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From: Christoph Hellwig <hch@lst.de>
To: akpm@linux-foundation.org
Cc: aryabinin@virtuozzo.com, joelaf@google.com, jszhang@marvell.com,
	chris@chris-wilson.co.uk, joaodias@google.com,
	linux-mm@kvack.org, linux-rt-users@vger.kernel.org,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 06/10] x86/ldt: use vfree_atomic() to free ldt entries
Date: Fri, 18 Nov 2016 14:03:52 +0100	[thread overview]
Message-ID: <1479474236-4139-7-git-send-email-hch@lst.de> (raw)
In-Reply-To: <1479474236-4139-1-git-send-email-hch@lst.de>

From: Andrey Ryabinin <aryabinin@virtuozzo.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@virtuozzo.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

  parent reply	other threads:[~2016-11-18 13:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-18 13:03 reduce latency in __purge_vmap_area_lazy V2 Christoph Hellwig
2016-11-18 13:03 ` [PATCH 01/10] mm: remove free_unmap_vmap_area_noflush Christoph Hellwig
2016-11-18 13:03 ` [PATCH 02/10] mm: remove free_unmap_vmap_area_addr Christoph Hellwig
2016-11-18 13:03 ` [PATCH 03/10] mm: refactor __purge_vmap_area_lazy Christoph Hellwig
2016-11-18 13:03 ` [PATCH 04/10] mm: add vfree_atomic() Christoph Hellwig
2016-11-18 13:03 ` [PATCH 05/10] kernel/fork: use vfree_atomic() to free thread stack Christoph Hellwig
2016-11-18 13:03 ` Christoph Hellwig [this message]
2016-11-18 13:03 ` [PATCH 07/10] mm: warn about vfree from atomic context Christoph Hellwig
2016-11-22 16:35   ` Andrey Ryabinin
2016-11-23  8:39     ` Christoph Hellwig
2016-11-18 13:03 ` [PATCH 08/10] mm: mark all calls into the vmalloc subsystem as potentially sleeping Christoph Hellwig
2016-11-18 13:03 ` [PATCH 09/10] mm: turn vmap_purge_lock into a mutex Christoph Hellwig
2016-11-18 13:03 ` [PATCH 10/10] mm: add preempt points into __purge_vmap_area_lazy Christoph Hellwig

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