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From: Tiwei Bie <tiwei.bie@linux.dev>
To: richard@nod.at, anton.ivanov@cambridgegreys.com,
	johannes@sipsolutions.net
Cc: linux-um@lists.infradead.org, linux-kernel@vger.kernel.org,
	benjamin@sipsolutions.net, arnd@arndb.de, tiwei.btw@antgroup.com,
	tiwei.bie@linux.dev
Subject: [PATCH v4 1/8] um: Do not disable kmalloc in initial_thread_cb()
Date: Mon, 27 Oct 2025 08:18:08 +0800	[thread overview]
Message-ID: <20251027001815.1666872-2-tiwei.bie@linux.dev> (raw)
In-Reply-To: <20251027001815.1666872-1-tiwei.bie@linux.dev>

From: Tiwei Bie <tiwei.btw@antgroup.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@antgroup.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



  reply	other threads:[~2025-10-27  0:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-27  0:18 [PATCH v4 0/8] um: Add SMP support Tiwei Bie
2025-10-27  0:18 ` Tiwei Bie [this message]
2025-10-27  0:18 ` [PATCH v4 2/8] um: Turn signals_* into thread-local variables Tiwei Bie
2025-10-27  0:18 ` [PATCH v4 3/8] um: Determine sleep based on need_resched() Tiwei Bie
2025-10-27  0:18 ` [PATCH v4 4/8] um: Define timers on a per-CPU basis Tiwei Bie
2025-10-27  0:18 ` [PATCH v4 5/8] um: Add initial SMP support Tiwei Bie
2025-10-27  0:18 ` [PATCH v4 6/8] um: vdso: Remove getcpu support on x86 Tiwei Bie
2025-10-27  0:18 ` [PATCH v4 7/8] asm-generic: percpu: Add assembly guard Tiwei Bie
2025-10-27  0:18 ` [PATCH v4 8/8] um: Enable SMP support on x86 Tiwei Bie

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