Merge tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:
 "Significant patch series in this pull request:

   - "squashfs: Remove page->mapping references" (Matthew Wilcox) gets
     us closer to being able to remove page->mapping

   - "relayfs: misc changes" (Jason Xing) does some maintenance and
     minor feature addition work in relayfs

   - "kdump: crashkernel reservation from CMA" (Jiri Bohac) switches
     us from static preallocation of the kdump crashkernel's working
     memory over to dynamic allocation. So the difficulty of a-priori
     estimation of the second kernel's needs is removed and the first
     kernel obtains extra memory

   - "generalize panic_print's dump function to be used by other
     kernel parts" (Feng Tang) implements some consolidation and
     rationalization of the various ways in which a failing kernel
     splats information at the operator

* tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (80 commits)
  tools/getdelays: add backward compatibility for taskstats version
  kho: add test for kexec handover
  delaytop: enhance error logging and add PSI feature description
  samples: Kconfig: fix spelling mistake "instancess" -> "instances"
  fat: fix too many log in fat_chain_add()
  scripts/spelling.txt: add notifer||notifier to spelling.txt
  xen/xenbus: fix typo "notifer"
  net: mvneta: fix typo "notifer"
  drm/xe: fix typo "notifer"
  cxl: mce: fix typo "notifer"
  KVM: x86: fix typo "notifer"
  MAINTAINERS: add maintainers for delaytop
  ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below()
  ucount: fix atomic_long_inc_below() argument type
  kexec: enable CMA based contiguous allocation
  stackdepot: make max number of pools boot-time configurable
  lib/xxhash: remove unused functions
  init/Kconfig: restore CONFIG_BROKEN help text
  lib/raid6: update recov_rvv.c zero page usage
  docs: update docs after introducing delaytop
  ...

1 files changed, 122 insertions, 0 deletions

diff --git a/lib/sys_info.c b/lib/sys_info.c
new file mode 100644
index 000000000000..5bf503fd7ec1
--- /dev/null
+++ b/lib/sys_info.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/sched/debug.h>
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/sysctl.h>
+#include <linux/nmi.h>
+
+#include <linux/sys_info.h>
+
+struct sys_info_name {
+	unsigned long bit;
+	const char *name;
+};
+
+/*
+ * When 'si_names' gets updated,  please make sure the 'sys_info_avail'
+ * below is updated accordingly.
+ */
+static const struct sys_info_name  si_names[] = {
+	{ SYS_INFO_TASKS,		"tasks" },
+	{ SYS_INFO_MEM,			"mem" },
+	{ SYS_INFO_TIMERS,		"timers" },
+	{ SYS_INFO_LOCKS,		"locks" },
+	{ SYS_INFO_FTRACE,		"ftrace" },
+	{ SYS_INFO_ALL_CPU_BT,		"all_bt" },
+	{ SYS_INFO_BLOCKED_TASKS,	"blocked_tasks" },
+};
+
+/* Expecting string like "xxx_sys_info=tasks,mem,timers,locks,ftrace,..." */
+unsigned long sys_info_parse_param(char *str)
+{
+	unsigned long si_bits = 0;
+	char *s, *name;
+	int i;
+
+	s = str;
+	while ((name = strsep(&s, ",")) && *name) {
+		for (i = 0; i < ARRAY_SIZE(si_names); i++) {
+			if (!strcmp(name, si_names[i].name)) {
+				si_bits |= si_names[i].bit;
+				break;
+			}
+		}
+	}
+
+	return si_bits;
+}
+
+#ifdef CONFIG_SYSCTL
+
+static const char sys_info_avail[] __maybe_unused = "tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks";
+
+int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write,
+					  void *buffer, size_t *lenp,
+					  loff_t *ppos)
+{
+	char names[sizeof(sys_info_avail) + 1];
+	struct ctl_table table;
+	unsigned long *si_bits_global;
+
+	si_bits_global = ro_table->data;
+
+	if (write) {
+		unsigned long si_bits;
+		int ret;
+
+		table = *ro_table;
+		table.data = names;
+		table.maxlen = sizeof(names);
+		ret = proc_dostring(&table, write, buffer, lenp, ppos);
+		if (ret)
+			return ret;
+
+		si_bits = sys_info_parse_param(names);
+		/* The access to the global value is not synchronized. */
+		WRITE_ONCE(*si_bits_global, si_bits);
+		return 0;
+	} else {
+		/* for 'read' operation */
+		char *delim = "";
+		int i, len = 0;
+
+		for (i = 0; i < ARRAY_SIZE(si_names); i++) {
+			if (*si_bits_global & si_names[i].bit) {
+				len += scnprintf(names + len, sizeof(names) - len,
+					"%s%s", delim, si_names[i].name);
+				delim = ",";
+			}
+		}
+
+		table = *ro_table;
+		table.data = names;
+		table.maxlen = sizeof(names);
+		return proc_dostring(&table, write, buffer, lenp, ppos);
+	}
+}
+#endif
+
+void sys_info(unsigned long si_mask)
+{
+	if (si_mask & SYS_INFO_TASKS)
+		show_state();
+
+	if (si_mask & SYS_INFO_MEM)
+		show_mem();
+
+	if (si_mask & SYS_INFO_TIMERS)
+		sysrq_timer_list_show();
+
+	if (si_mask & SYS_INFO_LOCKS)
+		debug_show_all_locks();
+
+	if (si_mask & SYS_INFO_FTRACE)
+		ftrace_dump(DUMP_ALL);
+
+	if (si_mask & SYS_INFO_ALL_CPU_BT)
+		trigger_all_cpu_backtrace();
+
+	if (si_mask & SYS_INFO_BLOCKED_TASKS)
+		show_state_filter(TASK_UNINTERRUPTIBLE);
+}