linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Alexey Gladkov <gladkov.alexey@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>,
	io-uring@vger.kernel.org,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Linux Containers <containers@lists.linux-foundation.org>,
	linux-mm@kvack.org
Cc: Alexey Gladkov <legion@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Jann Horn <jannh@google.com>, Jens Axboe <axboe@kernel.dk>,
	Kees Cook <keescook@chromium.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>
Subject: [PATCH v7 1/7] Increase size of ucounts to atomic_long_t
Date: Mon, 22 Feb 2021 10:56:26 +0100	[thread overview]
Message-ID: <18b439960a2de06e9352c36b8d04fb149a024a86.1613987704.git.gladkov.alexey@gmail.com> (raw)
In-Reply-To: <cover.1613987704.git.gladkov.alexey@gmail.com>

RLIMIT_MSGQUEUE and RLIMIT_MEMLOCK use unsigned long to store their
counters. As a preparation for moving rlimits based on ucounts, we need
to increase the size of the variable to long.

Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
---
 include/linux/user_namespace.h |  4 ++--
 kernel/ucount.c                | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 64cf8ebdc4ec..0bb833fd41f4 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -85,7 +85,7 @@ struct user_namespace {
 	struct ctl_table_header *sysctls;
 #endif
 	struct ucounts		*ucounts;
-	int ucount_max[UCOUNT_COUNTS];
+	long ucount_max[UCOUNT_COUNTS];
 } __randomize_layout;
 
 struct ucounts {
@@ -93,7 +93,7 @@ struct ucounts {
 	struct user_namespace *ns;
 	kuid_t uid;
 	int count;
-	atomic_t ucount[UCOUNT_COUNTS];
+	atomic_long_t ucount[UCOUNT_COUNTS];
 };
 
 extern struct user_namespace init_user_ns;
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 11b1596e2542..04c561751af1 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -175,14 +175,14 @@ static void put_ucounts(struct ucounts *ucounts)
 	kfree(ucounts);
 }
 
-static inline bool atomic_inc_below(atomic_t *v, int u)
+static inline bool atomic_long_inc_below(atomic_long_t *v, int u)
 {
-	int c, old;
-	c = atomic_read(v);
+	long c, old;
+	c = atomic_long_read(v);
 	for (;;) {
 		if (unlikely(c >= u))
 			return false;
-		old = atomic_cmpxchg(v, c, c+1);
+		old = atomic_long_cmpxchg(v, c, c+1);
 		if (likely(old == c))
 			return true;
 		c = old;
@@ -196,17 +196,17 @@ struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
 	struct user_namespace *tns;
 	ucounts = get_ucounts(ns, uid);
 	for (iter = ucounts; iter; iter = tns->ucounts) {
-		int max;
+		long max;
 		tns = iter->ns;
 		max = READ_ONCE(tns->ucount_max[type]);
-		if (!atomic_inc_below(&iter->ucount[type], max))
+		if (!atomic_long_inc_below(&iter->ucount[type], max))
 			goto fail;
 	}
 	return ucounts;
 fail:
 	bad = iter;
 	for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
-		atomic_dec(&iter->ucount[type]);
+		atomic_long_dec(&iter->ucount[type]);
 
 	put_ucounts(ucounts);
 	return NULL;
@@ -216,7 +216,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
 {
 	struct ucounts *iter;
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		int dec = atomic_dec_if_positive(&iter->ucount[type]);
+		long dec = atomic_long_dec_if_positive(&iter->ucount[type]);
 		WARN_ON_ONCE(dec < 0);
 	}
 	put_ucounts(ucounts);
-- 
2.29.2



  reply	other threads:[~2021-02-22  9:57 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22  9:56 [PATCH v7 0/7] Count rlimits in each user namespace Alexey Gladkov
2021-02-22  9:56 ` Alexey Gladkov [this message]
2021-02-22  9:56 ` [PATCH v7 2/7] Add a reference to ucounts for each cred Alexey Gladkov
2021-03-01  7:32   ` e1e57d56fe: stress-ng.access.ops_per_sec -41.6% regression kernel test robot
2021-02-22  9:56 ` [PATCH v7 3/7] Reimplement RLIMIT_NPROC on top of ucounts Alexey Gladkov
2021-02-22  9:56 ` [PATCH v7 4/7] Reimplement RLIMIT_MSGQUEUE " Alexey Gladkov
2021-02-22  9:56 ` [PATCH v7 5/7] Reimplement RLIMIT_SIGPENDING " Alexey Gladkov
2021-02-24  5:18   ` d28296d248: stress-ng.sigsegv.ops_per_sec -82.7% regression kernel test robot
2021-02-24 16:54     ` Eric W. Biederman
2021-02-24 18:38       ` Alexey Gladkov
2021-02-24 18:50         ` Eric W. Biederman
2021-02-25 20:36           ` Alexey Gladkov
2021-03-05 17:56             ` Eric W. Biederman
2021-02-24 19:10         ` Linus Torvalds
2021-02-22  9:56 ` [PATCH v7 6/7] Reimplement RLIMIT_MEMLOCK on top of ucounts Alexey Gladkov
2021-03-01  6:51   ` 5b5c35b757: BUG:KASAN:use-after-free_in_dec_rlimit_ucounts kernel test robot
2021-02-22  9:56 ` [PATCH v7 7/7] kselftests: Add test to check for rlimit changes in different user namespaces Alexey Gladkov

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=18b439960a2de06e9352c36b8d04fb149a024a86.1613987704.git.gladkov.alexey@gmail.com \
    --to=gladkov.alexey@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=axboe@kernel.dk \
    --cc=christian.brauner@ubuntu.com \
    --cc=containers@lists.linux-foundation.org \
    --cc=ebiederm@xmission.com \
    --cc=io-uring@vger.kernel.org \
    --cc=jannh@google.com \
    --cc=keescook@chromium.org \
    --cc=kernel-hardening@lists.openwall.com \
    --cc=legion@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=oleg@redhat.com \
    --cc=torvalds@linux-foundation.org \
    /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: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).