linux-kernel - [PATCH 01/15] percpu: fix pcpu_alloc

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]

Message-Id: <1408726399-4436-2-git-send-email-tj@kernel.org>
Date:	Fri, 22 Aug 2014 12:53:05 -0400
From:	Tejun Heo <tj@...nel.org>
To:	akpm@...ux-foundation.org, cl@...ux-foundation.org
Cc:	laijs@...fujitsu.com, linux-kernel@...r.kernel.org,
	vgoyal@...hat.com, Tejun Heo <tj@...nel.org>,
	stable@...r.kernel.org
Subject: [PATCH 01/15] percpu: fix pcpu_alloc_pages() failure path

When pcpu_alloc_pages() fails midway, pcpu_free_pages() is invoked to
free what has already been allocated.  The invocation is across the
whole requested range and pcpu_free_pages() will try to free all
non-NULL pages; unfortunately, this is incorrect as
pcpu_get_pages_and_bitmap(), unlike what its comment suggests, doesn't
clear the pages array and thus the array may have entries from the
previous invocations making the partial failure path free incorrect
pages.

Fix it by open-coding the partial freeing of the already allocated
pages.

Signed-off-by: Tejun Heo <tj@...nel.org>
Cc: stable@...r.kernel.org
---
 mm/percpu-vm.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 3707c71..8d9bb2c 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -108,7 +108,7 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
 			    int page_start, int page_end)
 {
 	const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
-	unsigned int cpu;
+	unsigned int cpu, tcpu;
 	int i;
 
 	for_each_possible_cpu(cpu) {
@@ -116,14 +116,23 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
 			struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
 
 			*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
-			if (!*pagep) {
-				pcpu_free_pages(chunk, pages, populated,
-						page_start, page_end);
-				return -ENOMEM;
-			}
+			if (!*pagep)
+				goto err;
 		}
 	}
 	return 0;
+
+err:
+	while (--i >= page_start)
+		__free_page(pages[pcpu_page_idx(cpu, i)]);
+
+	for_each_possible_cpu(tcpu) {
+		if (tcpu == cpu)
+			break;
+		for (i = page_start; i < page_end; i++)
+			__free_page(pages[pcpu_page_idx(tcpu, i)]);
+	}
+	return -ENOMEM;
 }
 
 /**
-- 
1.9.3

--
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/