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Subject[PATCH 2/5] mn10300: Prevent double syscall restarts
Date
From: Al Viro <viro@ftp.linux.org.uk>

We need to make sure that only the first do_signal() to be handled on
the way out of the syscall handler will bother with syscall restarts.

We do this by setting orig_d0 to -1 as sigreturn does.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
---

arch/mn10300/kernel/signal.c | 12 +++++++++---
1 files changed, 9 insertions(+), 3 deletions(-)


diff --git a/arch/mn10300/kernel/signal.c b/arch/mn10300/kernel/signal.c
index 57178a8..4ef9925 100644
--- a/arch/mn10300/kernel/signal.c
+++ b/arch/mn10300/kernel/signal.c
@@ -432,6 +432,12 @@ give_sigsegv:
return -EFAULT;
}

+static inline void stepback(struct pt_regs *regs)
+{
+ regs->pc -= 2;
+ regs->orig_d0 = -1;
+}
+
/*
* handle the actual delivery of a signal to userspace
*/
@@ -459,7 +465,7 @@ static int handle_signal(int sig,
/* fallthrough */
case -ERESTARTNOINTR:
regs->d0 = regs->orig_d0;
- regs->pc -= 2;
+ stepback(regs);
}
}

@@ -527,12 +533,12 @@ static void do_signal(struct pt_regs *regs)
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->d0 = regs->orig_d0;
- regs->pc -= 2;
+ stepback(regs);
break;

case -ERESTART_RESTARTBLOCK:
regs->d0 = __NR_restart_syscall;
- regs->pc -= 2;
+ stepback(regs);
break;
}
}


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