include/nuttx/sched.h: Add storage for a previous signal mask. arch/: In all syscall implemenations, block all signals before dispatching a system call; resotre signal mask when the system call returnes.

arch/arm/src/armv6-m/up_svcall.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/armv6-m/up_svcall.c
  *
- *   Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2014, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -46,6 +46,7 @@
 
 #include <arch/irq.h>
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 
 #ifdef CONFIG_LIB_SYSCALL
 #  include <syscall.h>
@@ -269,6 +270,11 @@ int up_svcall(int irq, FAR void *context, FAR void *arg)
            */
 
           regs[REG_R0]         = regs[REG_R2];
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 #endif
@@ -415,6 +421,7 @@ int up_svcall(int irq, FAR void *context, FAR void *arg)
 #ifdef CONFIG_LIB_SYSCALL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -438,6 +445,11 @@ int up_svcall(int irq, FAR void *context, FAR void *arg)
           /* Offset R0 to account for the reserved values */
 
           regs[REG_R0] -= CONFIG_SYS_RESERVED;
+
+          /* Block all signals while the system call runs */
+
+          sigfillset(&set);
+          (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_R0]);
 #endif

arch/arm/src/armv7-a/arm_syscall.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  *  arch/arm/src/armv7-a/arm_syscall.c
  *
- *   Copyright (C) 2013-2014, 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2014, 2016, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -47,6 +47,7 @@
 
 #include <arch/irq.h>
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 #include <nuttx/addrenv.h>
 
 #include "arm.h"
@@ -219,6 +220,11 @@ uint32_t *arm_syscall(uint32_t *regs)
           /* Save the new SYSCALL nesting level */
 
           rtcb->xcp.nsyscalls = index;
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 
@@ -424,6 +430,7 @@ uint32_t *arm_syscall(uint32_t *regs)
 #ifdef CONFIG_LIB_SYSCALL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -450,6 +457,11 @@ uint32_t *arm_syscall(uint32_t *regs)
           /* Offset R0 to account for the reserved values */
 
           regs[REG_R0] -= CONFIG_SYS_RESERVED;
+
+          /* Block all signals while the system call runs */
+
+          sigfillset(&set);
+          (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_R0]);
 #endif
@@ -465,6 +477,7 @@ uint32_t *arm_syscall(uint32_t *regs)
               regs[REG_SP]      = (uint32_t)rtcb->xcp.kstack + ARCH_KERNEL_STACKSIZE;
             }
 #endif
+
           /* Save the new SYSCALL nesting level */
 
           rtcb->xcp.nsyscalls   = index + 1;

arch/arm/src/armv7-m/up_svcall.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/armv7-m/up_svcall.c
  *
- *   Copyright (C) 2009, 2011-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2011-2015, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -46,6 +46,7 @@
 
 #include <arch/irq.h>
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 #include <nuttx/userspace.h>
 
 #ifdef CONFIG_LIB_SYSCALL
@@ -269,6 +270,11 @@ int up_svcall(int irq, FAR void *context, FAR void *arg)
            */
 
           regs[REG_R0]         = regs[REG_R2];
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 #endif
@@ -415,6 +421,7 @@ int up_svcall(int irq, FAR void *context, FAR void *arg)
 #ifdef CONFIG_LIB_SYSCALL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -438,6 +445,11 @@ int up_svcall(int irq, FAR void *context, FAR void *arg)
           /* Offset R0 to account for the reserved values */
 
           regs[REG_R0] -= CONFIG_SYS_RESERVED;
+
+          /* Block all signals while the system call runs */
+
+          sigfillset(&set);
+          (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_R0]);
 #endif

arch/arm/src/armv7-r/arm_syscall.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  *  arch/arm/src/armv7-r/arm_syscall.c
  *
- *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2015, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -47,6 +47,7 @@
 
