linux-kernel - [PATCH 01/20] percpu: fix pcpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 21 Jul 2009 19:26:00 +0900
From:	Tejun Heo <tj@...nel.org>
To:	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
	mingo@...hat.com, benh@...nel.crashing.org, davem@...emloft.net,
	dhowells@...hat.com, npiggin@...e.de, JBeulich@...ell.com,
	cl@...ux-foundation.org, rusty@...tcorp.com.au, hpa@...or.com,
	tglx@...utronix.de, akpm@...ux-foundation.org, x86@...nel.org,
	andi@...stfloor.org
Cc:	Tejun Heo <tj@...nel.org>
Subject: [PATCH 01/20] percpu: fix pcpu_reclaim() locking

pcpu_reclaim() calls pcpu_depopulate_chunk() which makes use of pages
array and bitmap returned by pcpu_get_pages_and_bitmap() and thus
should be called under pcpu_alloc_mutex.  pcpu_reclaim() released the
mutex before calling depopulate leading to double free and other
strange problems caused by the unexpected concurrent usages of pages
array and bitmap.  Fix it.

Signed-off-by: Tejun Heo <tj@...nel.org>
---
 mm/percpu.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index f993dc8..c44a5b2 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1181,12 +1181,13 @@ static void pcpu_reclaim(struct work_struct *work)
 	}
 
 	spin_unlock_irq(&pcpu_lock);
-	mutex_unlock(&pcpu_alloc_mutex);
 
 	list_for_each_entry_safe(chunk, next, &todo, list) {
 		pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
 		free_pcpu_chunk(chunk);
 	}
+
+	mutex_unlock(&pcpu_alloc_mutex);
 }
 
 /**
-- 
1.6.0.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/