From: Yu Zhao <yuzhao@google.com> To: Seth Jennings <sjenning@redhat.com>, Dan Streetman <ddstreet@ieee.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yu Zhao <yuzhao@google.com> Subject: [PATCH v2] zswap: only use CPU notifier when HOTPLUG_CPU=y Date: Wed, 30 Nov 2016 13:15:16 -0800 [thread overview] Message-ID: <1480540516-6458-1-git-send-email-yuzhao@google.com> (raw) __unregister_cpu_notifier() only removes registered notifier from its linked list when CPU hotplug is configured. If we free registered CPU notifier when HOTPLUG_CPU=n, we corrupt the linked list. To fix the problem, we can either use a static CPU notifier that walks through each pool or just simply disable CPU notifier when CPU hotplug is not configured (which is perfectly safe because the code in question is called after all possible CPUs are online and will remain online until power off). v2: #ifdef for cpu_notifier_register_done during cleanup. Signe-off-by: Yu Zhao <yuzhao@google.com> --- mm/zswap.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/mm/zswap.c b/mm/zswap.c index 275b22c..2915f44 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -118,7 +118,9 @@ struct zswap_pool { struct kref kref; struct list_head list; struct work_struct work; +#ifdef CONFIG_HOTPLUG_CPU struct notifier_block notifier; +#endif char tfm_name[CRYPTO_MAX_ALG_NAME]; }; @@ -448,6 +450,7 @@ static int __zswap_cpu_comp_notifier(struct zswap_pool *pool, return NOTIFY_OK; } +#ifdef CONFIG_HOTPLUG_CPU static int zswap_cpu_comp_notifier(struct notifier_block *nb, unsigned long action, void *pcpu) { @@ -456,27 +459,34 @@ static int zswap_cpu_comp_notifier(struct notifier_block *nb, return __zswap_cpu_comp_notifier(pool, action, cpu); } +#endif static int zswap_cpu_comp_init(struct zswap_pool *pool) { unsigned long cpu; +#ifdef CONFIG_HOTPLUG_CPU memset(&pool->notifier, 0, sizeof(pool->notifier)); pool->notifier.notifier_call = zswap_cpu_comp_notifier; cpu_notifier_register_begin(); +#endif for_each_online_cpu(cpu) if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) == NOTIFY_BAD) goto cleanup; +#ifdef CONFIG_HOTPLUG_CPU __register_cpu_notifier(&pool->notifier); cpu_notifier_register_done(); +#endif return 0; cleanup: for_each_online_cpu(cpu) __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); +#ifdef CONFIG_HOTPLUG_CPU cpu_notifier_register_done(); +#endif return -ENOMEM; } @@ -484,11 +494,15 @@ static void zswap_cpu_comp_destroy(struct zswap_pool *pool) { unsigned long cpu; +#ifdef CONFIG_HOTPLUG_CPU cpu_notifier_register_begin(); +#endif for_each_online_cpu(cpu) __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); +#ifdef CONFIG_HOTPLUG_CPU __unregister_cpu_notifier(&pool->notifier); cpu_notifier_register_done(); +#endif } /********************************* -- 2.8.0.rc3.226.g39d4020
WARNING: multiple messages have this Message-ID (diff)
From: Yu Zhao <yuzhao@google.com> To: Seth Jennings <sjenning@redhat.com>, Dan Streetman <ddstreet@ieee.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yu Zhao <yuzhao@google.com> Subject: [PATCH v2] zswap: only use CPU notifier when HOTPLUG_CPU=y Date: Wed, 30 Nov 2016 13:15:16 -0800 [thread overview] Message-ID: <1480540516-6458-1-git-send-email-yuzhao@google.com> (raw) __unregister_cpu_notifier() only removes registered notifier from its linked list when CPU hotplug is configured. If we free registered CPU notifier when HOTPLUG_CPU=n, we corrupt the linked list. To fix the problem, we can either use a static CPU notifier that walks through each pool or just simply disable CPU notifier when CPU hotplug is not configured (which is perfectly safe because the code in question is called after all possible CPUs are online and will remain online until power off). v2: #ifdef for cpu_notifier_register_done during cleanup. Signe-off-by: Yu Zhao <yuzhao@google.com> --- mm/zswap.