Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
   ("refactor Kconfig to consolidate KEXEC and CRASH options")

 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h")

 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands")

 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions")

 - Switch the handling of kdump from a udev scheme to in-kernel
   handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
   hot un/plug")

 - Many singleton patches to various parts of the tree

* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
  document while_each_thread(), change first_tid() to use for_each_thread()
  drivers/char/mem.c: shrink character device's devlist[] array
  x86/crash: optimize CPU changes
  crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
  crash: hotplug support for kexec_load()
  x86/crash: add x86 crash hotplug support
  crash: memory and CPU hotplug sysfs attributes
  kexec: exclude elfcorehdr from the segment digest
  crash: add generic infrastructure for crash hotplug support
  crash: move a few code bits to setup support of crash hotplug
  kstrtox: consistently use _tolower()
  kill do_each_thread()
  nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
  scripts/bloat-o-meter: count weak symbol sizes
  treewide: drop CONFIG_EMBEDDED
  lockdep: fix static memory detection even more
  lib/vsprintf: declare no_hash_pointers in sprintf.h
  lib/vsprintf: split out sprintf() and friends
  kernel/fork: stop playing lockless games for exe_file replacement
  adfs: delete unused "union adfs_dirtail" definition
  ...

scripts/checkpatch.pl

@@ -74,6 +74,8 @@ my $git_command ='export LANGUAGE=en_US.UTF-8; git';
 my $tabsize = 8;
 my ${CONFIG_} = "CONFIG_";
 
+my %maybe_linker_symbol; # for externs in c exceptions, when seen in *vmlinux.lds.h
+
 sub help {
 	my ($exitcode) = @_;
 
@@ -3270,7 +3272,7 @@ sub process {
 					# A Fixes:, link or signature tag line
 		      $commit_log_possible_stack_dump)) {
 			WARN("COMMIT_LOG_LONG_LINE",
-			     "Possible unwrapped commit description (prefer a maximum 75 chars per line)\n" . $herecurr);
+			     "Prefer a maximum 75 chars per line (possible unwrapped commit description?)\n" . $herecurr);
 			$commit_log_long_line = 1;
 		}
 
@@ -6051,6 +6053,9 @@ sub process {
 
 # check for line continuations outside of #defines, preprocessor #, and asm
 
+		} elsif ($realfile =~ m@/vmlinux.lds.h$@) {
+		    $line =~ s/(\w+)/$maybe_linker_symbol{$1}++/ge;
+		    #print "REAL: $realfile\nln: $line\nkeys:", sort keys %maybe_linker_symbol;
 		} else {
 			if ($prevline !~ /^..*\\$/ &&
 			    $line !~ /^\+\s*\#.*\\$/ &&		# preprocessor
@@ -7119,6 +7124,21 @@ sub process {
 				     "arguments for function declarations should follow identifier\n" . $herecurr);
 			}
 
+		} elsif ($realfile =~ /\.c$/ && defined $stat &&
+		    $stat =~ /^\+extern struct\s+(\w+)\s+(\w+)\[\];/)
+		{
+			my ($st_type, $st_name) = ($1, $2);
+
+			for my $s (keys %maybe_linker_symbol) {
+			    #print "Linker symbol? $st_name : $s\n";
+			    goto LIKELY_LINKER_SYMBOL
+				if $st_name =~ /$s/;
+			}
+			WARN("AVOID_EXTERNS",
+			     "found a file-scoped extern type:$st_type name:$st_name in .c file\n"
+			     . "is this a linker symbol ?\n" . $herecurr);
+		  LIKELY_LINKER_SYMBOL:
+
 		} elsif ($realfile =~ /\.c$/ && defined $stat &&
 		    $stat =~ /^.\s*extern\s+/)
 		{