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FAILED: patch "[PATCH] x86/build: Fix linker fill bytes quirk/incompatibility for" failed to apply to 5.15-stable tree

PATCH [email protected] 1 participant 1 message Sep 10, 2023

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The patch below does not apply to the 5.15-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]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 65e710899fd19f435f40268f3a92dfaa11f14470
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023091033-scone-precinct-e841@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 65e710899fd19f435f40268f3a92dfaa11f14470 Mon Sep 17 00:00:00 2001
From: Song Liu <[email protected]>
Date: Wed, 6 Sep 2023 10:52:15 -0700
Subject: [PATCH] x86/build: Fix linker fill bytes quirk/incompatibility for
ld.lld

With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000. Example objdump -D output:

	ffffffff82b04203:       00 00                   add    %al,(%rax)
	ffffffff82b04205:       cc                      int3
	ffffffff82b04206:       cc                      int3
	ffffffff82b04207:       00 00                   add    %al,(%rax)
	ffffffff82b04209:       cc                      int3
	ffffffff82b0420a:       cc                      int3

Replace it with ":text =0xcccccccc", so we get the following instead:

	ffffffff82b04203:       cc                      int3
	ffffffff82b04204:       cc                      int3
	ffffffff82b04205:       cc                      int3
	ffffffff82b04206:       cc                      int3
	ffffffff82b04207:       cc                      int3
	ffffffff82b04208:       cc                      int3

gcc/ld doesn't seem to have the same issue. The generated code stays the same for gcc/ld.

Fixes 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
arch/x86/kernel/vmlinux.lds.S +1 -1
index 83d41c2601d7..f15fb71f280e 100644
@@ -156,7 +156,7 @@ SECTIONS
 		ALIGN_ENTRY_TEXT_END
 		*(.gnu.warning)
 
-	} :text =0xcccc
+	} :text = 0xcccccccc
 
 	/* End of text section, which should occupy whole number of pages */
 	_etext = .;