From: Thomas Gleixner <tglx@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: "Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Andrè Almeida" <andrealmeid@igalia.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Carlos O'Donell" <carlos@redhat.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Florian Weimer" <fweimer@redhat.com>,
"Rich Felker" <dalias@aerifal.cx>,
"Torvald Riegel" <triegel@redhat.com>,
"Darren Hart" <dvhart@infradead.org>,
"Ingo Molnar" <mingo@kernel.org>,
"Davidlohr Bueso" <dave@stgolabs.net>,
"Arnd Bergmann" <arnd@arndb.de>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
"Uros Bizjak" <ubizjak@gmail.com>,
"Thomas Weißschuh" <linux@weissschuh.net>
Subject: [patch V4 02/14] futex: Make futex_mm_init() void
Date: Thu, 02 Apr 2026 17:21:11 +0200 [thread overview]
Message-ID: <20260402151939.731089413@kernel.org> (raw)
In-Reply-To: 20260402151131.876492985@kernel.org
Nothing fails there. Mop up the leftovers of the early version of this,
which did an allocation.
While at it clean up the stubs and the #ifdef comments to make the header
file readable.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
---
include/linux/futex.h | 28 +++++++++++-----------------
kernel/fork.c | 8 ++------
kernel/futex/core.c | 3 +--
3 files changed, 14 insertions(+), 25 deletions(-)
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -81,22 +81,20 @@ int futex_hash_prctl(unsigned long arg2,
#ifdef CONFIG_FUTEX_PRIVATE_HASH
int futex_hash_allocate_default(void);
void futex_hash_free(struct mm_struct *mm);
-int futex_mm_init(struct mm_struct *mm);
-
-#else /* !CONFIG_FUTEX_PRIVATE_HASH */
+void futex_mm_init(struct mm_struct *mm);
+#else /* CONFIG_FUTEX_PRIVATE_HASH */
static inline int futex_hash_allocate_default(void) { return 0; }
static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
-static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
-#endif /* CONFIG_FUTEX_PRIVATE_HASH */
+static inline void futex_mm_init(struct mm_struct *mm) { }
+#endif /* !CONFIG_FUTEX_PRIVATE_HASH */
-#else /* !CONFIG_FUTEX */
+#else /* CONFIG_FUTEX */
static inline void futex_init_task(struct task_struct *tsk) { }
static inline void futex_exit_recursive(struct task_struct *tsk) { }
static inline void futex_exit_release(struct task_struct *tsk) { }
static inline void futex_exec_release(struct task_struct *tsk) { }
-static inline long do_futex(u32 __user *uaddr, int op, u32 val,
- ktime_t *timeout, u32 __user *uaddr2,
- u32 val2, u32 val3)
+static inline long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
+ u32 __user *uaddr2, u32 val2, u32 val3)
{
return -EINVAL;
}
@@ -104,13 +102,9 @@ static inline int futex_hash_prctl(unsig
{
return -EINVAL;
}
-static inline int futex_hash_allocate_default(void)
-{
- return 0;
-}
+static inline int futex_hash_allocate_default(void) { return 0; }
static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
-static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
-
-#endif
+static inline void futex_mm_init(struct mm_struct *mm) { }
+#endif /* !CONFIG_FUTEX */
-#endif
+#endif /* _LINUX_FUTEX_H */
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1097,6 +1097,7 @@ static struct mm_struct *mm_init(struct
#endif
mm_init_uprobes_state(mm);
hugetlb_count_init(mm);
+ futex_mm_init(mm);
mm_flags_clear_all(mm);
