Kdump uses currently running kernel as default, but when currently running kernel is a debug kernel, it will consume more memory, which may cause out-of-memory and fail to collect vmcore.
Now we will try to use non-debug kernels first if possible.
Also extract the logic of determine KDUMP_KERNEL from prepare_kdump_bootinfo into a function. This function will return KDUMP_KERNEL given a kernel version.
Signed-off-by: Lichen Liu lichliu@redhat.com --- Update: v1 -> v2: - extract the logic of determine KDUMP_KERNEL from prepare_kdump_bootinfo into a function.
v2 -> v3: - remove an extra space. - remove 2 unused variable declarations. - warn when using debug kernel.
kdump-lib.sh | 67 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 49 insertions(+), 18 deletions(-)
diff --git a/kdump-lib.sh b/kdump-lib.sh index b137c89..07f5012 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -633,46 +633,77 @@ prepare_kexec_args() echo "$kexec_args" }
-# -# Detect initrd and kernel location, results are stored in global enviromental variables: -# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD -# -# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already -# and will prefer already set values so user can specify custom kernel/initramfs location -# -prepare_kdump_bootinfo() +# prepare_kdump_kernel <kdump_kernelver> +# This function return kdump_kernel given a kernel version. +prepare_kdump_kernel() { - local boot_img boot_imglist boot_dirlist boot_initrdlist - local machine_id dir img default_initrd_base var_target_initrd_dir - - if [[ -z $KDUMP_KERNELVER ]]; then - KDUMP_KERNELVER="$(uname -r)" - fi - + local kdump_kernelver=$1 + local boot_dirlist boot_imglist kdump_kernel machine_id read -r machine_id < /etc/machine-id + boot_dirlist=${KDUMP_BOOTDIR:-"/boot /boot/efi /efi /"} - boot_imglist="$KDUMP_IMG-$KDUMP_KERNELVER$KDUMP_IMG_EXT $machine_id/$KDUMP_KERNELVER/$KDUMP_IMG" + boot_imglist="$KDUMP_IMG-$kdump_kernelver$KDUMP_IMG_EXT $machine_id/$kdump_kernelver/$KDUMP_IMG"
# Use BOOT_IMAGE as reference if possible, strip the GRUB root device prefix in (hd0,gpt1) format boot_img="$(sed "s/^BOOT_IMAGE=((\S*))?(\S*) .*/\2/" /proc/cmdline)" - if [[ -n $boot_img ]]; then + if [[ "$boot_img" == *"$kdump_kernelver" ]]; then boot_imglist="$boot_img $boot_imglist" fi
for dir in $boot_dirlist; do for img in $boot_imglist; do if [[ -f "$dir/$img" ]]; then - KDUMP_KERNEL=$(echo "$dir/$img" | tr -s '/') + kdump_kernel=$(echo "$dir/$img" | tr -s '/') break 2 fi done done + echo "$kdump_kernel" +} + +# +# Detect initrd and kernel location, results are stored in global environmental variables: +# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD +# +# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already +# and will prefer already set values so user can specify custom kernel/initramfs location +# +prepare_kdump_bootinfo() +{ + local boot_initrdlist nondebug_kernelver debug_kernelver + local default_initrd_base var_target_initrd_dir + + if [[ -z $KDUMP_KERNELVER ]]; then + KDUMP_KERNELVER="$(uname -r)" + nondebug_kernelver=$(sed -n -e 's/(.*)+debug$/\1/p' <<< "$KDUMP_KERNELVER") + fi + + # Use nondebug kernel if possible, because debug kernel will consume more memory and may oom. + if [[ -n $nondebug_kernelver ]]; then + dinfo "Trying to use $nondebug_kernelver." + debug_kernelver="$KDUMP_KERNELVER" + KDUMP_KERNELVER="$nondebug_kernelver" + fi + + KDUMP_KERNEL=$(prepare_kdump_kernel "$KDUMP_KERNELVER") + + if ! [[ -e $KDUMP_KERNEL ]]; then + if [[ -n $debug_kernelver ]]; then + dinfo "Fallback to using debug kernel" + KDUMP_KERNELVER="$debug_kernelver" + KDUMP_KERNEL=$(prepare_kdump_kernel "$KDUMP_KERNELVER") + fi + fi
if ! [[ -e $KDUMP_KERNEL ]]; then derror "Failed to detect kdump kernel location" return 1 fi
+ if [[ "$KDUMP_KERNEL" == *"+debug" ]]; then + dwarn "Using debug kernel, you may need to set a larger crashkernel than the default value." + fi + # Set KDUMP_BOOTDIR to where kernel image is stored KDUMP_BOOTDIR=$(dirname "$KDUMP_KERNEL")
Hi Lichen,
There are only a few nitpicks for this version.
