Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "Various misc subsystems, before getting into the post-linux-next
  material.

  41 patches.

  Subsystems affected by this patch series: procfs, misc, core-kernel,
  lib, checkpatch, init, pipe, minix, fat, cgroups, kexec, kdump,
  taskstats, panic, kcov, resource, and ubsan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits)
  Revert "ubsan, kcsan: Don't combine sanitizer with kcov on clang"
  kernel/resource: fix kfree() of bootmem memory again
  kcov: properly handle subsequent mmap calls
  kcov: split ioctl handling into locked and unlocked parts
  panic: move panic_print before kmsg dumpers
  panic: add option to dump all CPUs backtraces in panic_print
  docs: sysctl/kernel: add missing bit to panic_print
  taskstats: remove unneeded dead assignment
  kasan: no need to unset panic_on_warn in end_report()
  ubsan: no need to unset panic_on_warn in ubsan_epilogue()
  panic: unset panic_on_warn inside panic()
  docs: kdump: add scp example to write out the dump file
  docs: kdump: update description about sysfs file system support
  arm64: mm: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  x86/setup: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  riscv: mm: init: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  kexec: make crashk_res, crashk_low_res and crash_notes symbols always visible
  cgroup: use irqsave in cgroup_rstat_flush_locked().
  fat: use pointer to simple type in put_user()
  minix: fix bug when opening a file with O_DIRECT
  ...

5 files changed, 94 insertions, 105 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1063ce0abd97..cfe3b092c31d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -208,20 +208,87 @@ config DEBUG_BUGVERBOSE
 
 endmenu # "printk and dmesg options"
 
+config DEBUG_KERNEL
+	bool "Kernel debugging"
+	help
+	  Say Y here if you are developing drivers or trying to debug and
+	  identify kernel problems.
+
+config DEBUG_MISC
+	bool "Miscellaneous debug code"
+	default DEBUG_KERNEL
+	depends on DEBUG_KERNEL
+	help
+	  Say Y here if you need to enable miscellaneous debug code that should
+	  be under a more specific debug option but isn't.
+
 menu "Compile-time checks and compiler options"
 
 config DEBUG_INFO
-	bool "Compile the kernel with debug info"
-	depends on DEBUG_KERNEL && !COMPILE_TEST
+	bool
 	help
-	  If you say Y here the resulting kernel image will include
-	  debugging info resulting in a larger kernel image.
+	  A kernel debug info option other than "None" has been selected
+	  in the "Debug information" choice below, indicating that debug
+	  information will be generated for build targets.
+
+choice
+	prompt "Debug information"
+	depends on DEBUG_KERNEL
+	help
+	  Selecting something other than "None" results in a kernel image
+	  that will include debugging info resulting in a larger kernel image.
 	  This adds debug symbols to the kernel and modules (gcc -g), and
 	  is needed if you intend to use kernel crashdump or binary object
 	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
-	  Say Y here only if you plan to debug the kernel.
 
-	  If unsure, say N.
+	  Choose which version of DWARF debug info to emit. If unsure,
+	  select "Toolchain default".
+
+config DEBUG_INFO_NONE
+	bool "Disable debug information"
+	help
+	  Do not build the kernel with debugging information, which will
+	  result in a faster and smaller build.
+
+config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
+	bool "Rely on the toolchain's implicit default DWARF version"
+	select DEBUG_INFO
+	help
+	  The implicit default version of DWARF debug info produced by a
+	  toolchain changes over time.
+
+	  This can break consumers of the debug info that haven't upgraded to
+	  support newer revisions, and prevent testing newer versions, but
+	  those should be less common scenarios.
+
+config DEBUG_INFO_DWARF4
+	bool "Generate DWARF Version 4 debuginfo"
+	select DEBUG_INFO
+	help
+	  Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
+
+	  If you have consumers of DWARF debug info that are not ready for
+	  newer revisions of DWARF, you may wish to choose this or have your
+	  config select this.
+
+config DEBUG_INFO_DWARF5
+	bool "Generate DWARF Version 5 debuginfo"
+	select DEBUG_INFO
+	depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
+	help
+	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
+	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
+	  draft features until 7.0), and gdb 8.0+.
+
+	  Changes to the structure of debug info in Version 5 allow for around
+	  15-18% savings in resulting image and debug info section sizes as
+	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
+	  extensions such as accelerators for symbol indexing and the format
+	  for fission (.dwo/.dwp) files. Users may not want to select this
+	  config if they rely on tooling that has not yet been updated to
+	  support DWARF Version 5.
+
+endchoice # "Debug information"
 
 if DEBUG_INFO
 
@@ -267,56 +334,12 @@ config DEBUG_INFO_SPLIT
 	  to know about the .dwo files and include them.
 	  Incompatible with older versions of ccache.
 