 #include <arch/irq.h>
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 
 #include "arm.h"
 #include "svcall.h"
@@ -217,6 +218,11 @@ uint32_t *arm_syscall(uint32_t *regs)
           /* Save the new SYSCALL nesting level */
 
           rtcb->xcp.nsyscalls = index;
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 
@@ -351,7 +357,7 @@ uint32_t *arm_syscall(uint32_t *regs)
           regs[REG_R3]   = regs[REG_R4]; /* ucontext */
 
 #ifdef CONFIG_ARCH_KERNEL_STACK
-          /* If we are signalling a user process, then we must be operating
+          /* If we are signaling a user process, then we must be operating
            * on the kernel stack now.  We need to switch back to the user
            * stack before dispatching the signal handler to the user code.
            * The existence of an allocated kernel stack is sufficient
@@ -422,6 +428,7 @@ uint32_t *arm_syscall(uint32_t *regs)
 #ifdef CONFIG_LIB_SYSCALL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -448,6 +455,11 @@ uint32_t *arm_syscall(uint32_t *regs)
           /* Offset R0 to account for the reserved values */
 
           regs[REG_R0] -= CONFIG_SYS_RESERVED;
+
+          /* Block all signals while the system call runs */
+
+          sigfillset(&set);
+          (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_R0]);
 #endif

arch/mips/src/mips32/up_swint0.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/mips/src/mips32/up_swint0.c
  *
- *   Copyright (C) 2011-2012, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011-2012, 2015, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -46,6 +46,7 @@
 #include <debug.h>
 
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 
 #include <arch/irq.h>
 #include <arch/mips32/cp0.h>
@@ -225,6 +226,11 @@ int up_swint0(int irq, FAR void *context, FAR void *arg)
           g_current_regs[REG_EPC] = rtcb->xcp.syscall[index].sysreturn;
 #error "Missing logic -- need to restore the original mode"
           rtcb->xcp.nsyscalls   = index;
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 #endif
@@ -239,6 +245,7 @@ int up_swint0(int irq, FAR void *context, FAR void *arg)
 #ifdef CONFIG_BUILD_KERNEL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -262,6 +269,11 @@ int up_swint0(int irq, FAR void *context, FAR void *arg)
           /* Offset R0 to account for the reserved values */
 
           g_current_regs[REG_R0] -= CONFIG_SYS_RESERVED;
+
+          /* Block all signals while the system call runs */
+
+          sigfillset(&set);
+          (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_A0]);
 #endif

arch/misoc/src/lm32/lm32_swint.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/misoc/src/lm32/lm32_swint.c
  *
- *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2016. 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *           Ramtin Amin <keytwo@gmail.com>
  *
@@ -47,6 +47,7 @@
 #include <debug.h>
 
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 #include <arch/irq.h>
 
 #include "lm32.h"
@@ -226,6 +227,11 @@ int lm32_swint(int irq, FAR void *context, FAR void *arg)
           g_current_regs[REG_EPC] = rtcb->xcp.syscall[index].sysreturn;
 #error "Missing logic -- need to restore the original mode"
           rtcb->xcp.nsyscalls   = index;
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 #endif
@@ -240,6 +246,7 @@ int lm32_swint(int irq, FAR void *context, FAR void *arg)
 #ifdef CONFIG_BUILD_KERNEL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -263,6 +270,11 @@ int lm32_swint(int irq, FAR void *context, FAR void *arg)
           /* Offset R0 to account for the reserved values */
 
           g_current_regs[REG_A0] -= CONFIG_SYS_RESERVED;
+
+          /* Block all signals while the system call runs */
+
+          sigfillset(&set);
+          (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_A0]);
 #endif

arch/misoc/src/minerva/minerva_swint.c

@@ -47,6 +47,7 @@
 #include <debug.h>
 
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 #include <arch/irq.h>
 
 #include "minerva.h"
@@ -213,6 +214,11 @@ int minerva_swint(int irq, FAR void *context, FAR void *arg)
         g_current_regs[REG_CSR_MEPC] = rtcb->xcp.syscall[index].sysreturn;
 #error "Missing logic -- need to restore the original mode"
         rtcb->xcp.nsyscalls = index;
+
+        /* Restore the signal mask when the syscall returns */
+
+        (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+        sigemptyset(rtcb->sigoldmask);
       }
       break;
 #endif
@@ -227,6 +233,7 @@ int minerva_swint(int irq, FAR void *context, FAR void *arg)
 #ifdef CONFIG_BUILD_KERNEL
         FAR struct tcb_s *rtcb = sched_self();
         int index = rtcb->xcp.nsyscalls;
+        sigset_t set;
 