On Tue, Jun 07, 2022 at 03:22:27PM +0800, Lichen Liu wrote:
Kdump uses currently running kernel as default, but when currently running kernel is a debug kernel, it will consume more memory, which may cause out-of-memory and fail to collect vmcore.
Now we will try to use non-debug kernels first if possible.
Also extract the logic of determine KDUMP_KERNEL from prepare_kdump_bootinfo into a function. This function will return KDUMP_KERNEL given a kernel version.
Signed-off-by: Lichen Liu lichliu@redhat.com
Update: v1 -> v2:
- extract the logic of determine KDUMP_KERNEL from prepare_kdump_bootinfo into a function.
v2 -> v3:
- remove an extra space.
- remove 2 unused variable declarations.
- warn when using debug kernel.
kdump-lib.sh | 67 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 49 insertions(+), 18 deletions(-)
diff --git a/kdump-lib.sh b/kdump-lib.sh index b137c89..07f5012 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -633,46 +633,77 @@ prepare_kexec_args() echo "$kexec_args" }
-# -# Detect initrd and kernel location, results are stored in global enviromental variables: -# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD -# -# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already -# and will prefer already set values so user can specify custom kernel/initramfs location -# -prepare_kdump_bootinfo() +# prepare_kdump_kernel <kdump_kernelver> +# This function return kdump_kernel given a kernel version. +prepare_kdump_kernel() {
- local boot_img boot_imglist boot_dirlist boot_initrdlist
- local machine_id dir img default_initrd_base var_target_initrd_dir
- if [[ -z $KDUMP_KERNELVER ]]; then
KDUMP_KERNELVER="$(uname -r)"
- fi
- local kdump_kernelver=$1
- local boot_dirlist boot_imglist kdump_kernel machine_id
You forgot to define dir and img. Unfortunately, shellcheck currently can't catch this problem [1]
[1] https://github.com/koalaman/shellcheck/issues/351
read -r machine_id < /etc/machine-id
- boot_dirlist=${KDUMP_BOOTDIR:-"/boot /boot/efi /efi /"}
- boot_imglist="$KDUMP_IMG-$KDUMP_KERNELVER$KDUMP_IMG_EXT $machine_id/$KDUMP_KERNELVER/$KDUMP_IMG"
boot_imglist="$KDUMP_IMG-$kdump_kernelver$KDUMP_IMG_EXT $machine_id/$kdump_kernelver/$KDUMP_IMG"
# Use BOOT_IMAGE as reference if possible, strip the GRUB root device prefix in (hd0,gpt1) format boot_img="$(sed "s/^BOOT_IMAGE=((\S*))?(\S*) .*/\2/" /proc/cmdline)"
- if [[ -n $boot_img ]]; then
if [[ "$boot_img" == *"$kdump_kernelver" ]]; then boot_imglist="$boot_img $boot_imglist" fi
for dir in $boot_dirlist; do for img in $boot_imglist; do if [[ -f "$dir/$img" ]]; then
KDUMP_KERNEL=$(echo "$dir/$img" | tr -s '/')
done donekdump_kernel=$(echo "$dir/$img" | tr -s '/') break 2 fi
- echo "$kdump_kernel"
+}
+# +# Detect initrd and kernel location, results are stored in global environmental variables: +# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD +# +# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already +# and will prefer already set values so user can specify custom kernel/initramfs location +# +prepare_kdump_bootinfo() +{
- local boot_initrdlist nondebug_kernelver debug_kernelver
- local default_initrd_base var_target_initrd_dir
- if [[ -z $KDUMP_KERNELVER ]]; then
KDUMP_KERNELVER="$(uname -r)"
There is no need to use double quotation when assigning value to a variable. Double quote is used to prevent globbing and word splitting as for example when calling a function/command with arguments as explained in [2].
