[PATCH v3] kdump-lib: switch to the kexec_file_load() syscall on x86_64 by default

[Lianbo Jiang]

UEFI Secure boot is a signature verification mechanism, is designed to
prevent malicious code being loaded and executed at the early boot stage.
This makes sure that code executed is trusted by firmware.

Previously, with kexec_file_load() interface, kernel prevents unsigned
kernel image from being loaded if secure boot is enabled. So kdump will
detect whether secure boot is enabled firstly, then decide which interface
is chosen to execute, kexec_load() or kexec_file_load(). Otherwise unsigned
kernel loading will fail if secure boot enabled, and kexec_file_load() is
entered.

Now, the implementation of kexec_file_load() is adjusted in below commit.
With this change, if CONFIG_KEXEC_SIG_FORCE is not set, unsigned kernel
still has chance to be allowed to load under some conditions.

commit 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG
and KEXEC_SIG_FORCE")

And in the current fedora and RHEL, CONFIG_KEXEC_SIG_FORCE is not set, only
CONFIG_KEXEC_SIG and CONFIG_BZIMAGE_VERIFY_SIG are set on x86_64 by default.
It's time to spread kexec_file_load() onto all systems of x86_64, including
Secute-boot platforms and legacy platforms. Please refer to the following
form.

.----------------------------------------------------------------------.
| .                    |     signed kernel     |    unsigned kernel    |
|    .      types      |-----------------------|-----------------------|
|       .              |Secure boot|  Legacy   |Secure boot|  Legacy   |
|          .           |-----------|-----------|-----------|-----------|
| options     .        | prev| now | prev| now |     |     | prev| now |
|                .     |(file|(file|(only|(file| prev| now |(only|(file|
|                    . |load)|load)|load)|load)|     |     |load)|load)|
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
|SIG_FORCE is not set  |succ |succ |succ |succ |  X  |  X  |succ |succ |
|BZIMAGE_VERIFY_SIG=y  |     |     |     |     |     |     |     |     |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
|SIG_FORCE is not set  |     |     |     |     |     |     |     |     |
|BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail |  X  |  X  |succ |fail |
|not set               |     |     |     |     |     |     |     |     |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
|SIG_FORCE=y           |succ |succ |succ |fail |  X  |  X  |succ |fail |
|BZIMAGE_VERIFY_SIG=y  |     |     |     |     |     |     |     |     |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
|SIG_FORCE=y           |     |     |     |     |     |     |     |     |
|BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail |  X  |  X  |succ |fail |
|not set               |     |     |     |     |     |     |     |     |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG is not set  |     |     |     |     |     |     |     |     |
|SIG_FORCE is not set  |     |     |     |     |     |     |     |     |
|BZIMAGE_VERIFY_SIG is |fail |fail |succ |succ |  X  |  X  |succ |succ |
|not set               |     |     |     |     |     |     |     |     |
 ----------------------------------------------------------------------
Note:
[1] The 'X' indicates that the 1st kernel(unsigned) can not boot when the
    Secure boot is enabled.

Hence, in this patch, if on x86, lets use the kexec_file_load() only. See if
anything wrong happened in this case, in Fedora firstly for the time being.

Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt;
---
 dracut-early-kdump.sh |  4 ++--
 kdump-lib.sh          | 31 +++++++++++--------------------
 kdumpctl              | 10 ++++------
 3 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh
index 69a34eb996cd..bfb923d6efa1 100755
--- a/dracut-early-kdump.sh
+++ b/dracut-early-kdump.sh
@@ -43,8 +43,8 @@ early_kdump_load()
 
     EARLY_KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
 
-    if is_secure_boot_enforced; then
-        echo "Secure Boot is enabled. Using kexec file based syscall."
+    if use_kexec_file_load; then
+        echo "Using kexec file based syscall."
         EARLY_KEXEC_ARGS="$EARLY_KEXEC_ARGS -s"
     fi
 
diff --git a/kdump-lib.sh b/kdump-lib.sh
index f393c76b9cbb..5b6684992553 100755
--- a/kdump-lib.sh
+++ b/kdump-lib.sh
@@ -589,30 +589,21 @@ need_64bit_headers()
     print (strtonum("0x" r[2]) > strtonum("0xffffffff")); }'`
 }
 
