6536fc x16: 0000000000000000
       x15: 0000000000000000 x14: 0000000000000012
       x13: ffffffe380ed892c x12: ffffffe381d05068
       x11: 0000000000000000 x10: 0000000000000000
       x9 : 0000000000000001 x8 : ffffffe362237000
       x7 : aaaaaaaaaaaaaaaa x6 : 0000000000000000
       x5 : 0000000000000000 x4 : 0000000000000001
       x3 : 0000000000000008 x2 : ffffff93fef25a70
       x1 : ffffff93fef15788 x0 : ffffffe3622352e0
       Call trace:
        lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
        direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
        full_proxy_write+0x74/0xa4
        vfs_write+0xec/0x2e8
        ksys_write+0x84/0xf0
        __arm64_sys_write+0x24/0x30
        el0_svc_common+0xf4/0x1c0
        do_el0_svc_compat+0x28/0x3c
        el0_svc_compat+0x10/0x1c
        el0_sync_compat_handler+0xa8/0xcc
        el0_sync_compat+0x178/0x180
       ---[ end trace 3d95032303e59e68 ]---
      
      This patch (of 13):
      
      Some kernel elf files have various notes that also happen to have an elf
      note type of '3', which matches NT_GNU_BUILD_ID but the note name isn't
      "GNU".  For example, this note trips up the existing logic:
      
       Owner  Data size   Description
       Xen    0x00000008  Unknown note type: (0x00000003) description data: 00 00 00 ffffff80 ffffffff ffffffff ffffffff ffffffff
      
      Let's make sure that it is a GNU note when parsing the build ID so that we
      can use this function to parse a vmlinux's build ID too.
      
      Link: https://lkml.kernel.org/r/20210511003845.2429846-1-swboyd@chromium.org
      Link: https://lkml.kernel.org/r/20210511003845.2429846-2-swboyd@chromium.org
      
      
      Fixes: bd7525da ("bpf: Move stack_map_get_build_id into lib")
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Reported-by: default avatarPetr Mladek <pmladek@suse.com>
      Tested-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Evan Green <evgreen@chromium.org>
      Cc: Hsin-Yi Wang <hsinyi@chromium.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Will Deacon <will@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a010d79b
  2. Jan 15, 2021
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