[2] https://www.shellcheck.net/wiki/SC2086
nondebug_kernelver=$(sed -n -e 's/\(.*\)+debug$/\1/p' <<<
"$KDUMP_KERNELVER")
- fi
- # Use nondebug kernel if possible, because debug kernel will consume more memory and may oom.
- if [[ -n $nondebug_kernelver ]]; then
dinfo "Trying to use $nondebug_kernelver."
debug_kernelver="$KDUMP_KERNELVER"
KDUMP_KERNELVER="$nondebug_kernelver"
Same here.
- fi
- KDUMP_KERNEL=$(prepare_kdump_kernel "$KDUMP_KERNELVER")
- if ! [[ -e $KDUMP_KERNEL ]]; then
if [[ -n $debug_kernelver ]]; then
dinfo "Fallback to using debug kernel"
KDUMP_KERNELVER="$debug_kernelver"
And here.
KDUMP_KERNEL=$(prepare_kdump_kernel "$KDUMP_KERNELVER")
fi
fi
if ! [[ -e $KDUMP_KERNEL ]]; then derror "Failed to detect kdump kernel location" return 1 fi
if [[ "$KDUMP_KERNEL" == *"+debug" ]]; then
dwarn "Using debug kernel, you may need to set a larger crashkernel than the default value."
fi
# Set KDUMP_BOOTDIR to where kernel image is stored KDUMP_BOOTDIR=$(dirname "$KDUMP_KERNEL")
-- 2.31.1
Hi Coiby,
Thanks for your review!
I have fixed them and sent a new version.
Best regards, Lichen
On Mon, Jun 13, 2022 at 9:50 AM Coiby Xu coxu@redhat.com wrote:
Hi Lichen,
There are only a few nitpicks for this version.
On Tue, Jun 07, 2022 at 03:22:27PM +0800, Lichen Liu wrote:
Kdump uses currently running kernel as default, but when currently running kernel is a debug kernel, it will consume more memory, which may cause out-of-memory and fail to collect vmcore.
Now we will try to use non-debug kernels first if possible.
Also extract the logic of determine KDUMP_KERNEL from prepare_kdump_bootinfo into a function. This function will return KDUMP_KERNEL given a kernel version.
Signed-off-by: Lichen Liu lichliu@redhat.com
Update: v1 -> v2:
- extract the logic of determine KDUMP_KERNEL from prepare_kdump_bootinfo into a function.
v2 -> v3:
- remove an extra space.
- remove 2 unused variable declarations.
- warn when using debug kernel.