-# Check if secure boot is being enforced.
 #
-# Per Peter Jones, we need check efivar SecureBoot-$(the UUID) and
-# SetupMode-$(the UUID), they are both 5 bytes binary data. The first four
-# bytes are the attributes associated with the variable and can safely be
-# ignored, the last bytes are one-byte true-or-false variables. If SecureBoot
-# is 1 and SetupMode is 0, then secure boot is being enforced.
+# Currently, Secure Boot is only used on x86_64 and kernel enabled the
+# kexec_file_load() on x86_64 by default.
+# In addition, kernel also enables the option KEXEC_SIG, which makes the
+# kexec_file_load() syscall checks for a valid signature of the kernel
+# image if there is a signature(It must be valid). And the images can
+# still be loaded without a valid signature. So let kexec-tools change
+# as well.
 #
-# Assume efivars is mounted at /sys/firmware/efi/efivars.
-is_secure_boot_enforced()
+use_kexec_file_load()
 {
-    local secure_boot_file setup_mode_file
-    local secure_boot_byte setup_mode_byte
+    local arch_name=`uname -m`
 
-    secure_boot_file=$(find /sys/firmware/efi/efivars -name SecureBoot-* 2>/dev/null)
-    setup_mode_file=$(find /sys/firmware/efi/efivars -name SetupMode-* 2>/dev/null)
-
-    if [ -f "$secure_boot_file" ] && [ -f "$setup_mode_file"
]; then
-        secure_boot_byte=$(hexdump -v -e '/1 "%d\ "'
$secure_boot_file|cut -d' ' -f 5)
-        setup_mode_byte=$(hexdump -v -e '/1 "%d\ "'
$setup_mode_file|cut -d' ' -f 5)
-
-        if [ "$secure_boot_byte" = "1" ] && [
"$setup_mode_byte" = "0" ]; then
-            return 0
-        fi
+    if [ "$arch_name" == "x86_64" ]; then
+        return 0
     fi
 
     return 1
diff --git a/kdumpctl b/kdumpctl
index 2d21a416deb1..d1c987773cf9 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -678,11 +678,9 @@ load_kdump()
 	KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
 	KDUMP_COMMANDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}"
"${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
 
-	# For secureboot enabled machines, use new kexec file based syscall.
-	# Old syscall will always fail as it does not have capability to
-	# to kernel signature verification.
-	if is_secure_boot_enforced; then
-		echo "Secure Boot is enabled. Using kexec file based syscall."
+	# On x86_64 machine, lets use kexec file based syscall by default.
+	if use_kexec_file_load; then
+		echo "Using kexec file based syscall."
 		KEXEC_ARGS="$KEXEC_ARGS -s"
 	fi
 
@@ -1162,7 +1160,7 @@ stop_fadump()
 
 stop_kdump()
 {
-	if is_secure_boot_enforced; then
+	if use_kexec_file_load; then
 		$KEXEC -s -p -u
 	else
 		$KEXEC -p -u
-- 
2.17.1

[Bhupesh Sharma]

Hi Lianbo,

Thanks for the patch. I have several nitpicks/comments, please see below:

Can you please also capture the change history, i.e. what changed from
v1 -> v2 -> v3 of the patch.