         /* Verify that the SYS call number is within range */
 
@@ -251,6 +258,11 @@ int minerva_swint(int irq, FAR void *context, FAR void *arg)
         /* Offset R0 to account for the reserved values */
 
         g_current_regs[REG_A0] -= CONFIG_SYS_RESERVED;
+
+        /* Block all signals while the system call runs */
+
+        sigfillset(&set);
+        (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #else
         svcerr("ERROR: Bad SYS call: %d\n", regs[REG_A0]);
 #endif

arch/risc-v/src/rv32im/up_swint.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/riscv/src/rv32im/up_swint.c
  *
- *   Copyright (C) 2011-2012, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011-2012, 2015, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -46,6 +46,7 @@
 #include <debug.h>
 
 #include <nuttx/sched.h>
+#include <nuttx/signal.h>
 
 #include <arch/irq.h>
 
@@ -223,6 +224,11 @@ int up_swint(int irq, FAR void *context, FAR void *arg)
           g_current_regs[REG_EPC] = rtcb->xcp.syscall[index].sysreturn;
 #error "Missing logic -- need to restore the original mode"
           rtcb->xcp.nsyscalls   = index;
+
+          /* Restore the signal mask when the syscall returns */
+
+          (void)nxsig_procmask(SIG_SETMASK, &rtcb->sigoldmask, NULL);
+          sigemptyset(rtcb->sigoldmask);
         }
         break;
 #endif
@@ -237,6 +243,7 @@ int up_swint(int irq, FAR void *context, FAR void *arg)
 #ifdef CONFIG_BUILD_KERNEL
           FAR struct tcb_s *rtcb = sched_self();
           int index = rtcb->xcp.nsyscalls;
+          sigset_t set;
 
           /* Verify that the SYS call number is within range */
 
@@ -262,6 +269,11 @@ int up_swint(int irq, FAR void *context, FAR void *arg)
           g_current_regs[REG_A0] -= CONFIG_SYS_RESERVED;
 #else
           svcerr("ERROR: Bad SYS call: %d\n", regs[REG_A0]);
+
+        /* Block all signals while the system call runs */
+
+        sigfillset(&set);
+        (void)nxsig_procmask(SIG_BLOCK, &set, &rtcb->sigoldmask);
 #endif
         }
         break;

include/nuttx/sched.h

@@ -675,11 +675,14 @@ struct tcb_s
 
   /* POSIX Semaphore Control Fields *********************************************/
 
-  sem_t *waitsem;                        /* Semaphore ID waiting on             */
+  FAR sem_t *waitsem;                    /* Semaphore ID waiting on             */
 
   /* POSIX Signal Control Fields ************************************************/
 
   sigset_t   sigprocmask;                /* Signals that are blocked            */
+#ifdef CONFIG_LIB_SYSCALL
+  sigset_t   sigoldmask;                 /* Signals previously blocked          */
+#endif
   sigset_t   sigwaitmask;                /* Waiting for pending signals         */
   sq_queue_t sigpendactionq;             /* List of pending signal actions      */
   sq_queue_t sigpostedq;                 /* List of posted signals              */

net/netlink/netlink_conn.c

@@ -127,8 +127,8 @@ static void netlink_notify_waiters(FAR struct netlink_conn_s *conn)
   int i;
 
   /* Notify every pending thread.  Lock the scheduler while we do this so
-   * there there is no thrashing:  All waiters will be restarted, but only
+   * that there is no thrashing:  All waiters will be restarted, but only
-   * the highest priority waiter will get to run and will receive the
+   * the highest priority waiter will get to run and it will receive the
    * response.
    */