-choice
-	prompt "DWARF version"
-	help
-	  Which version of DWARF debug info to emit.
-
-config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
-	bool "Rely on the toolchain's implicit default DWARF version"
-	help
-	  The implicit default version of DWARF debug info produced by a
-	  toolchain changes over time.
-
-	  This can break consumers of the debug info that haven't upgraded to
-	  support newer revisions, and prevent testing newer versions, but
-	  those should be less common scenarios.
-
-	  If unsure, say Y.
-
-config DEBUG_INFO_DWARF4
-	bool "Generate DWARF Version 4 debuginfo"
-	help
-	  Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
-
-	  If you have consumers of DWARF debug info that are not ready for
-	  newer revisions of DWARF, you may wish to choose this or have your
-	  config select this.
-
-config DEBUG_INFO_DWARF5
-	bool "Generate DWARF Version 5 debuginfo"
-	depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
-	depends on !DEBUG_INFO_BTF || PAHOLE_VERSION >= 121
-	help
-	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
-	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
-	  draft features until 7.0), and gdb 8.0+.
-
-	  Changes to the structure of debug info in Version 5 allow for around
-	  15-18% savings in resulting image and debug info section sizes as
-	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
-	  extensions such as accelerators for symbol indexing and the format
-	  for fission (.dwo/.dwp) files. Users may not want to select this
-	  config if they rely on tooling that has not yet been updated to
-	  support DWARF Version 5.
-
-endchoice # "DWARF version"
-
 config DEBUG_INFO_BTF
 	bool "Generate BTF typeinfo"
 	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
 	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
 	depends on BPF_SYSCALL
+	depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
 	help
 	  Generate deduplicated BTF type information from DWARF debug info.
 	  Turning this on expects presence of pahole tool, which will convert
@@ -434,7 +457,8 @@ config SECTION_MISMATCH_WARN_ONLY
 	  If unsure, say Y.
 
 config DEBUG_FORCE_FUNCTION_ALIGN_64B
-	bool "Force all function address 64B aligned" if EXPERT
+	bool "Force all function address 64B aligned"
+	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
 	help
 	  There are cases that a commit from one domain changes the function
 	  address alignment of other domains, and cause magic performance
@@ -603,20 +627,6 @@ source "lib/Kconfig.kcsan"
 
 endmenu
 
-config DEBUG_KERNEL
-	bool "Kernel debugging"
-	help
-	  Say Y here if you are developing drivers or trying to debug and
-	  identify kernel problems.
-
-config DEBUG_MISC
-	bool "Miscellaneous debug code"
-	default DEBUG_KERNEL
-	depends on DEBUG_KERNEL
-	help
-	  Say Y here if you need to enable miscellaneous debug code that should
-	  be under a more specific debug option but isn't.
-
 menu "Networking Debugging"
 
 source "net/Kconfig.debug"
diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index 63b70b8c5551..de022445fbba 100644
--- a/lib/Kconfig.kcsan
+++ b/lib/Kconfig.kcsan
@@ -10,21 +10,10 @@ config HAVE_KCSAN_COMPILER
 	  For the list of compilers that support KCSAN, please see
 	  <file:Documentation/dev-tools/kcsan.rst>.
 
-config KCSAN_KCOV_BROKEN
-	def_bool KCOV && CC_HAS_SANCOV_TRACE_PC
-	depends on CC_IS_CLANG
-	depends on !$(cc-option,-Werror=unused-command-line-argument -fsanitize=thread -fsanitize-coverage=trace-pc)
-	help
-	  Some versions of clang support either KCSAN and KCOV but not the
-	  combination of the two.
-	  See https://bugs.llvm.org/show_bug.cgi?id=45831 for the status
-	  in newer releases.
-
 menuconfig KCSAN
 	bool "KCSAN: dynamic data race detector"
 	depends on HAVE_ARCH_KCSAN && HAVE_KCSAN_COMPILER
 	depends on DEBUG_KERNEL && !KASAN
-	depends on !KCSAN_KCOV_BROKEN
 	select STACKTRACE
 	help
 	  The Kernel Concurrency Sanitizer (KCSAN) is a dynamic
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 236c5cefc4cc..f3c57ed51838 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -27,16 +27,6 @@ config UBSAN_TRAP
 	  the system. For some system builders this is an acceptable
 	  trade-off.
 
