| 1 | From d52bcb0a807dde87057f330dbe95aa6d221a4b85 Mon Sep 17 00:00:00 2001 |
| 2 | From: =?utf-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com> |
| 3 | Date: Mon, 9 Apr 2007 17:13:02 +0700 |
| 4 | Subject: [PATCH 060/134] [ARM] Add code to prevent system calls from being restarted muliple times before returning from the kernel. |
| 5 | |
| 6 | Fixes crashes with thumb syscalls. |
| 7 | --- |
| 8 | arch/arm/kernel/signal.c | 9 +++++++++ |
| 9 | 1 files changed, 9 insertions(+), 0 deletions(-) |
| 10 | |
| 11 | --- a/arch/arm/kernel/signal.c |
| 12 | +++ b/arch/arm/kernel/signal.c |
| 13 | @@ -499,6 +499,14 @@ setup_rt_frame(int usig, struct k_sigact |
| 14 | |
| 15 | static inline void restart_syscall(struct pt_regs *regs) |
| 16 | { |
| 17 | + if (regs->ARM_ORIG_r0 == -ERESTARTNOHAND || |
| 18 | + regs->ARM_ORIG_r0 == -ERESTARTSYS || |
| 19 | + regs->ARM_ORIG_r0 == -ERESTARTNOINTR || |
| 20 | + regs->ARM_ORIG_r0 == -ERESTART_RESTARTBLOCK) { |
| 21 | + /* the syscall cannot be safely restarted, return -EINTR instead */ |
| 22 | + regs->ARM_r0 = -EINTR; |
| 23 | + return; |
| 24 | + } |
| 25 | regs->ARM_r0 = regs->ARM_ORIG_r0; |
| 26 | regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; |
| 27 | } |
| 28 | @@ -631,6 +639,7 @@ static void do_signal(struct pt_regs *re |
| 29 | */ |
| 30 | if (syscall) { |
| 31 | if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) { |
| 32 | + regs->ARM_r0 = -EAGAIN; /* prevent multiple restarts */ |
| 33 | if (thumb_mode(regs)) { |
| 34 | regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; |
| 35 | regs->ARM_pc -= 2; |
| 36 | |
