[RFC PATCH 1/3] misc_cgroup: add support for nofile limit

[RFC PATCH 1/3] misc_cgroup: add support for nofile limit

[brookxu]

From: Chunguang Xu <brookxu@tencent.com>

Since the global open files are limited, in order to avoid the
abnormal behavior of some containers from generating too many
files, causing other containers to be unavailable, we need to
limit the open files of some containers.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
---
 fs/file_table.c             | 25 +++++++++++++++++++++++--
 include/linux/fs.h          |  4 +++-
 include/linux/misc_cgroup.h |  1 +
 kernel/cgroup/misc.c        |  1 +
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 45437f8e1003..a7848a4cac19 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -29,6 +29,7 @@
 #include <linux/swap.h>
 
 #include <linux/atomic.h>
+#include <linux/misc_cgroup.h>
 
 #include "internal.h"
 
@@ -53,8 +54,14 @@ static void file_free_rcu(struct rcu_head *head)
 static inline void file_free(struct file *f)
 {
 	security_file_free(f);
-	if (!(f->f_mode & FMODE_NOACCOUNT))
+	if (!(f->f_mode & FMODE_NOACCOUNT)) {
+		struct misc_cg *misc_cg = css_misc(f->f_css);
+
+		misc_cg_uncharge(MISC_CG_RES_NOFILE, misc_cg, 1);
+		put_misc_cg(misc_cg);
+
 		percpu_counter_dec(&nr_files);
+	}
 	call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
 }
 
@@ -148,8 +155,20 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
 	}
 
 	f = __alloc_file(flags, cred);
-	if (!IS_ERR(f))
+	if (!IS_ERR(f)) {
+		struct misc_cg *misc_cg = get_current_misc_cg();
+		int ret;
+
+		ret = misc_cg_try_charge(MISC_CG_RES_NOFILE, misc_cg, 1);
+		if (ret < 0) {
+			put_misc_cg(misc_cg);
+			file_free(f);
+			goto out;
+		}
+
 		percpu_counter_inc(&nr_files);
+		f->f_css = &misc_cg->css;
+	}
 
 	return f;
 
@@ -159,6 +178,7 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
 		pr_info("VFS: file-max limit %lu reached\n", get_max_files());
 		old_max = get_nr_files();
 	}
+ out:
 	return ERR_PTR(-ENFILE);
 }
 
@@ -397,4 +417,5 @@ void __init files_maxfiles_init(void)
 	n = ((nr_pages - memreserve) * (PAGE_SIZE / 1024)) / 10;
 
 	files_stat.max_files = max_t(unsigned long, n, NR_FILE);
+	misc_cg_set_capacity(MISC_CG_RES_NOFILE, files_stat.max_files);
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fad6663cd1b0..9ef3dd579ed6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -947,7 +947,9 @@ struct file {
 #endif
 	/* needed for tty driver, and maybe others */
 	void			*private_data;
-
+#ifdef CONFIG_CGROUP_MISC
+	struct cgroup_subsys_state *f_css;
+#endif
 #ifdef CONFIG_EPOLL
 	/* Used by fs/eventpoll.c to link all the hooks to this file */
 	struct hlist_head	*f_ep;
diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
index da2367e2ac1e..8450a5e66de0 100644
--- a/include/linux/misc_cgroup.h
+++ b/include/linux/misc_cgroup.h
@@ -18,6 +18,7 @@ enum misc_res_type {
 	/* AMD SEV-ES ASIDs resource */
 	MISC_CG_RES_SEV_ES,
 #endif
+	MISC_CG_RES_NOFILE,
 	MISC_CG_RES_TYPES
 };
 
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index ec02d963cad1..5d51b8eeece6 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -24,6 +24,7 @@ static const char *const misc_res_name[] = {
 	/* AMD SEV-ES ASIDs resource */
 	"sev_es",
 #endif
+	"nofile"
 };
 
 /* Root misc cgroup */
-- 
2.30.0

[RFC PATCH 1/3] misc_cgroup: add support for nofile limit

[brookxu]

From: Chunguang Xu <brookxu-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>

Since the global open files are limited, in order to avoid the
abnormal behavior of some containers from generating too many
files, causing other containers to be unavailable, we need to
limit the open files of some containers.