-config UBSAN_KCOV_BROKEN
-	def_bool KCOV && CC_HAS_SANCOV_TRACE_PC
-	depends on CC_IS_CLANG
-	depends on !$(cc-option,-Werror=unused-command-line-argument -fsanitize=bounds -fsanitize-coverage=trace-pc)
-	help
-	  Some versions of clang support either UBSAN or KCOV but not the
-	  combination of the two.
-	  See https://bugs.llvm.org/show_bug.cgi?id=45831 for the status
-	  in newer releases.
-
 config CC_HAS_UBSAN_BOUNDS
 	def_bool $(cc-option,-fsanitize=bounds)
 
@@ -46,7 +36,6 @@ config CC_HAS_UBSAN_ARRAY_BOUNDS
 config UBSAN_BOUNDS
 	bool "Perform array index bounds checking"
 	default UBSAN
-	depends on !UBSAN_KCOV_BROKEN
 	depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS
 	help
 	  This option enables detection of directly indexed out of bounds
@@ -72,7 +61,6 @@ config UBSAN_ARRAY_BOUNDS
 config UBSAN_LOCAL_BOUNDS
 	bool "Perform array local bounds checking"
 	depends on UBSAN_TRAP
-	depends on !UBSAN_KCOV_BROKEN
 	depends on $(cc-option,-fsanitize=local-bounds)
 	help
 	  This option enables -fsanitize=local-bounds which traps when an
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 926408883456..0d5c2ece0bcb 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -492,6 +492,11 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
  * @list: indicates whether the bitmap must be list
  *      true:  print in decimal list format
  *      false: print in hexadecimal bitmask format
+ * @buf: buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ * @off: in the string from which we are copying, We copy to @buf
+ * @count: the maximum number of bytes to print
  */
 static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
 		int nmaskbits, loff_t off, size_t count)
@@ -512,6 +517,11 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
 
 /**
  * bitmap_print_bitmask_to_buf  - convert bitmap to hex bitmask format ASCII string
+ * @buf: buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ * @off: in the string from which we are copying, We copy to @buf
+ * @count: the maximum number of bytes to print
  *
  * The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
  * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
@@ -553,12 +563,6 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
  * move to use bin_attribute. In result, we have to pass the corresponding
  * parameters such as off, count from bin_attribute show entry to this API.
  *
- * @buf: buffer into which string is placed
- * @maskp: pointer to bitmap to convert
- * @nmaskbits: size of bitmap, in bits
- * @off: in the string from which we are copying, We copy to @buf
- * @count: the maximum number of bytes to print
- *
  * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
  * is similar with cpumap_print_to_pagebuf(),  the difference is that
  * bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
@@ -597,6 +601,11 @@ EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
 
 /**
  * bitmap_print_list_to_buf  - convert bitmap to decimal list format ASCII string
+ * @buf: buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ * @off: in the string from which we are copying, We copy to @buf
+ * @count: the maximum number of bytes to print
  *
  * Everything is same with the above bitmap_print_bitmask_to_buf() except
  * the print format.
@@ -807,7 +816,8 @@ EXPORT_SYMBOL(bitmap_parselist);
 
 
 /**
- * bitmap_parselist_user()
+ * bitmap_parselist_user() - convert user buffer's list format ASCII
+ * string to bitmap
  *
  * @ubuf: pointer to user buffer containing string.
  * @ulen: buffer size in bytes.  If string is smaller than this
diff --git a/lib/ubsan.c b/lib/ubsan.c
index bdc380ff5d5c..36bd75e33426 100644
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -154,16 +154,8 @@ static void ubsan_epilogue(void)
 
 	current->in_ubsan--;
 
-	if (panic_on_warn) {
-		/*
-		 * This thread may hit another WARN() in the panic path.
-		 * Resetting this prevents additional WARN() from panicking the
-		 * system on this thread.  Other threads are blocked by the
-		 * panic_mutex in panic().
-		 */
-		panic_on_warn = 0;
+	if (panic_on_warn)
 		panic("panic_on_warn set ...\n");
-	}
 }
 
 void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)