kdump-lib.sh | 67 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 49 insertions(+), 18 deletions(-)
diff --git a/kdump-lib.sh b/kdump-lib.sh index b137c89..07f5012 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -633,46 +633,77 @@ prepare_kexec_args() echo "$kexec_args" }
-# -# Detect initrd and kernel location, results are stored in global enviromental variables: -# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD -# -# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already -# and will prefer already set values so user can specify custom kernel/initramfs location -# -prepare_kdump_bootinfo() +# prepare_kdump_kernel <kdump_kernelver> +# This function return kdump_kernel given a kernel version. +prepare_kdump_kernel() {
local boot_img boot_imglist boot_dirlist boot_initrdlist
local machine_id dir img default_initrd_base var_target_initrd_dir
if [[ -z $KDUMP_KERNELVER ]]; then
KDUMP_KERNELVER="$(uname -r)"
fi
local kdump_kernelver=$1
local boot_dirlist boot_imglist kdump_kernel machine_id
You forgot to define dir and img. Unfortunately, shellcheck currently can't catch this problem [1]
[1] https://github.com/koalaman/shellcheck/issues/351
read -r machine_id < /etc/machine-id
boot_dirlist=${KDUMP_BOOTDIR:-"/boot /boot/efi /efi /"}
boot_imglist="$KDUMP_IMG-$KDUMP_KERNELVER$KDUMP_IMG_EXT $machine_id/$KDUMP_KERNELVER/$KDUMP_IMG"
boot_imglist="$KDUMP_IMG-$kdump_kernelver$KDUMP_IMG_EXT $machine_id/$kdump_kernelver/$KDUMP_IMG" # Use BOOT_IMAGE as reference if possible, strip the GRUB root device prefix in (hd0,gpt1) format boot_img="$(sed "s/^BOOT_IMAGE=\((\S*)\)\?\(\S*\) .*/\2/" /proc/cmdline)"
if [[ -n $boot_img ]]; then
if [[ "$boot_img" == *"$kdump_kernelver" ]]; then boot_imglist="$boot_img $boot_imglist" fi for dir in $boot_dirlist; do for img in $boot_imglist; do if [[ -f "$dir/$img" ]]; then
KDUMP_KERNEL=$(echo "$dir/$img" | tr -s '/')
kdump_kernel=$(echo "$dir/$img" | tr -s '/') break 2 fi done done
echo "$kdump_kernel"
+}
+# +# Detect initrd and kernel location, results are stored in global environmental variables: +# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD +# +# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already +# and will prefer already set values so user can specify custom kernel/initramfs location +# +prepare_kdump_bootinfo() +{
local boot_initrdlist nondebug_kernelver debug_kernelver
local default_initrd_base var_target_initrd_dir
if [[ -z $KDUMP_KERNELVER ]]; then
KDUMP_KERNELVER="$(uname -r)"
There is no need to use double quotation when assigning value to a variable. Double quote is used to prevent globbing and word splitting as for example when calling a function/command with arguments as explained in [2].
[2] https://www.shellcheck.net/wiki/SC2086
nondebug_kernelver=$(sed -n -e 's/\(.*\)+debug$/\1/p' <<<
"$KDUMP_KERNELVER")
fi
# Use nondebug kernel if possible, because debug kernel will consume more memory and may oom.
if [[ -n $nondebug_kernelver ]]; then
dinfo "Trying to use $nondebug_kernelver."
debug_kernelver="$KDUMP_KERNELVER"
KDUMP_KERNELVER="$nondebug_kernelver"
Same here.
fi
KDUMP_KERNEL=$(prepare_kdump_kernel "$KDUMP_KERNELVER")
if ! [[ -e $KDUMP_KERNEL ]]; then
if [[ -n $debug_kernelver ]]; then
dinfo "Fallback to using debug kernel"
KDUMP_KERNELVER="$debug_kernelver"
And here.
KDUMP_KERNEL=$(prepare_kdump_kernel "$KDUMP_KERNELVER")
fi
fi if ! [[ -e $KDUMP_KERNEL ]]; then derror "Failed to detect kdump kernel location" return 1 fi
if [[ "$KDUMP_KERNEL" == *"+debug" ]]; then
dwarn "Using debug kernel, you may need to set a larger crashkernel than the default value."
fi
# Set KDUMP_BOOTDIR to where kernel image is stored KDUMP_BOOTDIR=$(dirname "$KDUMP_KERNEL")
-- 2.31.1
-- Best regards, Coiby