Signed-off-by: Chunguang Xu <brookxu-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>
---
 fs/file_table.c             | 25 +++++++++++++++++++++++--
 include/linux/fs.h          |  4 +++-
 include/linux/misc_cgroup.h |  1 +
 kernel/cgroup/misc.c        |  1 +
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 45437f8e1003..a7848a4cac19 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -29,6 +29,7 @@
 #include <linux/swap.h>
 
 #include <linux/atomic.h>
+#include <linux/misc_cgroup.h>
 
 #include "internal.h"
 
@@ -53,8 +54,14 @@ static void file_free_rcu(struct rcu_head *head)
 static inline void file_free(struct file *f)
 {
 	security_file_free(f);
-	if (!(f->f_mode & FMODE_NOACCOUNT))
+	if (!(f->f_mode & FMODE_NOACCOUNT)) {
+		struct misc_cg *misc_cg = css_misc(f->f_css);
+
+		misc_cg_uncharge(MISC_CG_RES_NOFILE, misc_cg, 1);
+		put_misc_cg(misc_cg);
+
 		percpu_counter_dec(&nr_files);
+	}
 	call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
 }
 
@@ -148,8 +155,20 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
 	}
 
 	f = __alloc_file(flags, cred);
-	if (!IS_ERR(f))
+	if (!IS_ERR(f)) {
+		struct misc_cg *misc_cg = get_current_misc_cg();
+		int ret;
+
+		ret = misc_cg_try_charge(MISC_CG_RES_NOFILE, misc_cg, 1);
+		if (ret < 0) {
+			put_misc_cg(misc_cg);
+			file_free(f);
+			goto out;
+		}
+
 		percpu_counter_inc(&nr_files);
+		f->f_css = &misc_cg->css;
+	}
 
 	return f;
 
@@ -159,6 +178,7 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
 		pr_info("VFS: file-max limit %lu reached\n", get_max_files());
 		old_max = get_nr_files();
 	}
+ out:
 	return ERR_PTR(-ENFILE);
 }
 
@@ -397,4 +417,5 @@ void __init files_maxfiles_init(void)
 	n = ((nr_pages - memreserve) * (PAGE_SIZE / 1024)) / 10;
 
 	files_stat.max_files = max_t(unsigned long, n, NR_FILE);
+	misc_cg_set_capacity(MISC_CG_RES_NOFILE, files_stat.max_files);
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fad6663cd1b0..9ef3dd579ed6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -947,7 +947,9 @@ struct file {
 #endif
 	/* needed for tty driver, and maybe others */
 	void			*private_data;
-
+#ifdef CONFIG_CGROUP_MISC
+	struct cgroup_subsys_state *f_css;
+#endif
 #ifdef CONFIG_EPOLL
 	/* Used by fs/eventpoll.c to link all the hooks to this file */
 	struct hlist_head	*f_ep;
diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
index da2367e2ac1e..8450a5e66de0 100644
--- a/include/linux/misc_cgroup.h
+++ b/include/linux/misc_cgroup.h
@@ -18,6 +18,7 @@ enum misc_res_type {
 	/* AMD SEV-ES ASIDs resource */
 	MISC_CG_RES_SEV_ES,
 #endif
+	MISC_CG_RES_NOFILE,
 	MISC_CG_RES_TYPES
 };
 
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index ec02d963cad1..5d51b8eeece6 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -24,6 +24,7 @@ static const char *const misc_res_name[] = {
 	/* AMD SEV-ES ASIDs resource */
 	"sev_es",
 #endif
+	"nofile"
 };
 
 /* Root misc cgroup */
-- 
2.30.0

[RFC PATCH 2/3] misc_cgroup: add failcnt counter

[brookxu]

From: Chunguang Xu <brookxu@tencent.com>

Instead of printing logs, we should probably track failures through
a failcnt counter, similar to mem_cgroup.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
---
 include/linux/misc_cgroup.h |  1 +
 kernel/cgroup/misc.c        | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
index 8450a5e66de0..dd1a786f39b8 100644
--- a/include/linux/misc_cgroup.h
+++ b/include/linux/misc_cgroup.h
@@ -37,6 +37,7 @@ struct misc_cg;
 struct misc_res {
 	unsigned long max;
 	atomic_long_t usage;
+	atomic_long_t failcnt;
 	bool failed;
 };
 
