[PATCH v1 1/2] kbuild: Mark the kernel image gzip recipes as recursive
From: Kees Cook
Date: Fri Oct 09 2026 - 02:33:31 EST
Since commit 48ebe1cbbeb51 ("kbuild: compress the kernel with pigz if
available"), cmd_gzip runs pigz through scripts/jobserver-exec, which
takes the job slots make has free. GNU Make passes the jobserver pipe
only to recipes it treats as recursive, but leaves --jobserver-auth in
MAKEFLAGS for all of them. The make 4.3 in CentOS Stream 9 also hides
the pipe in sub-makes (a backport of the fix for GNU Make bug 58232), so
jobserver-exec cannot open it, runs pigz on one thread, and prints:
WARNING: Unable to reopen jobserver read-side pipe: FileNotFoundError(2, 'No such file or directory')
Mark the gzip recipes as recursive with "+", as commit ecab4115c44cc
("kbuild: mark `rustc` (and others) invocations as recursive") did for
rustc. As with those, "make -n" now runs them.
Tested ARCH=x86_64 and ARCH=arm64 defconfig with GNU Make 4.3 plus
CentOS Stream 9's make-4.3-cloexec.patch, GCC 16.2.0, and -j64: without
this change the warning appears and pigz runs with "-p 1"; with it there
is no warning, and pigz runs with "-p 54" and "-p 64".
Reported-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/0ddb5e5e-f801-444c-aa98-0cfe814a3026@paulmck-laptop/
Fixes: 48ebe1cbbeb51 ("kbuild: compress the kernel with pigz if available")
Assisted-by: LLM
Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
---
arch/alpha/boot/Makefile | 4 ++--
arch/arc/boot/Makefile | 2 +-
arch/arm64/boot/Makefile | 2 +-
arch/microblaze/boot/Makefile | 2 +-
arch/mips/boot/Makefile | 2 +-
arch/nios2/boot/Makefile | 2 +-
arch/parisc/boot/compressed/Makefile | 2 +-
arch/riscv/boot/Makefile | 2 +-
arch/s390/boot/Makefile | 2 +-
arch/sh/boot/Makefile | 2 +-
arch/sh/boot/compressed/Makefile | 2 +-
arch/sparc/boot/Makefile | 4 ++--
arch/x86/boot/compressed/Makefile | 2 +-
arch/xtensa/boot/Makefile | 2 +-
14 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/arch/alpha/boot/Makefile b/arch/alpha/boot/Makefile
index d8dba85e606c..b050753e9015 100644
--- a/arch/alpha/boot/Makefile
+++ b/arch/alpha/boot/Makefile
@@ -40,7 +40,7 @@ endif
# Compressed kernel image
$(obj)/vmlinux.gz: $(obj)/vmlinux FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
@echo ' Kernel $@ is ready'
$(obj)/main.o: $(obj)/ksize.h
@@ -85,7 +85,7 @@ $(obj)/vmlinux.nh: vmlinux $(OBJSTRIP) FORCE
$(call if_changed,objstrip)
$(obj)/vmlinux.nh.gz: $(obj)/vmlinux.nh FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/tools/lxboot: $(obj)/bootloader $(OBJSTRIP) FORCE
$(call if_changed,objstrip)
diff --git a/arch/arc/boot/Makefile b/arch/arc/boot/Makefile
index 5a8550124b73..8a44c3e7ff3e 100644
--- a/arch/arc/boot/Makefile
+++ b/arch/arc/boot/Makefile
@@ -23,7 +23,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
$(call if_changed,objcopy)
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE
$(call if_changed,lzma)
diff --git a/arch/arm64/boot/Makefile b/arch/arm64/boot/Makefile
index b5a08333bc57..d42d07667822 100644
--- a/arch/arm64/boot/Makefile
+++ b/arch/arm64/boot/Makefile
@@ -26,7 +26,7 @@ $(obj)/Image.bz2: $(obj)/Image FORCE
$(call if_changed,bzip2)
$(obj)/Image.gz: $(obj)/Image FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/Image.lz4: $(obj)/Image FORCE
$(call if_changed,lz4)
diff --git a/arch/microblaze/boot/Makefile b/arch/microblaze/boot/Makefile
index 2b42c370d574..e3df3a64808a 100644
--- a/arch/microblaze/boot/Makefile
+++ b/arch/microblaze/boot/Makefile
@@ -14,7 +14,7 @@ $(obj)/linux.bin.ub: $(obj)/linux.bin FORCE
$(call if_changed,uimage)
$(obj)/linux.bin.gz: $(obj)/linux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
quiet_cmd_strip = STRIP $< $@$2
cmd_strip = $(STRIP) -K microblaze_start -K _end -K __log_buf \
diff --git a/arch/mips/boot/Makefile b/arch/mips/boot/Makefile
index 8473c4671702..996bf41b78de 100644