On Tue, Dec 17, 2019 at 7:50 AM Lianbo Jiang <lijiang(a)redhat.com&gt; wrote:
>  UEFI Secure boot is a signature verification mechanism, is designed to
>  prevent malicious code being loaded and executed at the early boot stage.
>  This makes sure that code executed is trusted by firmware.
>
>  Previously, with kexec_file_load() interface, kernel prevents unsigned
>  kernel image from being loaded if secure boot is enabled. So kdump will
>  detect whether secure boot is enabled firstly, then decide which interface
>  is chosen to execute, kexec_load() or kexec_file_load(). Otherwise unsigned
>  kernel loading will fail if secure boot enabled, and kexec_file_load() is
>  entered.
>
>  Now, the implementation of kexec_file_load() is adjusted in below commit.
>  With this change, if CONFIG_KEXEC_SIG_FORCE is not set, unsigned kernel
>  still has chance to be allowed to load under some conditions. 
s/has chance/has a chance

Tip: If you use vim to draft your git log messages you can use ':set
spell' to make sure vim prompts you for automatic spell check. For the
same add the following to your .gitconfig:

[core]
               editor = "vim -c 'setlocal spell'"

>  commit 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG into
> KEXEC_SIG
>  and KEXEC_SIG_FORCE")
>
>  And in the current fedora and RHEL, CONFIG_KEXEC_SIG_FORCE is not set, only
>  CONFIG_KEXEC_SIG and CONFIG_BZIMAGE_VERIFY_SIG are set on x86_64 by default. 
Since this patch is for Fedora, we can drop RHEL from the commit log.

>  It's time to spread kexec_file_load() onto all systems of x86_64,
> including
>  Secute-boot platforms and legacy platforms. 
s/Secute/Secure

>  Please refer to the following
>  form.
>
>  .----------------------------------------------------------------------.
>  | .                    |     signed kernel     |    unsigned kernel    |
>  |    .      types      |-----------------------|-----------------------|
>  |       .              |Secure boot|  Legacy   |Secure boot|  Legacy   |
>  |          .           |-----------|-----------|-----------|-----------|
>  | options     .        | prev| now | prev| now |     |     | prev| now |
>  |                .     |(file|(file|(only|(file| prev| now |(only|(file|
>  |                    . |load)|load)|load)|load)|     |     |load)|load)|
>  |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
>  |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
>  |SIG_FORCE is not set  |succ |succ |succ |succ |  X  |  X  |succ |succ |
>  |BZIMAGE_VERIFY_SIG=y  |     |     |     |     |     |     |     |     |
>  |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
>  |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
>  |SIG_FORCE is not set  |     |     |     |     |     |     |     |     |
>  |BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail |  X  |  X  |succ |fail |
>  |not set               |     |     |     |     |     |     |     |     |
>  |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
>  |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
>  |SIG_FORCE=y           |succ |succ |succ |fail |  X  |  X  |succ |fail |
>  |BZIMAGE_VERIFY_SIG=y  |     |     |     |     |     |     |     |     |
>  |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
>  |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
>  |SIG_FORCE=y           |     |     |     |     |     |     |     |     |
>  |BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail |  X  |  X  |succ |fail |
>  |not set               |     |     |     |     |     |     |     |     |
>  |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
>  |KEXEC_SIG is not set  |     |     |     |     |     |     |     |     |
>  |SIG_FORCE is not set  |     |     |     |     |     |     |     |     |
>  |BZIMAGE_VERIFY_SIG is |fail |fail |succ |succ |  X  |  X  |succ |succ |
>  |not set               |     |     |     |     |     |     |     |     |
>   ---------------------------------------------------------------------- 
I am not sure if its my email client rendering but the above table
appears mangled-up to me.
So, I am not sure everyone reviewinf this can make out all the
use-cases mentioned in the above table.

>  Note:
>  [1] The 'X' indicates that the 1st kernel(unsigned) can not boot when the
>      Secure boot is enabled.
>
>  Hence, in this patch, if on x86, 
s/x86/x86_64

>  lets use the kexec_file_load() only. See if
>  anything wrong happened in this case, in Fedora firstly for the time being. 
This makes sense. However, do we have a fallback in place, i.e. if the
kexec_file_load() failed (for some reason), should we fall back to
kexec_load() by default and inform the user or display an error
message and ask the user to try kexec_load() instead.

