[PATCH v6 2/9] futex: Make exit_robust_list32() unconditionally available for 64-bit kernels
From: André Almeida <andrealmeid@igalia.com>
Date: 2025-11-22 05:51:17
Also in:
linux-kselftest, lkml
Subsystem:
futex subsystem, the rest · Maintainers:
Thomas Gleixner, Ingo Molnar, Linus Torvalds
The new syscall set_robust_list2() needs to handle both 64-bit and 32-bit robust lists, but not every 64-bit platform have compat entry points. Make exit_robust_list32() unconditionally available for 64-bit kernels regardless of having a compat configuration. Signed-off-by: André Almeida <andrealmeid@igalia.com> --- kernel/futex/core.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index c99d7baab24e..136639897ff9 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c@@ -31,7 +31,6 @@ * "The futexes are also cursed." * "But they come in a choice of three flavours!" */ -#include <linux/compat.h> #include <linux/jhash.h> #include <linux/pagemap.h> #include <linux/debugfs.h>
@@ -1213,12 +1212,12 @@ static void exit_robust_list(struct task_struct *curr) } } -#ifdef CONFIG_COMPAT +#ifdef CONFIG_64BIT static void __user *futex_uaddr(struct robust_list __user *entry, compat_long_t futex_offset) { - compat_uptr_t base = ptr_to_compat(entry); - void __user *uaddr = compat_ptr(base + futex_offset); + u32 base = (u32)(unsigned long)(entry); + void __user *uaddr = (void __user *)(unsigned long)(base + futex_offset); return uaddr; }
@@ -1227,13 +1226,13 @@ static void __user *futex_uaddr(struct robust_list __user *entry, * Fetch a robust-list pointer. Bit 0 signals PI futexes: */ static inline int -fetch_robust_entry32(compat_uptr_t *uentry, struct robust_list __user **entry, - compat_uptr_t __user *head, unsigned int *pi) +fetch_robust_entry32(u32 *uentry, struct robust_list __user **entry, + u32 __user *head, unsigned int *pi) { if (get_user(*uentry, head)) return -EFAULT; - *entry = compat_ptr((*uentry) & ~1); + *entry = (void __user *)(unsigned long)((*uentry) & ~1); *pi = (unsigned int)(*uentry) & 1; return 0;
@@ -1251,8 +1250,8 @@ static void exit_robust_list32(struct task_struct *curr) struct robust_list __user *entry, *next_entry, *pending; unsigned int limit = ROBUST_LIST_LIMIT, pi, pip; unsigned int next_pi; - compat_uptr_t uentry, next_uentry, upending; - compat_long_t futex_offset; + u32 uentry, next_uentry, upending; + s32 futex_offset; int rc; /*
@@ -1412,7 +1411,7 @@ static void futex_cleanup(struct task_struct *tsk) tsk->robust_list = NULL; } -#ifdef CONFIG_COMPAT +#ifdef CONFIG_64BIT if (unlikely(tsk->robust_list32)) { exit_robust_list32(tsk); tsk->robust_list32 = NULL;
--
2.52.0