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index 5d51b8eeece6..7c568b619f82 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -165,6 +165,7 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
 				pr_cont("\n");
 				res->failed = true;
 			}
+			atomic_long_inc(&res->failcnt);
 			ret = -EBUSY;
 			goto err_charge;
 		}
@@ -312,6 +313,29 @@ static int misc_cg_current_show(struct seq_file *sf, void *v)
 	return 0;
 }
 
+/**
+ * misc_cg_failcnt_show() - Show the fail count of the misc cgroup.
+ * @sf: Interface file
+ * @v: Arguments passed
+ *
+ * Context: Any context.
+ * Return: 0 to denote successful print.
+ */
+static int misc_cg_failcnt_show(struct seq_file *sf, void *v)
+{
+	int i;
+	unsigned long failcnt;
+	struct misc_cg *cg = css_misc(seq_css(sf));
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		failcnt = atomic_long_read(&cg->res[i].failcnt);
+		if (READ_ONCE(misc_res_capacity[i]) || failcnt)
+			seq_printf(sf, "%s %lu\n", misc_res_name[i], failcnt);
+	}
+
+	return 0;
+}
+
 /**
  * misc_cg_capacity_show() - Show the total capacity of misc res on the host.
  * @sf: Interface file
@@ -349,6 +373,11 @@ static struct cftype misc_cg_files[] = {
 		.seq_show = misc_cg_current_show,
 		.flags = CFTYPE_NOT_ON_ROOT,
 	},
+	{
+		.name = "failcnt",
+		.seq_show = misc_cg_failcnt_show,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
 	{
 		.name = "capacity",
 		.seq_show = misc_cg_capacity_show,
@@ -383,6 +412,7 @@ misc_cg_alloc(struct cgroup_subsys_state *parent_css)
 	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
 		WRITE_ONCE(cg->res[i].max, MAX_NUM);
 		atomic_long_set(&cg->res[i].usage, 0);
+		atomic_long_set(&cg->res[i].failcnt, 0);
 	}
 
 	return &cg->css;
-- 
2.30.0

[RFC PATCH 2/3] misc_cgroup: add failcnt counter

[brookxu]

From: Chunguang Xu <brookxu-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>

Instead of printing logs, we should probably track failures through
a failcnt counter, similar to mem_cgroup.

Signed-off-by: Chunguang Xu <brookxu-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>
---
 include/linux/misc_cgroup.h |  1 +
 kernel/cgroup/misc.c        | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
index 8450a5e66de0..dd1a786f39b8 100644
--- a/include/linux/misc_cgroup.h
+++ b/include/linux/misc_cgroup.h
@@ -37,6 +37,7 @@ struct misc_cg;
 struct misc_res {
 	unsigned long max;
 	atomic_long_t usage;
+	atomic_long_t failcnt;
 	bool failed;
 };
 
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index 5d51b8eeece6..7c568b619f82 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -165,6 +165,7 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
 				pr_cont("\n");
 				res->failed = true;
 			}
+			atomic_long_inc(&res->failcnt);
 			ret = -EBUSY;
 			goto err_charge;
 		}
@@ -312,6 +313,29 @@ static int misc_cg_current_show(struct seq_file *sf, void *v)
 	return 0;
 }
 
+/**
+ * misc_cg_failcnt_show() - Show the fail count of the misc cgroup.
+ * @sf: Interface file
+ * @v: Arguments passed
+ *
+ * Context: Any context.
+ * Return: 0 to denote successful print.
+ */
+static int misc_cg_failcnt_show(struct seq_file *sf, void *v)
+{
+	int i;
+	unsigned long failcnt;
+	struct misc_cg *cg = css_misc(seq_css(sf));
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		failcnt = atomic_long_read(&cg->res[i].failcnt);
+		if (READ_ONCE(misc_res_capacity[i]) || failcnt)
+			seq_printf(sf, "%s %lu\n", misc_res_name[i], failcnt);
+	}
+
+	return 0;
+}
+
 /**
  * misc_cg_capacity_show() - Show the total capacity of misc res on the host.
  * @sf: Interface file
@@ -349,6 +373,11 @@ static struct cftype misc_cg_files[] = {
 		.seq_show = misc_cg_current_show,
 		.flags = CFTYPE_NOT_ON_ROOT,
 	},
+	{
+		.name = "failcnt",
+		.seq_show = misc_cg_failcnt_show,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
 	{
 		.name = "capacity",
 		.seq_show = misc_cg_capacity_show,
@@ -383,6 +412,7 @@ misc_cg_alloc(struct cgroup_subsys_state *parent_css)
 	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
 		WRITE_ONCE(cg->res[i].max, MAX_NUM);
 		atomic_long_set(&cg->res[i].usage, 0);
+		atomic_long_set(&cg->res[i].failcnt, 0);
 	}
 