--- a/arch/mips/boot/Makefile
+++ b/arch/mips/boot/Makefile
@@ -63,7 +63,7 @@ $(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2)
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE
$(call if_changed,lzma)
diff --git a/arch/nios2/boot/Makefile b/arch/nios2/boot/Makefile
index 29c11a06b750..1381e6e428a8 100644
--- a/arch/nios2/boot/Makefile
+++ b/arch/nios2/boot/Makefile
@@ -18,7 +18,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
$(call if_changed,objcopy)
$(obj)/vmlinux.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmImage: $(obj)/vmlinux.gz FORCE
$(call if_changed,uimage)
diff --git a/arch/parisc/boot/compressed/Makefile b/arch/parisc/boot/compressed/Makefile
index 14eefb5ed5d1..a7fc7d424c00 100644
--- a/arch/parisc/boot/compressed/Makefile
+++ b/arch/parisc/boot/compressed/Makefile
@@ -55,7 +55,7 @@ suffix-$(CONFIG_KERNEL_LZO) := lzo
suffix-$(CONFIG_KERNEL_XZ) := xz
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lz4: $(obj)/vmlinux.bin FORCE
diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
index 4a2d75b7e42d..b80a077a8e8f 100644
--- a/arch/riscv/boot/Makefile
+++ b/arch/riscv/boot/Makefile
@@ -23,7 +23,7 @@ $(obj)/Image: vmlinux FORCE
$(call if_changed,objcopy)
$(obj)/Image.gz: $(obj)/Image FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/loader.o: $(src)/loader.S $(obj)/Image
diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index 10b75e053a6f..e8e43ae80dd5 100644
--- a/arch/s390/boot/Makefile
+++ b/arch/s390/boot/Makefile
@@ -117,7 +117,7 @@ suffix-$(CONFIG_KERNEL_XZ) := .xz
suffix-$(CONFIG_KERNEL_ZSTD) := .zst
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lz4: $(obj)/vmlinux.bin FORCE
diff --git a/arch/sh/boot/Makefile b/arch/sh/boot/Makefile
index 1f5d2df3c7e0..cf63e319b786 100644
--- a/arch/sh/boot/Makefile
+++ b/arch/sh/boot/Makefile
@@ -66,7 +66,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
$(call if_changed,objcopy)
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2)
diff --git a/arch/sh/boot/compressed/Makefile b/arch/sh/boot/compressed/Makefile
index 58df491778b2..b85aa5f0d616 100644
--- a/arch/sh/boot/compressed/Makefile
+++ b/arch/sh/boot/compressed/Makefile
@@ -39,7 +39,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
$(call if_changed,objcopy)
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE
diff --git a/arch/sparc/boot/Makefile b/arch/sparc/boot/Makefile
index 339c42d35089..b53cf596611e 100644
--- a/arch/sparc/boot/Makefile
+++ b/arch/sparc/boot/Makefile
@@ -23,7 +23,7 @@ ifeq ($(CONFIG_SPARC64),y)
# Actual linking
$(obj)/zImage: $(obj)/image FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
@$(kecho) 'Kernel: $@ is ready' '(#'$(or $(KBUILD_BUILD_VERSION),`cat .version`)')'
$(obj)/vmlinux.aout: vmlinux FORCE
@@ -45,7 +45,7 @@ $(obj)/image.bin: $(obj)/image FORCE
$(call if_changed,objcopy)
$(obj)/image.gz: $(obj)/image.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
UIMAGE_LOADADDR = $(CONFIG_UBOOT_LOAD_ADDR)
UIMAGE_ENTRYADDR = $(CONFIG_UBOOT_ENTRY_ADDR)
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 6ec5e031db1d..680ad803cba7 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -133,7 +133,7 @@ vmlinux.bin.all-y := $(obj)/vmlinux.bin
vmlinux.bin.all-$(CONFIG_X86_NEED_RELOCS) += $(obj)/vmlinux.relocs
$(obj)/vmlinux.bin.gz: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
$(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
diff --git a/arch/xtensa/boot/Makefile b/arch/xtensa/boot/Makefile
index d8b0fadf429a..934f9015b15f 100644
--- a/arch/xtensa/boot/Makefile
+++ b/arch/xtensa/boot/Makefile
@@ -36,7 +36,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
$(call if_changed,objcopy)
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
- $(call if_changed,gzip)
+ +$(call if_changed,gzip)
boot-elf: $(obj)/vmlinux.bin
boot-redboot: $(obj)/vmlinux.bin.gz
--
2.55.0