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From d52bcb0a807dde87057f330dbe95aa6d221a4b85 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com>
Date: Mon, 9 Apr 2007 17:13:02 +0700
Subject: [PATCH 060/134] [ARM] Add code to prevent system calls from being restarted muliple times before returning from the kernel.
Fixes crashes with thumb syscalls.
---
arch/arm/kernel/signal.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -534,6 +534,14 @@ setup_rt_frame(int usig, struct k_sigact
static inline void restart_syscall(struct pt_regs *regs)
{
+ if (regs->ARM_ORIG_r0 == -ERESTARTNOHAND ||
+ regs->ARM_ORIG_r0 == -ERESTARTSYS ||
+ regs->ARM_ORIG_r0 == -ERESTARTNOINTR ||
+ regs->ARM_ORIG_r0 == -ERESTART_RESTARTBLOCK) {
+ /* the syscall cannot be safely restarted, return -EINTR instead */
+ regs->ARM_r0 = -EINTR;
+ return;
+ }
regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
}
@@ -650,6 +658,7 @@ static int do_signal(sigset_t *oldset, s
*/
if (syscall) {
if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
+ regs->ARM_r0 = -EAGAIN; /* prevent multiple restarts */
if (thumb_mode(regs)) {
regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
regs->ARM_pc -= 2;
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