From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Andrew Morton <akpm@linux-foundation.org>, arnd@arndb.de
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-arch@vger.kernel.org,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH v3 1/4] mm: Create a new system state and fix core_kernel_text()
Date: Thu, 30 Sep 2021 13:23:43 +0200 [thread overview]
Message-ID: <9ecfdee7dd4d741d172cb93ff1d87f1c58127c9a.1633001016.git.christophe.leroy@csgroup.eu> (raw)
core_kernel_text() considers that until system_state in at least
SYSTEM_RUNNING, init memory is valid.
But init memory is freed a few lines before setting SYSTEM_RUNNING,
so we have a small period of time when core_kernel_text() is wrong.
Create an intermediate system state called SYSTEM_FREEING_INIT that
is set before starting freeing init memory, and use it in
core_kernel_text() to report init memory invalid earlier.
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v3: No change
v2: New
---
include/linux/kernel.h | 1 +
init/main.c | 2 ++
kernel/extable.c | 2 +-
3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2776423a587e..471bc0593679 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -248,6 +248,7 @@ extern bool early_boot_irqs_disabled;
extern enum system_states {
SYSTEM_BOOTING,
SYSTEM_SCHEDULING,
+ SYSTEM_FREEING_INITMEM,
SYSTEM_RUNNING,
SYSTEM_HALT,
SYSTEM_POWER_OFF,
diff --git a/init/main.c b/init/main.c
index 3f7216934441..c457d393fdd4 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1505,6 +1505,8 @@ static int __ref kernel_init(void *unused)
kernel_init_freeable();
/* need to finish all async __init code before freeing the memory */
async_synchronize_full();
+
+ system_state = SYSTEM_FREEING_INITMEM;
kprobe_free_init_mem();
ftrace_free_init_mem();
kgdb_free_init_mem();
diff --git a/kernel/extable.c b/kernel/extable.c
index b0ea5eb0c3b4..290661f68e6b 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -76,7 +76,7 @@ int notrace core_kernel_text(unsigned long addr)
addr < (unsigned long)_etext)
return 1;
- if (system_state < SYSTEM_RUNNING &&
+ if (system_state < SYSTEM_FREEING_INITMEM &&
init_kernel_text(addr))
return 1;
return 0;
--
2.31.1
next reply other threads:[~2021-09-30 11:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-30 11:23 Christophe Leroy [this message]
2021-09-30 11:23 ` [PATCH v3 2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says Christophe Leroy
2021-10-01 7:14 ` Daniel Axtens
2021-11-04 21:44 ` Andrew Morton
2021-11-05 17:23 ` Christophe Leroy
2021-09-30 11:23 ` [PATCH v3 3/4] powerpc: Use generic version of arch_is_kernel_initmem_freed() Christophe Leroy
2021-09-30 11:23 ` [PATCH v3 4/4] s390: " Christophe Leroy
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