Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - a bit more MM

 - procfs updates

 - dynamic-debug fixes

 - lib/ updates

 - checkpatch

 - epoll

 - nilfs2

 - signals

 - rapidio

 - PID management cleanup and optimization

 - kcov updates

 - sysvipc updates

 - quite a few misc things all over the place

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
  EXPERT Kconfig menu: fix broken EXPERT menu
  include/asm-generic/topology.h: remove unused parent_node() macro
  arch/tile/include/asm/topology.h: remove unused parent_node() macro
  arch/sparc/include/asm/topology_64.h: remove unused parent_node() macro
  arch/sh/include/asm/topology.h: remove unused parent_node() macro
  arch/ia64/include/asm/topology.h: remove unused parent_node() macro
  drivers/pcmcia/sa1111_badge4.c: avoid unused function warning
  mm: add infrastructure for get_user_pages_fast() benchmarking
  sysvipc: make get_maxid O(1) again
  sysvipc: properly name ipc_addid() limit parameter
  sysvipc: duplicate lock comments wrt ipc_addid()
  sysvipc: unteach ids->next_id for !CHECKPOINT_RESTORE
  initramfs: use time64_t timestamps
  drivers/watchdog: make use of devm_register_reboot_notifier()
  kernel/reboot.c: add devm_register_reboot_notifier()
  kcov: update documentation
  Makefile: support flag -fsanitizer-coverage=trace-cmp
  kcov: support comparison operands collection
  kcov: remove pointless current != NULL check
  kernel/panic.c: add TAINT_AUX
  ...

5 files changed, 109 insertions, 8 deletions

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 12278a926370..fdf72429f801 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -18,7 +18,7 @@ shortcut for ``print_hex_dump(KERN_DEBUG)``.
 
 For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
 its ``prefix_str`` argument, if it is constant string; or ``hexdump``
-in case ``prefix_str`` is build dynamically.
+in case ``prefix_str`` is built dynamically.
 
 Dynamic debug has even more useful features:
 
@@ -197,8 +197,8 @@ line
     line number matches the callsite line number exactly.  A
     range of line numbers matches any callsite between the first
     and last line number inclusive.  An empty first number means
-    the first line in the file, an empty line number means the
-    last number in the file.  Examples::
+    the first line in the file, an empty last line number means the
+    last line number in the file.  Examples::
 
 	line 1603           // exactly line 1603
 	line 1600-1605      // the six lines from line 1600 to line 1605
diff --git a/Documentation/clearing-warn-once.txt b/Documentation/clearing-warn-once.txt
new file mode 100644
index 000000000000..5b1f5d547be1
--- /dev/null
+++ b/Documentation/clearing-warn-once.txt
@@ -0,0 +1,7 @@
+
+WARN_ONCE / WARN_ON_ONCE only print a warning once.
+
+echo 1 > /sys/kernel/debug/clear_warn_once
+
+clears the state and allows the warnings to print once again.
+This can be useful after test suite runs to reproduce problems.
diff --git a/Documentation/dev-tools/kcov.rst b/Documentation/dev-tools/kcov.rst
index 44886c91e112..c2f6452e38ed 100644
--- a/Documentation/dev-tools/kcov.rst
+++ b/Documentation/dev-tools/kcov.rst
@@ -12,19 +12,30 @@ To achieve this goal it does not collect coverage in soft/hard interrupts
 and instrumentation of some inherently non-deterministic parts of kernel is
 disabled (e.g. scheduler, locking).
 
-Usage
------
+kcov is also able to collect comparison operands from the instrumented code
+(this feature currently requires that the kernel is compiled with clang).
+
+Prerequisites
+-------------
 
 Configure the kernel with::
 
         CONFIG_KCOV=y
 
 CONFIG_KCOV requires gcc built on revision 231296 or later.
+
+If the comparison operands need to be collected, set::
+
+	CONFIG_KCOV_ENABLE_COMPARISONS=y
+
 Profiling data will only become accessible once debugfs has been mounted::
 
         mount -t debugfs none /sys/kernel/debug
 
-The following program demonstrates kcov usage from within a test program:
+Coverage collection
+-------------------
+The following program demonstrates coverage collection from within a test
+program using kcov:
 
 .. code-block:: c
 
@@ -44,6 +55,9 @@ The following program demonstrates kcov usage from within a test program:
     #define KCOV_DISABLE			_IO('c', 101)
     #define COVER_SIZE			(64<<10)
 
