Re: [PATCH] s390/zcrypt: optimize memory allocation in online_show()

From: Dan Carpenter
Date: Mon Jul 08 2024 - 11:59:04 EST


Hi,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/yskelg-gmail-com/s390-zcrypt-optimize-memory-allocation-in-online_show/20240626-071004
base: https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features
patch link: https://lore.kernel.org/r/20240623120147.35554-3-yskelg%40gmail.com
patch subject: [PATCH] s390/zcrypt: optimize memory allocation in online_show()
config: s390-randconfig-r081-20240707 (https://download.01.org/0day-ci/archive/20240707/202407071714.4AUEoeUD-lkp@xxxxxxxxx/config)
compiler: s390-linux-gcc (GCC) 13.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202407071714.4AUEoeUD-lkp@xxxxxxxxx/

smatch warnings:
drivers/s390/crypto/zcrypt_card.c:103 online_store() warn: iterator used outside loop: 'zq'

vim +/zq +103 drivers/s390/crypto/zcrypt_card.c

ac2b96f351d7d2 Harald Freudenberger 2018-08-17 60 static ssize_t online_store(struct device *dev,
e28d2af43614eb Ingo Tuchscherer 2016-08-25 61 struct device_attribute *attr,
e28d2af43614eb Ingo Tuchscherer 2016-08-25 62 const char *buf, size_t count)
e28d2af43614eb Ingo Tuchscherer 2016-08-25 63 {
b5adbbf896d837 Julian Wiedmann 2021-06-07 64 struct zcrypt_card *zc = dev_get_drvdata(dev);
4f2fcccdb547b0 Harald Freudenberger 2020-07-02 65 struct ap_card *ac = to_ap_card(dev);
e28d2af43614eb Ingo Tuchscherer 2016-08-25 66 struct zcrypt_queue *zq;
df6f508c68dbc6 Harald Freudenberger 2021-04-13 67 int online, id, i = 0, maxzqs = 0;
df6f508c68dbc6 Harald Freudenberger 2021-04-13 68 struct zcrypt_queue **zq_uelist = NULL;
e28d2af43614eb Ingo Tuchscherer 2016-08-25 69
e28d2af43614eb Ingo Tuchscherer 2016-08-25 70 if (sscanf(buf, "%d\n", &online) != 1 || online < 0 || online > 1)
e28d2af43614eb Ingo Tuchscherer 2016-08-25 71 return -EINVAL;
e28d2af43614eb Ingo Tuchscherer 2016-08-25 72
cfaef6516e9ac6 Ingo Franzki 2023-10-26 73 if (online && (!ac->config || ac->chkstop))
4f2fcccdb547b0 Harald Freudenberger 2020-07-02 74 return -ENODEV;
4f2fcccdb547b0 Harald Freudenberger 2020-07-02 75
e28d2af43614eb Ingo Tuchscherer 2016-08-25 76 zc->online = online;
e28d2af43614eb Ingo Tuchscherer 2016-08-25 77 id = zc->card->id;
cccd85bfb7bf67 Harald Freudenberger 2016-11-24 78
3f74eb5f78198a Harald Freudenberger 2021-10-15 79 ZCRYPT_DBF_INFO("%s card=%02x online=%d\n", __func__, id, online);
cccd85bfb7bf67 Harald Freudenberger 2016-11-24 80
df6f508c68dbc6 Harald Freudenberger 2021-04-13 81 ap_send_online_uevent(&ac->ap_dev, online);
df6f508c68dbc6 Harald Freudenberger 2021-04-13 82
e28d2af43614eb Ingo Tuchscherer 2016-08-25 83 spin_lock(&zcrypt_list_lock);
df6f508c68dbc6 Harald Freudenberger 2021-04-13 84 /*
df6f508c68dbc6 Harald Freudenberger 2021-04-13 85 * As we are in atomic context here, directly sending uevents
df6f508c68dbc6 Harald Freudenberger 2021-04-13 86 * does not work. So collect the zqueues in a dynamic array
df6f508c68dbc6 Harald Freudenberger 2021-04-13 87 * and process them after zcrypt_list_lock release. As we get/put
df6f508c68dbc6 Harald Freudenberger 2021-04-13 88 * the zqueue objects, we make sure they exist after lock release.
df6f508c68dbc6 Harald Freudenberger 2021-04-13 89 */
df6f508c68dbc6 Harald Freudenberger 2021-04-13 90 list_for_each_entry(zq, &zc->zqueues, list)
2ff6be56a27c2d Yunseong Kim 2024-06-23 91 if (!!zq->online != !!online)
df6f508c68dbc6 Harald Freudenberger 2021-04-13 92 maxzqs++;
df6f508c68dbc6 Harald Freudenberger 2021-04-13 93 if (maxzqs > 0)
2ff6be56a27c2d Yunseong Kim 2024-06-23 94 zq_uelist = kcalloc(maxzqs, sizeof(*zq_uelist), GFP_ATOMIC);
e28d2af43614eb Ingo Tuchscherer 2016-08-25 95 list_for_each_entry(zq, &zc->zqueues, list)
df6f508c68dbc6 Harald Freudenberger 2021-04-13 96 if (zcrypt_queue_force_online(zq, online))
df6f508c68dbc6 Harald Freudenberger 2021-04-13 97 if (zq_uelist) {
df6f508c68dbc6 Harald Freudenberger 2021-04-13 98 zcrypt_queue_get(zq);
df6f508c68dbc6 Harald Freudenberger 2021-04-13 99 zq_uelist[i++] = zq;
df6f508c68dbc6 Harald Freudenberger 2021-04-13 100 }
e28d2af43614eb Ingo Tuchscherer 2016-08-25 101 spin_unlock(&zcrypt_list_lock);
2ff6be56a27c2d Yunseong Kim 2024-06-23 102 while (i--) {
df6f508c68dbc6 Harald Freudenberger 2021-04-13 @103 ap_send_online_uevent(&zq->queue->ap_dev, online);
^^
zq is an invalid pointer here. It's an offset off the list head.
There used to be a "zq = zq_uelist[i];" before this function call but
the patch deleted it.

2ff6be56a27c2d Yunseong Kim 2024-06-23 104 zcrypt_queue_put(zq_uelist[i]);
df6f508c68dbc6 Harald Freudenberger 2021-04-13 105 }
df6f508c68dbc6 Harald Freudenberger 2021-04-13 106 kfree(zq_uelist);
df6f508c68dbc6 Harald Freudenberger 2021-04-13 107
e28d2af43614eb Ingo Tuchscherer 2016-08-25 108 return count;
e28d2af43614eb Ingo Tuchscherer 2016-08-25 109 }

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