[PATCH 2/5] mn10300: prevent double syscall restarts

[PATCH 2/5] mn10300: prevent double syscall restarts

[Al Viro]

set ->orig_d0 to -1, same as what sigreturn does

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 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;
 		}
 	}
-- 
1.5.6.5

[PATCH 1/5] mn10300: Avoid SIGSEGV delivery loop

[David Howells]

From: Al Viro <viro@ftp.linux.org.uk>

Use force_sigsegv() rather than force_sig(SIGSEGV, ...) as the former resets
the SEGV handler pointer which will kill the process, rather than leaving it
open to an infinite loop if the SEGV handler itself caused a SEGV signal.

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

 arch/mn10300/kernel/signal.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)


diff --git a/arch/mn10300/kernel/signal.c b/arch/mn10300/kernel/signal.c
index 717db14..57178a8 100644
--- a/arch/mn10300/kernel/signal.c
+++ b/arch/mn10300/kernel/signal.c
@@ -345,7 +345,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 	return 0;
 
 give_sigsegv:
-	force_sig(SIGSEGV, current);
+	force_sigsegv(sig, current);
 	return -EFAULT;
 }
 
@@ -428,7 +428,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	return 0;
 
 give_sigsegv:
-	force_sig(SIGSEGV, current);
+	force_sigsegv(sig, current);
 	return -EFAULT;
 }
 

[PATCH 2/5] mn10300: Prevent double syscall restarts

[David Howells]

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;
 		}
 	}