Thanks,
Bhupesh

>  Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt;
>  ---
>   dracut-early-kdump.sh |  4 ++--
>   kdump-lib.sh          | 31 +++++++++++--------------------
>   kdumpctl              | 10 ++++------
>   3 files changed, 17 insertions(+), 28 deletions(-)
>
>  diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh
>  index 69a34eb996cd..bfb923d6efa1 100755
>  --- a/dracut-early-kdump.sh
>  +++ b/dracut-early-kdump.sh
>  @@ -43,8 +43,8 @@ early_kdump_load()
>
>       EARLY_KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
>
>  -    if is_secure_boot_enforced; then
>  -        echo "Secure Boot is enabled. Using kexec file based syscall."
>  +    if use_kexec_file_load; then
>  +        echo "Using kexec file based syscall."
>           EARLY_KEXEC_ARGS="$EARLY_KEXEC_ARGS -s"
>       fi
>
>  diff --git a/kdump-lib.sh b/kdump-lib.sh
>  index f393c76b9cbb..5b6684992553 100755
>  --- a/kdump-lib.sh
>  +++ b/kdump-lib.sh
>  @@ -589,30 +589,21 @@ need_64bit_headers()
>       print (strtonum("0x" r[2]) > strtonum("0xffffffff"));
> }'`
>   }
>
>  -# Check if secure boot is being enforced.
>   #
>  -# Per Peter Jones, we need check efivar SecureBoot-$(the UUID) and
>  -# SetupMode-$(the UUID), they are both 5 bytes binary data. The first four
>  -# bytes are the attributes associated with the variable and can safely be
>  -# ignored, the last bytes are one-byte true-or-false variables. If SecureBoot
>  -# is 1 and SetupMode is 0, then secure boot is being enforced.
>  +# Currently, Secure Boot is only used on x86_64 and kernel enabled the
>  +# kexec_file_load() on x86_64 by default.
>  +# In addition, kernel also enables the option KEXEC_SIG, which makes the
>  +# kexec_file_load() syscall checks for a valid signature of the kernel
>  +# image if there is a signature(It must be valid). And the images can
>  +# still be loaded without a valid signature. So let kexec-tools change
>  +# as well.
>   #
>  -# Assume efivars is mounted at /sys/firmware/efi/efivars.
>  -is_secure_boot_enforced()
>  +use_kexec_file_load()
>   {
>  -    local secure_boot_file setup_mode_file
>  -    local secure_boot_byte setup_mode_byte
>  +    local arch_name=`uname -m`
>
>  -    secure_boot_file=$(find /sys/firmware/efi/efivars -name SecureBoot-*
> 2>/dev/null)
>  -    setup_mode_file=$(find /sys/firmware/efi/efivars -name SetupMode-* 2>/dev/null)
>  -
>  -    if [ -f "$secure_boot_file" ] && [ -f "$setup_mode_file"
> ]; then
>  -        secure_boot_byte=$(hexdump -v -e '/1 "%d\ "'
> $secure_boot_file|cut -d' ' -f 5)
>  -        setup_mode_byte=$(hexdump -v -e '/1 "%d\ "'
> $setup_mode_file|cut -d' ' -f 5)
>  -
>  -        if [ "$secure_boot_byte" = "1" ] && [
> "$setup_mode_byte" = "0" ]; then
>  -            return 0
>  -        fi
>  +    if [ "$arch_name" == "x86_64" ]; then
>  +        return 0
>       fi
>
>       return 1
>  diff --git a/kdumpctl b/kdumpctl
>  index 2d21a416deb1..d1c987773cf9 100755
>  --- a/kdumpctl
>  +++ b/kdumpctl
>  @@ -678,11 +678,9 @@ load_kdump()
>          KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
>          KDUMP_COMMANDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}"
> "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
>
>  -       # For secureboot enabled machines, use new kexec file based syscall.
>  -       # Old syscall will always fail as it does not have capability to
>  -       # to kernel signature verification.
>  -       if is_secure_boot_enforced; then
>  -               echo "Secure Boot is enabled. Using kexec file based syscall."
>  +       # On x86_64 machine, lets use kexec file based syscall by default.
>  +       if use_kexec_file_load; then
>  +               echo "Using kexec file based syscall."
>                  KEXEC_ARGS="$KEXEC_ARGS -s"
>          fi
>
>  @@ -1162,7 +1160,7 @@ stop_fadump()
>
>   stop_kdump()
>   {
>  -       if is_secure_boot_enforced; then
>  +       if use_kexec_file_load; then
>                  $KEXEC -s -p -u
>          else
>                  $KEXEC -p -u
>  --
>  2.17.1
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[lijiang]