+    #define KCOV_TRACE_PC  0
+    #define KCOV_TRACE_CMP 1
+
     int main(int argc, char **argv)
     {
 	int fd;
@@ -64,7 +78,7 @@ The following program demonstrates kcov usage from within a test program:
 	if ((void*)cover == MAP_FAILED)
 		perror("mmap"), exit(1);
 	/* Enable coverage collection on the current thread. */
-	if (ioctl(fd, KCOV_ENABLE, 0))
+	if (ioctl(fd, KCOV_ENABLE, KCOV_TRACE_PC))
 		perror("ioctl"), exit(1);
 	/* Reset coverage from the tail of the ioctl() call. */
 	__atomic_store_n(&cover[0], 0, __ATOMIC_RELAXED);
@@ -111,3 +125,80 @@ The interface is fine-grained to allow efficient forking of test processes.
 That is, a parent process opens /sys/kernel/debug/kcov, enables trace mode,
 mmaps coverage buffer and then forks child processes in a loop. Child processes
 only need to enable coverage (disable happens automatically on thread end).
+
+Comparison operands collection
+------------------------------
+Comparison operands collection is similar to coverage collection:
+
+.. code-block:: c
+
+    /* Same includes and defines as above. */
+
+    /* Number of 64-bit words per record. */
+    #define KCOV_WORDS_PER_CMP 4
+
+    /*
+     * The format for the types of collected comparisons.
+     *
+     * Bit 0 shows whether one of the arguments is a compile-time constant.
+     * Bits 1 & 2 contain log2 of the argument size, up to 8 bytes.
+     */
+
+    #define KCOV_CMP_CONST          (1 << 0)
+    #define KCOV_CMP_SIZE(n)        ((n) << 1)
+    #define KCOV_CMP_MASK           KCOV_CMP_SIZE(3)
+
+    int main(int argc, char **argv)
+    {
+	int fd;
+	uint64_t *cover, type, arg1, arg2, is_const, size;
+	unsigned long n, i;
+
+	fd = open("/sys/kernel/debug/kcov", O_RDWR);
+	if (fd == -1)
+		perror("open"), exit(1);
+	if (ioctl(fd, KCOV_INIT_TRACE, COVER_SIZE))
+		perror("ioctl"), exit(1);
+	/*
+	* Note that the buffer pointer is of type uint64_t*, because all
+	* the comparison operands are promoted to uint64_t.
+	*/
+	cover = (uint64_t *)mmap(NULL, COVER_SIZE * sizeof(unsigned long),
+				     PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if ((void*)cover == MAP_FAILED)
+		perror("mmap"), exit(1);
+	/* Note KCOV_TRACE_CMP instead of KCOV_TRACE_PC. */
+	if (ioctl(fd, KCOV_ENABLE, KCOV_TRACE_CMP))
+		perror("ioctl"), exit(1);
+	__atomic_store_n(&cover[0], 0, __ATOMIC_RELAXED);
+	read(-1, NULL, 0);
+	/* Read number of comparisons collected. */
+	n = __atomic_load_n(&cover[0], __ATOMIC_RELAXED);
+	for (i = 0; i < n; i++) {
+		type = cover[i * KCOV_WORDS_PER_CMP + 1];
+		/* arg1 and arg2 - operands of the comparison. */
+		arg1 = cover[i * KCOV_WORDS_PER_CMP + 2];
+		arg2 = cover[i * KCOV_WORDS_PER_CMP + 3];
+		/* ip - caller address. */
+		ip = cover[i * KCOV_WORDS_PER_CMP + 4];
+		/* size of the operands. */
+		size = 1 << ((type & KCOV_CMP_MASK) >> 1);
+		/* is_const - true if either operand is a compile-time constant.*/
+		is_const = type & KCOV_CMP_CONST;
+		printf("ip: 0x%lx type: 0x%lx, arg1: 0x%lx, arg2: 0x%lx, "
+			"size: %lu, %s\n",
+			ip, type, arg1, arg2, size,
+		is_const ? "const" : "non-const");
+	}
+	if (ioctl(fd, KCOV_DISABLE, 0))
+		perror("ioctl"), exit(1);
+	/* Free resources. */
+	if (munmap(cover, COVER_SIZE * sizeof(unsigned long)))
+		perror("munmap"), exit(1);
+	if (close(fd))
+		perror("close"), exit(1);
+	return 0;
+    }
+
+Note that the kcov modes (coverage collection or comparison operands) are
+mutually exclusive.
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index ec571b9bb18a..2a84bb334894 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -181,6 +181,7 @@ read the file /proc/PID/status:
   VmPTE:        20 kb
   VmSwap:        0 kB
   HugetlbPages:          0 kB
+  CoreDumping:    0
   Threads:        1
   SigQ:   0/28578
   SigPnd: 0000000000000000
@@ -253,6 +254,8 @@ Table 1-2: Contents of the status files (as of 4.8)
  VmSwap                      amount of swap used by anonymous private data
                              (shmem swap usage is not included)
  HugetlbPages                size of hugetlb memory portions
+ CoreDumping                 process's memory is currently being dumped
+                             (killing the process may lead to a corrupted core)
  Threads                     number of threads
  SigQ                        number of signals queued/max. number for queue
  SigPnd                      bitmap of pending signals for the thread
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 055c8b3e1018..b920423f88cb 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -818,7 +818,7 @@ tooling to work, you can do:
 swappiness
 
 This control is used to define how aggressive the kernel will swap
-memory pages.  Higher values will increase agressiveness, lower values
+memory pages.  Higher values will increase aggressiveness, lower values
 decrease the amount of swap.  A value of 0 instructs the kernel not to
 initiate swap until the amount of free and file-backed pages is less
 than the high water mark in a zone.