 	return &cg->css;
-- 
2.30.0

[RFC PATCH 3/3] misc_cgroup: delete failed logs to avoid log flooding

[brookxu]

From: Chunguang Xu <brookxu@tencent.com>

Since the upper-level logic will constantly retry when it fails, in
high-stress scenarios, a large number of failure logs may affect
performance. Therefore, we can replace it with the failcnt counter.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
---
 kernel/cgroup/misc.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index 7c568b619f82..b7de0fafa48a 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -159,8 +159,6 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
 		if (new_usage > READ_ONCE(res->max) ||
 		    new_usage > READ_ONCE(misc_res_capacity[type])) {
 			if (!res->failed) {
-				pr_info("cgroup: charge rejected by the misc controller for %s resource in ",
-					misc_res_name[type]);
 				pr_cont_cgroup_path(i->css.cgroup);
 				pr_cont("\n");
 				res->failed = true;
-- 
2.30.0

[RFC PATCH 3/3] misc_cgroup: delete failed logs to avoid log flooding

[brookxu]

From: Chunguang Xu <brookxu-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>

Since the upper-level logic will constantly retry when it fails, in
high-stress scenarios, a large number of failure logs may affect
performance. Therefore, we can replace it with the failcnt counter.

Signed-off-by: Chunguang Xu <brookxu-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>
---
 kernel/cgroup/misc.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index 7c568b619f82..b7de0fafa48a 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -159,8 +159,6 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
 		if (new_usage > READ_ONCE(res->max) ||
 		    new_usage > READ_ONCE(misc_res_capacity[type])) {
 			if (!res->failed) {
-				pr_info("cgroup: charge rejected by the misc controller for %s resource in ",
-					misc_res_name[type]);
 				pr_cont_cgroup_path(i->css.cgroup);
 				pr_cont("\n");
 				res->failed = true;
-- 
2.30.0

Re: [RFC PATCH 1/3] misc_cgroup: add support for nofile limit

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 6475 bytes --]

Hi brookxu,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on cgroup/for-next]
[also build test ERROR on linux/master linus/master v5.14-rc2 next-20210722]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/brookxu/misc_cgroup-add-support-for-nofile-limit/20210722-174033
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next
config: x86_64-randconfig-a003-20210722 (attached as .config)
compiler: gcc-10 (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/5f2344b35ac15d834c4b76284f89f68c68634638
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review brookxu/misc_cgroup-add-support-for-nofile-limit/20210722-174033
        git checkout 5f2344b35ac15d834c4b76284f89f68c68634638
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   fs/file_table.c: In function 'file_free':
>> fs/file_table.c:58:29: error: implicit declaration of function 'css_misc' [-Werror=implicit-function-declaration]
      58 |   struct misc_cg *misc_cg = css_misc(f->f_css);
         |                             ^~~~~~~~
>> fs/file_table.c:58:39: error: 'struct file' has no member named 'f_css'
      58 |   struct misc_cg *misc_cg = css_misc(f->f_css);
         |                                       ^~
   fs/file_table.c: In function 'alloc_empty_file':
   fs/file_table.c:170:4: error: 'struct file' has no member named 'f_css'
     170 |   f->f_css = &misc_cg->css;
         |    ^~
>> fs/file_table.c:170:22: error: invalid use of undefined type 'struct misc_cg'
     170 |   f->f_css = &misc_cg->css;
         |                      ^~
   cc1: some warnings being treated as errors