在 2019年12月17日 12:57, Bhupesh Sharma 写道:
>  Hi Lianbo,
>  
>  Thanks for the patch. I have several nitpicks/comments, please see below:
>  
>  Can you please also capture the change history, i.e. what changed from
>  v1 -> v2 -> v3 of the patch.
>   
Sure. Thanks for your comment.

>  On Tue, Dec 17, 2019 at 7:50 AM Lianbo Jiang
> <lijiang(a)redhat.com&gt; wrote:
> >
> > UEFI Secure boot is a signature verification mechanism, is designed to
> > prevent malicious code being loaded and executed at the early boot stage.
> > This makes sure that code executed is trusted by firmware.
> >
> > Previously, with kexec_file_load() interface, kernel prevents unsigned
> > kernel image from being loaded if secure boot is enabled. So kdump will
> > detect whether secure boot is enabled firstly, then decide which interface
> > is chosen to execute, kexec_load() or kexec_file_load(). Otherwise unsigned
> > kernel loading will fail if secure boot enabled, and kexec_file_load() is
> > entered.
> >
> > Now, the implementation of kexec_file_load() is adjusted in below commit.
> > With this change, if CONFIG_KEXEC_SIG_FORCE is not set, unsigned kernel
> > still has chance to be allowed to load under some conditions.
>  
>  s/has chance/has a chance
>  
>  Tip: If you use vim to draft your git log messages you can use ':set
>  spell' to make sure vim prompts you for automatic spell check. For the
>  same add the following to your .gitconfig:
>  
>  [core]
>                 editor = "vim -c 'setlocal spell'"
>   
Thank you for telling me about that. I enabled the automatic spell check but I
really ignore it, so sorry for this.

> > commit 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG
> into KEXEC_SIG
> > and KEXEC_SIG_FORCE")
> >
> > And in the current fedora and RHEL, CONFIG_KEXEC_SIG_FORCE is not set, only
> > CONFIG_KEXEC_SIG and CONFIG_BZIMAGE_VERIFY_SIG are set on x86_64 by default.
>  
>  Since this patch is for Fedora, we can drop RHEL from the commit log.
>   
OK. Looks better.

> > It's time to spread kexec_file_load() onto all systems of
> x86_64, including
> > Secute-boot platforms and legacy platforms.
>  
>  s/Secute/Secure
>   
Yes. Thank you for pointing out this. 

