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From: Masahiro Yamada <>
To: "K . Y . Srinivasan" <>,
	Haiyang Zhang <>,
	Stephen Hemminger <>,
	Wei Liu <>, Dexuan Cui <>,
Cc: Masahiro Yamada <>,
	Stephen Rothwell <>,
	Daniel Lezcano <>,
	Michael Kelley <>,
	Thomas Gleixner <>,
	Vitaly Kuznetsov <>,
Subject: [PATCH] clocksource: hyper-v: unexport __init-annotated hv_init_clocksource()
Date: Mon,  6 Jun 2022 14:02:38 +0900	[thread overview]
Message-ID: <> (raw)

EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization. Hence, modules cannot
use symbols annotated __init. The access to a freed symbol may end up
with kernel panic.

modpost used to detect it, but it has been broken for a decade.

Recently, I fixed modpost so it started to warn it again, then this
showed up in linux-next builds.

There are two ways to fix it:

  - Remove __init

I chose the latter for this case because the only in-tree call-site,
arch/x86/kernel/cpu/mshyperv.c is never compiled as modular.

Fixes: dd2cb348613b ("clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic")
Reported-by: Stephen Rothwell <>
Signed-off-by: Masahiro Yamada <>

 drivers/clocksource/hyperv_timer.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index ff188ab68496..bb47610bbd1c 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -565,4 +565,3 @@ void __init hv_init_clocksource(void)
 	hv_sched_clock_offset = hv_read_reference_counter();

             reply	other threads:[~2022-06-06  5:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-06  5:02 Masahiro Yamada [this message]
2022-06-06  6:59 ` Vitaly Kuznetsov
2022-06-07 20:35 ` Michael Kelley (LINUX)
2022-06-08 12:27 ` Wei Liu

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