From: Wang Cheng <wanngchenng@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] mm/mempolicy: fix uninit-value in mpol_rebind_policy()
Date: Thu, 12 May 2022 20:34:28 +0800 [thread overview]
Message-ID: <20220512123428.fq3wofedp6oiotd4@ppc.localdomain> (raw)
mpol_set_nodemask()(mm/mempolicy.c) does not set up nodemask when
pol->mode is MPOL_LOCAL. Check pol->mode before access
pol->w.cpuset_mems_allowed in mpol_rebind_policy()(mm/mempolicy.c).
BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:352 [inline]
BUG: KMSAN: uninit-value in mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368
mpol_rebind_policy mm/mempolicy.c:352 [inline]
mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368
cpuset_change_task_nodemask kernel/cgroup/cpuset.c:1711 [inline]
cpuset_attach+0x787/0x15e0 kernel/cgroup/cpuset.c:2278
cgroup_migrate_execute+0x1023/0x1d20 kernel/cgroup/cgroup.c:2515
cgroup_migrate kernel/cgroup/cgroup.c:2771 [inline]
cgroup_attach_task+0x540/0x8b0 kernel/cgroup/cgroup.c:2804
__cgroup1_procs_write+0x5cc/0x7a0 kernel/cgroup/cgroup-v1.c:520
cgroup1_tasks_write+0x94/0xb0 kernel/cgroup/cgroup-v1.c:539
cgroup_file_write+0x4c2/0x9e0 kernel/cgroup/cgroup.c:3852
kernfs_fop_write_iter+0x66a/0x9f0 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2162 [inline]
new_sync_write fs/read_write.c:503 [inline]
vfs_write+0x1318/0x2030 fs/read_write.c:590
ksys_write+0x28b/0x510 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0xdb/0x120 fs/read_write.c:652
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
Uninit was created at:
slab_post_alloc_hook mm/slab.h:524 [inline]
slab_alloc_node mm/slub.c:3251 [inline]
slab_alloc mm/slub.c:3259 [inline]
kmem_cache_alloc+0x902/0x11c0 mm/slub.c:3264
mpol_new mm/mempolicy.c:293 [inline]
do_set_mempolicy+0x421/0xb70 mm/mempolicy.c:853
kernel_set_mempolicy mm/mempolicy.c:1504 [inline]
__do_sys_set_mempolicy mm/mempolicy.c:1510 [inline]
__se_sys_set_mempolicy+0x44c/0xb60 mm/mempolicy.c:1507
__x64_sys_set_mempolicy+0xd8/0x110 mm/mempolicy.c:1507
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
KMSAN: uninit-value in mpol_rebind_task (2)
https://syzkaller.appspot.com/bug?id=d6eb90f952c2a5de9ea718a1b873c55cb13b59dc
Reported-and-tested-by: syzbot+217f792c92599518a2ab@syzkaller.appspotmail.com
Signed-off-by: Wang Cheng <wanngchenng@gmail.com>
---
The uninit-value is pol->w.cpuset_mems_allowed in
mpol_rebind_policy().
While syzkaller reproducer runs, I notice pol->mode is 4(MPOL_LOCAL) in
mpol_set_nodemask()
do_set_mempolicy()(mm/mempolicy.c)
that `nodemask` in `pol` is not initialized, which will be accessed in
mpol_rebind_policy().
mm/mempolicy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 10e9c87260ed..18b74f02da71 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -347,7 +347,7 @@ static void mpol_rebind_preferred(struct mempolicy *pol,
*/
static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask)
{
- if (!pol)
+ if (!pol || pol->mode == MPOL_LOCAL)
return;
if (!mpol_store_user_nodemask(pol) &&
nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
--
2.30.2
next reply other threads:[~2022-05-12 12:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-12 12:34 Wang Cheng [this message]
2022-05-16 9:47 ` [PATCH] mm/mempolicy: fix uninit-value in mpol_rebind_policy() Wang Cheng
2022-05-18 0:08 ` Andrew Morton
2022-05-18 8:52 ` Dmitry Vyukov
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