> > Please refer to the following
> > form.
> >
> > .----------------------------------------------------------------------.
> > | .                    |     signed kernel     |    unsigned kernel    |
> > |    .      types      |-----------------------|-----------------------|
> > |       .              |Secure boot|  Legacy   |Secure boot|  Legacy   |
> > |          .           |-----------|-----------|-----------|-----------|
> > | options     .        | prev| now | prev| now |     |     | prev| now |
> > |                .     |(file|(file|(only|(file| prev| now |(only|(file|
> > |                    . |load)|load)|load)|load)|     |     |load)|load)|
> > |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
> > |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
> > |SIG_FORCE is not set  |succ |succ |succ |succ |  X  |  X  |succ |succ |
> > |BZIMAGE_VERIFY_SIG=y  |     |     |     |     |     |     |     |     |
> > |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
> > |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
> > |SIG_FORCE is not set  |     |     |     |     |     |     |     |     |
> > |BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail |  X  |  X  |succ |fail |
> > |not set               |     |     |     |     |     |     |     |     |
> > |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
> > |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
> > |SIG_FORCE=y           |succ |succ |succ |fail |  X  |  X  |succ |fail |
> > |BZIMAGE_VERIFY_SIG=y  |     |     |     |     |     |     |     |     |
> > |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
> > |KEXEC_SIG=y           |     |     |     |     |     |     |     |     |
> > |SIG_FORCE=y           |     |     |     |     |     |     |     |     |
> > |BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail |  X  |  X  |succ |fail |
> > |not set               |     |     |     |     |     |     |     |     |
> > |----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
> > |KEXEC_SIG is not set  |     |     |     |     |     |     |     |     |
> > |SIG_FORCE is not set  |     |     |     |     |     |     |     |     |
> > |BZIMAGE_VERIFY_SIG is |fail |fail |succ |succ |  X  |  X  |succ |succ |
> > |not set               |     |     |     |     |     |     |     |     |
> >  ----------------------------------------------------------------------
>  
>  I am not sure if its my email client rendering but the above table
>  appears mangled-up to me. 
It should be an email client issue. Or can you try to have a look via the
Zimbra mail? http://mail.corp.redhat.com/

>  So, I am not sure everyone reviewinf this can make out all the
>  use-cases mentioned in the above table.
>  
> > Note:
> > [1] The 'X' indicates that the 1st kernel(unsigned) can not boot when the
> >     Secure boot is enabled.
> >
> > Hence, in this patch, if on x86,
>  
>  s/x86/x86_64
>  Exactly. 
> > lets use the kexec_file_load() only. See if
> > anything wrong happened in this case, in Fedora firstly for the time being.
>  
>  This makes sense. However, do we have a fallback in place, i.e. if the
>  kexec_file_load() failed (for some reason), should we fall back to 
If the kexec_file_load() failed in the default options case, it should be a bug.

Personally think that no need to fall back to kexec_load().

>  kexec_load() by default and inform the user or display an error
>  message and ask the user to try kexec_load() instead.
>   
This should be better. I made a draft patch as follow. What's your opinion?

diff --git a/kdumpctl b/kdumpctl
index d1c987773cf9..4e8d8dab49a0 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -675,6 +675,7 @@ check_rebuild()
 # as the currently running kernel.
 load_kdump()
 {
+       local kexec_args=""
        KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
        KDUMP_COMMANDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}"
"${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
 
@@ -692,6 +693,10 @@ load_kdump()
                return 0
        else
                echo "kexec: failed to load kdump kernel" >&2
+               kexec_args=`echo $KEXEC_ARGS |grep "\-s"`
+               if [ -n "$kexec_args" ]; then
+                       echo "kexec_file_load() failed, please try kexec_load()"
>&2
+               fi
                return 1
        fi
 }