if (current->mm) {
@@ -1109,11 +1110,8 @@ static struct mm_struct *mm_init(struct
mm->def_flags = 0;
}
- if (futex_mm_init(mm))
- goto fail_mm_init;
-
if (mm_alloc_pgd(mm))
- goto fail_nopgd;
+ goto fail_mm_init;
if (mm_alloc_id(mm))
goto fail_noid;
@@ -1140,8 +1138,6 @@ static struct mm_struct *mm_init(struct
mm_free_id(mm);
fail_noid:
mm_free_pgd(mm);
-fail_nopgd:
- futex_hash_free(mm);
fail_mm_init:
free_mm(mm);
return NULL;
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -1717,7 +1717,7 @@ static bool futex_ref_is_dead(struct fut
return atomic_long_read(&mm->futex_atomic) == 0;
}
-int futex_mm_init(struct mm_struct *mm)
+void futex_mm_init(struct mm_struct *mm)
{
mutex_init(&mm->futex_hash_lock);
RCU_INIT_POINTER(mm->futex_phash, NULL);
@@ -1726,7 +1726,6 @@ int futex_mm_init(struct mm_struct *mm)
mm->futex_ref = NULL;
atomic_long_set(&mm->futex_atomic, 0);
mm->futex_batches = get_state_synchronize_rcu();
- return 0;
}
void futex_hash_free(struct mm_struct *mm)
next prev parent reply other threads:[~2026-04-02 15:21 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 15:21 [patch V4 00/14] futex: Address the robust futex unlock race for real Thomas Gleixner
2026-04-02 15:21 ` [patch V4 01/14] futex: Move futex task related data into a struct Thomas Gleixner
2026-04-02 15:21 ` Thomas Gleixner [this message]
2026-04-02 15:21 ` [patch V4 03/14] futex: Move futex related mm_struct " Thomas Gleixner
2026-04-09 11:11 ` Nam Cao
2026-04-10 14:20 ` Thomas Gleixner
2026-04-02 15:21 ` [patch V4 04/14] futex: Provide UABI defines for robust list entry modifiers Thomas Gleixner
2026-04-02 15:21 ` [patch V4 05/14] uaccess: Provide unsafe_atomic_store_release_user() Thomas Gleixner
2026-04-02 15:21 ` [patch V4 06/14] x86: Select ARCH_MEMORY_ORDER_TSO Thomas Gleixner
2026-04-02 15:21 ` [patch V4 07/14] futex: Cleanup UAPI defines Thomas Gleixner
2026-04-02 15:21 ` [patch V4 08/14] futex: Add support for unlocking robust futexes Thomas Gleixner
2026-04-02 15:21 ` [patch V4 09/14] futex: Add robust futex unlock IP range Thomas Gleixner
2026-05-28 1:02 ` André Almeida
2026-05-29 21:30 ` Thomas Gleixner
2026-04-02 15:21 ` [patch V4 10/14] futex: Provide infrastructure to plug the non contended robust futex unlock race Thomas Gleixner
2026-05-28 1:08 ` André Almeida
2026-05-29 21:14 ` Thomas Gleixner
2026-04-02 15:21 ` [patch V4 11/14] x86/vdso: Prepare for robust futex unlock support Thomas Gleixner
2026-05-28 1:14 ` André Almeida
2026-04-02 15:22 ` [patch V4 12/14] x86/vdso: Implement __vdso_futex_robust_try_unlock() Thomas Gleixner
2026-04-29 8:44 ` Thomas Weißschuh
2026-05-07 9:29 ` Thomas Gleixner
2026-05-07 9:48 ` Thomas Weißschuh
2026-05-07 16:51 ` Thomas Gleixner
2026-05-29 15:36 ` André Almeida
2026-04-02 15:22 ` [patch V4 13/14] Documentation: futex: Add a note about robust list race condition Thomas Gleixner
2026-04-02 15:22 ` [patch V4 14/14] selftests: futex: Add tests for robust release operations Thomas Gleixner
2026-04-04 9:39 ` [PATCH 15/14] selftests: futex: Add tests for robust unlock within the critical section Sebastian Andrzej Siewior
2026-04-04 20:13 ` Thomas Gleixner
2026-05-22 22:16 ` André Almeida
2026-05-28 2:55 ` André Almeida
2026-05-29 21:27 ` Thomas Gleixner
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