linux-kernel - [PATCH 06/10] x86/ldt: use vfree

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Message-Id: <1479474236-4139-7-git-send-email-hch@lst.de>
Date:   Fri, 18 Nov 2016 14:03:52 +0100
From:   Christoph Hellwig <hch@....de>
To:     akpm@...ux-foundation.org
Cc:     aryabinin@...tuozzo.com, joelaf@...gle.com, jszhang@...vell.com,
        chris@...is-wilson.co.uk, joaodias@...gle.com, linux-mm@...ck.org,
        linux-rt-users@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 06/10] x86/ldt: use vfree_atomic() to free ldt entries

From: Andrey Ryabinin <aryabinin@...tuozzo.com>

vfree() is going to use sleeping lock. free_ldt_struct()
may be called with disabled preemption, therefore we must
use vfree_atomic() here.

E.g. call trace:
	vfree()
	free_ldt_struct()
	destroy_context_ldt()
	__mmdrop()
	finish_task_switch()
	schedule_tail()
	ret_from_fork()

Signed-off-by: Andrey Ryabinin <aryabinin@...tuozzo.com>
---
 arch/x86/kernel/ldt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 6707039..4d12cdf 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -93,7 +93,7 @@ static void free_ldt_struct(struct ldt_struct *ldt)
 
 	paravirt_free_ldt(ldt->entries, ldt->size);
 	if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
-		vfree(ldt->entries);
+		vfree_atomic(ldt->entries);
 	else
 		free_page((unsigned long)ldt->entries);
 	kfree(ldt);
-- 
2.1.4