Thanks.
Lianbo

>  Thanks,
>  Bhupesh
>  
> > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt;
> > ---
> >  dracut-early-kdump.sh |  4 ++--
> >  kdump-lib.sh          | 31 +++++++++++--------------------
> >  kdumpctl              | 10 ++++------
> >  3 files changed, 17 insertions(+), 28 deletions(-)
> >
> > diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh
> > index 69a34eb996cd..bfb923d6efa1 100755
> > --- a/dracut-early-kdump.sh
> > +++ b/dracut-early-kdump.sh
> > @@ -43,8 +43,8 @@ early_kdump_load()
> >
> >      EARLY_KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
> >
> > -    if is_secure_boot_enforced; then
> > -        echo "Secure Boot is enabled. Using kexec file based syscall."
> > +    if use_kexec_file_load; then
> > +        echo "Using kexec file based syscall."
> >          EARLY_KEXEC_ARGS="$EARLY_KEXEC_ARGS -s"
> >      fi
> >
> > diff --git a/kdump-lib.sh b/kdump-lib.sh
> > index f393c76b9cbb..5b6684992553 100755
> > --- a/kdump-lib.sh
> > +++ b/kdump-lib.sh
> > @@ -589,30 +589,21 @@ need_64bit_headers()
> >      print (strtonum("0x" r[2]) > strtonum("0xffffffff"));
> }'`
> >  }
> >
> > -# Check if secure boot is being enforced.
> >  #
> > -# Per Peter Jones, we need check efivar SecureBoot-$(the UUID) and
> > -# SetupMode-$(the UUID), they are both 5 bytes binary data. The first four
> > -# bytes are the attributes associated with the variable and can safely be
> > -# ignored, the last bytes are one-byte true-or-false variables. If SecureBoot
> > -# is 1 and SetupMode is 0, then secure boot is being enforced.
> > +# Currently, Secure Boot is only used on x86_64 and kernel enabled the
> > +# kexec_file_load() on x86_64 by default.
> > +# In addition, kernel also enables the option KEXEC_SIG, which makes the
> > +# kexec_file_load() syscall checks for a valid signature of the kernel
> > +# image if there is a signature(It must be valid). And the images can
> > +# still be loaded without a valid signature. So let kexec-tools change
> > +# as well.
> >  #
> > -# Assume efivars is mounted at /sys/firmware/efi/efivars.
> > -is_secure_boot_enforced()
> > +use_kexec_file_load()
> >  {
> > -    local secure_boot_file setup_mode_file
> > -    local secure_boot_byte setup_mode_byte
> > +    local arch_name=`uname -m`
> >
> > -    secure_boot_file=$(find /sys/firmware/efi/efivars -name SecureBoot-*
> 2>/dev/null)
> > -    setup_mode_file=$(find /sys/firmware/efi/efivars -name SetupMode-*
> 2>/dev/null)
> > -
> > -    if [ -f "$secure_boot_file" ] && [ -f
> "$setup_mode_file" ]; then
> > -        secure_boot_byte=$(hexdump -v -e '/1 "%d\ "'
> $secure_boot_file|cut -d' ' -f 5)
> > -        setup_mode_byte=$(hexdump -v -e '/1 "%d\ "'
> $setup_mode_file|cut -d' ' -f 5)
> > -
> > -        if [ "$secure_boot_byte" = "1" ] && [
> "$setup_mode_byte" = "0" ]; then
> > -            return 0
> > -        fi
> > +    if [ "$arch_name" == "x86_64" ]; then
> > +        return 0
> >      fi
> >
> >      return 1
> > diff --git a/kdumpctl b/kdumpctl
> > index 2d21a416deb1..d1c987773cf9 100755
> > --- a/kdumpctl
> > +++ b/kdumpctl
> > @@ -678,11 +678,9 @@ load_kdump()
> >         KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
> >         KDUMP_COMMANDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}"
> "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
> >
> > -       # For secureboot enabled machines, use new kexec file based syscall.
> > -       # Old syscall will always fail as it does not have capability to
> > -       # to kernel signature verification.
> > -       if is_secure_boot_enforced; then
> > -               echo "Secure Boot is enabled. Using kexec file based
> syscall."
> > +       # On x86_64 machine, lets use kexec file based syscall by default.
> > +       if use_kexec_file_load; then
> > +               echo "Using kexec file based syscall."
> >                 KEXEC_ARGS="$KEXEC_ARGS -s"
> >         fi
> >
> > @@ -1162,7 +1160,7 @@ stop_fadump()
> >
> >  stop_kdump()
> >  {
> > -       if is_secure_boot_enforced; then
> > +       if use_kexec_file_load; then
> >                 $KEXEC -s -p -u
> >         else
> >                 $KEXEC -p -u
> > --
> > 2.17.1
> > _______________________________________________
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>