vim +/css_misc +58 fs/file_table.c

    53	
    54	static inline void file_free(struct file *f)
    55	{
    56		security_file_free(f);
    57		if (!(f->f_mode & FMODE_NOACCOUNT)) {
  > 58			struct misc_cg *misc_cg = css_misc(f->f_css);
    59	
    60			misc_cg_uncharge(MISC_CG_RES_NOFILE, misc_cg, 1);
    61			put_misc_cg(misc_cg);
    62	
    63			percpu_counter_dec(&nr_files);
    64		}
    65		call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
    66	}
    67	
    68	/*
    69	 * Return the total number of open files in the system
    70	 */
    71	static long get_nr_files(void)
    72	{
    73		return percpu_counter_read_positive(&nr_files);
    74	}
    75	
    76	/*
    77	 * Return the maximum number of open files in the system
    78	 */
    79	unsigned long get_max_files(void)
    80	{
    81		return files_stat.max_files;
    82	}
    83	EXPORT_SYMBOL_GPL(get_max_files);
    84	
    85	/*
    86	 * Handle nr_files sysctl
    87	 */
    88	#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
    89	int proc_nr_files(struct ctl_table *table, int write,
    90	                     void *buffer, size_t *lenp, loff_t *ppos)
    91	{
    92		files_stat.nr_files = get_nr_files();
    93		return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
    94	}
    95	#else
    96	int proc_nr_files(struct ctl_table *table, int write,
    97	                     void *buffer, size_t *lenp, loff_t *ppos)
    98	{
    99		return -ENOSYS;
   100	}
   101	#endif
   102	
   103	static struct file *__alloc_file(int flags, const struct cred *cred)
   104	{
   105		struct file *f;
   106		int error;
   107	
   108		f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
   109		if (unlikely(!f))
   110			return ERR_PTR(-ENOMEM);
   111	
   112		f->f_cred = get_cred(cred);
   113		error = security_file_alloc(f);
   114		if (unlikely(error)) {
   115			file_free_rcu(&f->f_u.fu_rcuhead);
   116			return ERR_PTR(error);
   117		}
   118	
   119		atomic_long_set(&f->f_count, 1);
   120		rwlock_init(&f->f_owner.lock);
   121		spin_lock_init(&f->f_lock);
   122		mutex_init(&f->f_pos_lock);
   123		f->f_flags = flags;
   124		f->f_mode = OPEN_FMODE(flags);
   125		/* f->f_version: 0 */
   126	
   127		return f;
   128	}
   129	
   130	/* Find an unused file structure and return a pointer to it.
   131	 * Returns an error pointer if some error happend e.g. we over file
   132	 * structures limit, run out of memory or operation is not permitted.
   133	 *
   134	 * Be very careful using this.  You are responsible for
   135	 * getting write access to any mount that you might assign
   136	 * to this filp, if it is opened for write.  If this is not
   137	 * done, you will imbalance int the mount's writer count
   138	 * and a warning at __fput() time.
   139	 */
   140	struct file *alloc_empty_file(int flags, const struct cred *cred)
   141	{
   142		static long old_max;
   143		struct file *f;
   144	
   145		/*
   146		 * Privileged users can go above max_files
   147		 */
   148		if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
   149			/*
   150			 * percpu_counters are inaccurate.  Do an expensive check before
   151			 * we go and fail.
   152			 */
   153			if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files)
   154				goto over;
   155		}
   156	
   157		f = __alloc_file(flags, cred);
   158		if (!IS_ERR(f)) {
   159			struct misc_cg *misc_cg = get_current_misc_cg();
   160			int ret;
   161	
   162			ret = misc_cg_try_charge(MISC_CG_RES_NOFILE, misc_cg, 1);
   163			if (ret < 0) {
   164				put_misc_cg(misc_cg);
   165				file_free(f);
   166				goto out;
   167			}
   168	
   169			percpu_counter_inc(&nr_files);
 > 170			f->f_css = &misc_cg->css;
   171		}
   172	
   173		return f;
   174	
   175	over:
   176		/* Ran out of filps - report that */
   177		if (get_nr_files() > old_max) {
   178			pr_info("VFS: file-max limit %lu reached\n", get_max_files());
   179			old_max = get_nr_files();
   180		}
   181	 out:
   182		return ERR_PTR(-ENFILE);
   183	}
   184	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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