linux-kernel - [PATCH v4 1/8] um: Do not disable kmalloc in initial_thread

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Message-Id: <20251027001815.1666872-2-tiwei.bie@linux.dev>
Date: Mon, 27 Oct 2025 08:18:08 +0800
From: Tiwei Bie <tiwei.bie@...ux.dev>
To: richard@....at,
	anton.ivanov@...bridgegreys.com,
	johannes@...solutions.net
Cc: linux-um@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	benjamin@...solutions.net,
	arnd@...db.de,
	tiwei.btw@...group.com,
	tiwei.bie@...ux.dev
Subject: [PATCH v4 1/8] um: Do not disable kmalloc in initial_thread_cb()

From: Tiwei Bie <tiwei.btw@...group.com>

Currently, initial_thread_cb() temporarily disables kmalloc when
it invokes the callback, allowing the callback to bypass kmalloc.
This is unnecessary for the current users of initial_thread_cb(),
and we should avoid memory allocations that are not under the
control of the UML kernel. Therefore, let's stop temporarily
disabling kmalloc in initial_thread_cb().

Signed-off-by: Tiwei Bie <tiwei.btw@...group.com>
---
 arch/um/kernel/process.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 9c9c66dc45f0..757e21185a0e 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -185,11 +185,7 @@ int copy_thread(struct task_struct * p, const struct kernel_clone_args *args)
 
 void initial_thread_cb(void (*proc)(void *), void *arg)
 {
-	int save_kmalloc_ok = kmalloc_ok;
-
-	kmalloc_ok = 0;
 	initial_thread_cb_skas(proc, arg);
-	kmalloc_ok = save_kmalloc_ok;
 }
 
 int arch_dup_task_struct(struct task_struct *dst,
-- 
2.34.1