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Date:   Sat, 02 Dec 2023 13:08:12 -0000
From:   "tip-bot2 for Uros Bizjak" <tip-bot2@linutronix.de>
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Subject: [tip: x86/percpu] x86/callthunks: Correct calculation of dest address
 in is_callthunk()
Cc:     Nathan Chancellor <nathan@kernel.org>,
        Uros Bizjak <ubizjak@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org
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The following commit has been merged into the x86/percpu branch of tip:

Commit-ID:     fc50065325f8b88d6986f089ae103b5db858ab96
Gitweb:        https://git.kernel.org/tip/fc50065325f8b88d6986f089ae103b5db858ab96
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Fri, 01 Dec 2023 09:57:27 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Sat, 02 Dec 2023 10:51:28 +01:00

x86/callthunks: Correct calculation of dest address in is_callthunk()

GCC didn't warn on the invalid use of relocation destination
pointer, so the calculated destination value was applied to
the uninitialized pointer location in error.

Fixes: 17bce3b2ae2d ("x86/callthunks: Handle %rip-relative relocations in call thunk template")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Closes: https://lore.kernel.org/lkml/20231201035457.GA321497@dev-arch.thelio-3990X/
Link: https://lore.kernel.org/r/20231201085727.3647051-1-ubizjak@gmail.com
---
 arch/x86/kernel/callthunks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index f56fa30..2324c7f 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -312,7 +312,7 @@ static bool is_callthunk(void *addr)
 	if (!thunks_initialized || skip_addr((void *)dest))
 		return false;
 
-	*pad = dest - tmpl_size;
+	pad = (void *)(dest - tmpl_size);
 
 	memcpy(insn_buff, skl_call_thunk_template, tmpl_size);
 	apply_relocation(insn_buff, tmpl_size, pad,