commit 5abbe51a526253b9f003e9a0a195638dc882d660
author Oleg Nesterov <oleg@redhat.com> Mon Feb 01 18:46:41 2021 +0100
committer Thomas Gleixner <tglx@linutronix.de> Tue Mar 16 22:13:10 2021 +0100
tree e0f3dc2b7a5e21d1ed5349fedfbd5076f82acb1e
parent 1e28eed17697bcf343c6743f0028cc3b5dd88bf0

kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data()

Preparation for fixing get_nr_restart_syscall() on X86 for COMPAT.

Add a new helper which sets restart_block->fn and calls a dummy
arch_set_restart_data() helper.

Fixes: 609c19a385c8 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174641.GA17871@redhat.com

kernel/futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index e68db77..00febd6 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2728,14 +2728,13 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val,
 		goto out;
 
 	restart = &current->restart_block;
-	restart->fn = futex_wait_restart;
 	restart->futex.uaddr = uaddr;
 	restart->futex.val = val;
 	restart->futex.time = *abs_time;
 	restart->futex.bitset = bitset;
 	restart->futex.flags = flags | FLAGS_HAS_TIMEOUT;
 
-	ret = -ERESTART_RESTARTBLOCK;
+	ret = set_restart_fn(restart, futex_wait_restart);
 
 out:
 	if (to) {