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/mm/zswap.c b/mm/zswap.c index 275b22c..2915f44 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -118,7 +118,9 @@ struct zswap_pool { struct kref kref; struct list_head list; struct work_struct work; +#ifdef CONFIG_HOTPLUG_CPU struct notifier_block notifier; +#endif char tfm_name[CRYPTO_MAX_ALG_NAME]; }; @@ -448,6 +450,7 @@ static int __zswap_cpu_comp_notifier(struct zswap_pool *pool, return NOTIFY_OK; } +#ifdef CONFIG_HOTPLUG_CPU static int zswap_cpu_comp_notifier(struct notifier_block *nb, unsigned long action, void *pcpu) { @@ -456,27 +459,34 @@ static int zswap_cpu_comp_notifier(struct notifier_block *nb, return __zswap_cpu_comp_notifier(pool, action, cpu); } +#endif static int zswap_cpu_comp_init(struct zswap_pool *pool) { unsigned long cpu; +#ifdef CONFIG_HOTPLUG_CPU memset(&pool->notifier, 0, sizeof(pool->notifier)); pool->notifier.notifier_call = zswap_cpu_comp_notifier; cpu_notifier_register_begin(); +#endif for_each_online_cpu(cpu) if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) == NOTIFY_BAD) goto cleanup; +#ifdef CONFIG_HOTPLUG_CPU __register_cpu_notifier(&pool->notifier); cpu_notifier_register_done(); +#endif return 0; cleanup: for_each_online_cpu(cpu) __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); +#ifdef CONFIG_HOTPLUG_CPU cpu_notifier_register_done(); +#endif return -ENOMEM; } @@ -484,11 +494,15 @@ static void zswap_cpu_comp_destroy(struct zswap_pool *pool) { unsigned long cpu; +#ifdef CONFIG_HOTPLUG_CPU cpu_notifier_register_begin(); +#endif for_each_online_cpu(cpu) __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); +#ifdef CONFIG_HOTPLUG_CPU __unregister_cpu_notifier(&pool->notifier); cpu_notifier_register_done(); +#endif } /********************************* -- 2.8.0.rc3.226.g39d4020 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next reply other threads:[~2016-11-30 21:15 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-11-30 21:15 Yu Zhao [this message] 2016-11-30 21:15 ` [PATCH v2] zswap: only use CPU notifier when HOTPLUG_CPU=y Yu Zhao 2016-12-02 13:46 ` Michal Hocko 2016-12-02 13:46 ` Michal Hocko 2016-12-02 14:24 ` Dan Streetman 2016-12-02 14:24 ` Dan Streetman 2016-12-02 14:38 ` Michal Hocko 2016-12-02 14:38 ` Michal Hocko 2016-12-02 14:44 ` Michal Hocko 2016-12-02 14:44 ` Michal Hocko 2016-12-02 14:56 ` Dan Streetman 2016-12-02 14:56 ` Dan Streetman 2016-12-02 15:19 ` [PATCH] hotplug: make register and unregister notifier API symmetric Michal Hocko 2016-12-02 15:19 ` Michal Hocko 2016-12-03 5:15 ` kbuild test robot 2016-12-05 6:08 ` Michal Hocko 2016-12-05 6:08 ` Michal Hocko 2016-12-03 7:18 ` kbuild test robot 2016-12-05 20:59 ` Yu Zhao 2016-12-05 20:59 ` Yu Zhao 2016-12-06 9:30 ` Michal Hocko 2016-12-06 9:30 ` Michal Hocko 2016-12-05 21:11 ` [PATCH v2] zswap: only use CPU notifier when HOTPLUG_CPU=y Yu Zhao 2016-12-05 21:11 ` Yu Zhao
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1480540516-6458-1-git-send-email-yuzhao@google.com \ --to=yuzhao@google.com \ --cc=ddstreet@ieee.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=sjenning@redhat.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.