diff --git a/fs/coredump.c b/fs/coredump.c
index 320243fde9a4..a2d73242a8c6 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -84,6 +84,8 @@ static int core_uses_pid;
 static unsigned int core_pipe_limit;
 static unsigned int core_sort_vma;
 static char core_pattern[CORENAME_MAX_SIZE] = "core";
+/* Taken around every copy in and out of core_pattern. */
+static DEFINE_SPINLOCK(core_pattern_lock);
 static int core_name_size = CORENAME_MAX_SIZE;
 unsigned int core_file_note_size_limit = CORE_FILE_NOTE_SIZE_DEFAULT;
 static atomic_t core_pipe_count = ATOMIC_INIT(0);
@@ -239,11 +241,16 @@ static bool coredump_parse(struct core_name *cn, struct coredump_params *cprm,
 			   size_t **argv, int *argc)
 {
 	const struct cred *cred = current_cred();
-	const char *pat_ptr = core_pattern;
+	char pattern[CORENAME_MAX_SIZE];
+	const char *pat_ptr = pattern;
 	bool was_space = false;
 	int pid_in_pattern = 0;
 	int err = 0;
 
+	/* The sysctl handler may be publishing a new pattern. */
+	scoped_guard(spinlock, &core_pattern_lock)
+		strscpy(pattern, core_pattern);
+
 	cprm->mask = COREDUMP_KERNEL;
 	if (core_pipe_limit)
 		cprm->mask |= COREDUMP_WAIT;
@@ -1640,11 +1647,11 @@ void validate_coredump_safety(void)
 	}
 }
 
-static inline bool check_coredump_socket(void)
+static inline bool check_coredump_socket(const char *pattern)
 {
 	const char *p;
 
-	if (core_pattern[0] != '@')
+	if (pattern[0] != '@')
 		return true;
 
 	/*
@@ -1656,16 +1663,16 @@ static inline bool check_coredump_socket(void)
 		return false;
 
 	/* Must be an absolute path... */
-	if (core_pattern[1] != '/') {
+	if (pattern[1] != '/') {
 		/* ... or the socket request protocol... */
-		if (core_pattern[1] != '@')
+		if (pattern[1] != '@')
 			return false;
 		/* ... and if so must be an absolute path. */
-		if (core_pattern[2] != '/')
+		if (pattern[2] != '/')
 			return false;
-		p = &core_pattern[2];
+		p = &pattern[2];
 	} else {
-		p = &core_pattern[1];
+		p = &pattern[1];
 	}
 
 	/* The path obviously cannot exceed UNIX_PATH_MAX. */
@@ -1673,7 +1680,7 @@ static inline bool check_coredump_socket(void)
 		return false;
 
 	/* Must not contain ".." in the path. */
-	if (name_contains_dotdot(core_pattern))
+	if (name_contains_dotdot(pattern))
 		return false;
 
 	return true;
@@ -1682,27 +1689,35 @@ static inline bool check_coredump_socket(void)
 static int proc_dostring_coredump(const struct ctl_table *table, int write,
 		  void *buffer, size_t *lenp, loff_t *ppos)
 {
+	char pattern[CORENAME_MAX_SIZE];
+	const struct ctl_table tmp = {
+		.procname	= table->procname,
+		.data		= pattern,
+		.maxlen		= sizeof(pattern),
+	};
+	bool changed = false;
 	int error;
-	ssize_t retval;
-	char old_core_pattern[CORENAME_MAX_SIZE];
 
-	if (!write)
-		return proc_dostring(table, write, buffer, lenp, ppos);
+	/* Work on a copy, proc_dostring() appends at *ppos. */
+	scoped_guard(spinlock, &core_pattern_lock)
+		strscpy(pattern, core_pattern);
 
-	retval = strscpy(old_core_pattern, core_pattern, CORENAME_MAX_SIZE);
-
-	error = proc_dostring(table, write, buffer, lenp, ppos);
-	if (error)
+	error = proc_dostring(&tmp, write, buffer, lenp, ppos);
+	if (error || !write)
 		return error;
 
-	if (!check_coredump_socket()) {
-		strscpy(core_pattern, old_core_pattern, retval + 1);
+	if (!check_coredump_socket(pattern))
 		return -EINVAL;
-	}
 
-	if (strncmp(old_core_pattern, core_pattern, CORENAME_MAX_SIZE))
+	/* Publish the validated pattern whole. */
+	scoped_guard(spinlock, &core_pattern_lock) {
+		changed = strncmp(pattern, core_pattern, CORENAME_MAX_SIZE);
+		if (changed)
+			strscpy(core_pattern, pattern);
+	}
+	if (changed)
 		validate_coredump_safety();
-	return error;
+	return 0;
 }
 
 static const unsigned int core_file_note_size_min = CORE_FILE_NOTE_SIZE_DEFAULT;