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FAILED: patch "[PATCH] lkdtm: Fix content of section containing" failed to apply to 4.14-stable tree

PATCH [email protected] 1 participant 1 message Jan 23, 2022

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The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bc93a22a19eb2b68a16ecf04cdf4b2ed65aaf398 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <[email protected]>
Date: Fri, 8 Oct 2021 18:58:40 +0200
Subject: [PATCH] lkdtm: Fix content of section containing
lkdtm_rodata_do_nothing()

On a kernel without CONFIG_STRICT_KERNEL_RWX, running EXEC_RODATA test leads to "Illegal instruction" failure.

Looking at the content of rodata_objcopy.o, we see that the function content zeroes only:

	Disassembly of section .rodata:

	0000000000000000 <.lkdtm_rodata_do_nothing>:
	   0:	00 00 00 00 	.long 0x0

Add the contents flag in order to keep the content of the section while renaming it.

	Disassembly of section .rodata:

	0000000000000000 <.lkdtm_rodata_do_nothing>:
	   0:	4e 80 00 20 	blr
drivers/misc/lkdtm/Makefile +1 -1
index aa12097668d3..e2984ce51fe4 100644
@@ -20,7 +20,7 @@ CFLAGS_REMOVE_rodata.o		+= $(CC_FLAGS_LTO)
 
 OBJCOPYFLAGS :=
 OBJCOPYFLAGS_rodata_objcopy.o	:= \
-			--rename-section .noinstr.text=.rodata,alloc,readonly,load
+			--rename-section .noinstr.text=.rodata,alloc,readonly,load,contents
 targets += rodata.o rodata_objcopy.o
 $(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE
 	$(call if_changed,objcopy)