Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 288 insertions, 0 deletions

diff --git a/security/commoncap_test.c b/security/commoncap_test.c
new file mode 100644
index 000000000..e9b278be3
--- /dev/null
+++ b/security/commoncap_test.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * KUnit tests for commoncap.c security functions
+ *
+ * Tests for security-critical functions in the capability subsystem,
+ * particularly namespace-related capability checks.
+ */
+
+#include <kunit/test.h>
+#include <linux/user_namespace.h>
+#include <linux/uidgid.h>
+#include <linux/cred.h>
+#include <linux/mnt_idmapping.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/refcount.h>
+
+#ifdef CONFIG_SECURITY_COMMONCAP_KUNIT_TEST
+
+/* Functions are static in commoncap.c, but we can call them since we're
+ * included in the same compilation unit when tests are enabled.
+ */
+
+/**
+ * test_vfsuid_root_in_currentns_init_ns - Test vfsuid_root_in_currentns with init ns
+ *
+ * Verifies that UID 0 in the init namespace correctly owns the current
+ * namespace when running in init_user_ns.
+ *
+ * @test: KUnit test context
+ */
+static void test_vfsuid_root_in_currentns_init_ns(struct kunit *test)
+{
+	vfsuid_t vfsuid;
+	kuid_t kuid;
+
+	/* Create UID 0 in init namespace */
+	kuid = KUIDT_INIT(0);
+	vfsuid = VFSUIDT_INIT(kuid);
+
+	/* In init namespace, UID 0 should own current namespace */
+	KUNIT_EXPECT_TRUE(test, vfsuid_root_in_currentns(vfsuid));
+}
+
+/**
+ * test_vfsuid_root_in_currentns_invalid - Test vfsuid_root_in_currentns with invalid vfsuid
+ *
+ * Verifies that an invalid vfsuid correctly returns false.
+ *
+ * @test: KUnit test context
+ */
+static void test_vfsuid_root_in_currentns_invalid(struct kunit *test)
+{
+	vfsuid_t invalid_vfsuid;
+
+	/* Use the predefined invalid vfsuid */
+	invalid_vfsuid = INVALID_VFSUID;
+
+	/* Invalid vfsuid should return false */
+	KUNIT_EXPECT_FALSE(test, vfsuid_root_in_currentns(invalid_vfsuid));
+}
+
+/**
+ * test_vfsuid_root_in_currentns_nonzero - Test vfsuid_root_in_currentns with non-zero UID
+ *
+ * Verifies that a non-zero UID correctly returns false.
+ *
+ * @test: KUnit test context
+ */
+static void test_vfsuid_root_in_currentns_nonzero(struct kunit *test)
+{
+	vfsuid_t vfsuid;
+	kuid_t kuid;
+
+	/* Create a non-zero UID */
+	kuid = KUIDT_INIT(1000);
+	vfsuid = VFSUIDT_INIT(kuid);
+
+	/* Non-zero UID should return false */
+	KUNIT_EXPECT_FALSE(test, vfsuid_root_in_currentns(vfsuid));
+}
+
+/**
+ * test_kuid_root_in_ns_init_ns_uid0 - Test kuid_root_in_ns with init namespace and UID 0
+ *
+ * Verifies that kuid_root_in_ns correctly identifies UID 0 in init namespace.
+ * This tests the core namespace traversal logic. In init namespace, UID 0
+ * maps to itself, so it should own the namespace.
+ *
+ * @test: KUnit test context
+ */
+static void test_kuid_root_in_ns_init_ns_uid0(struct kunit *test)
+{
+	kuid_t kuid;
+	struct user_namespace *init_ns;
+
+	kuid = KUIDT_INIT(0);
+	init_ns = &init_user_ns;
+
+	/* UID 0 should own init namespace */
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(kuid, init_ns));
+}
+
+/**
+ * test_kuid_root_in_ns_init_ns_nonzero - Test kuid_root_in_ns with init namespace and non-zero UID
+ *
+ * Verifies that kuid_root_in_ns correctly rejects non-zero UIDs in init namespace.
+ * Only UID 0 should own a namespace.
+ *
+ * @test: KUnit test context
+ */
+static void test_kuid_root_in_ns_init_ns_nonzero(struct kunit *test)
+{
+	kuid_t kuid;
+	struct user_namespace *init_ns;
+
+	kuid = KUIDT_INIT(1000);
+	init_ns = &init_user_ns;
+
+	/* Non-zero UID should not own namespace */
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(kuid, init_ns));
+}
+
+/**
+ * create_test_user_ns_with_mapping - Create a mock user namespace with UID mapping
+ *
+ * Creates a minimal user namespace structure for testing where uid 0 in the
+ * namespace maps to a specific kuid in the parent namespace.
+ *
+ * @test: KUnit test context
+ * @parent_ns: Parent namespace (typically init_user_ns)
+ * @mapped_kuid: The kuid that uid 0 in this namespace maps to in parent
+ *
+ * Returns: Pointer to allocated namespace, or NULL on failure
+ */
+static struct user_namespace *create_test_user_ns_with_mapping(struct kunit *test,
+								 struct user_namespace *parent_ns,
+								 kuid_t mapped_kuid)
+{
+	struct user_namespace *ns;
+	struct uid_gid_extent extent;
+
+	/* Allocate a test namespace - use kzalloc to zero all fields */
+	ns = kunit_kzalloc(test, sizeof(*ns), GFP_KERNEL);
+	if (!ns)
+		return NULL;
+
+	/* Initialize basic namespace structure fields */
+	ns->parent = parent_ns;
+	ns->level = parent_ns ? parent_ns->level + 1 : 0;
+	ns->owner = mapped_kuid;
+	ns->group = KGIDT_INIT(0);
+
+	/* Initialize ns_common structure */
+	refcount_set(&ns->ns.__ns_ref, 1);
+	ns->ns.inum = 0; /* Mock inum */
+
+	/* Set up uid mapping: uid 0 in this namespace maps to mapped_kuid in parent
+	 * Format: first (uid in ns) : lower_first (kuid in parent) : count
+	 * So: uid 0 in ns -> kuid mapped_kuid in parent
+	 * This means from_kuid(ns, mapped_kuid) returns 0
+	 */
+	extent.first = 0;                              /* uid 0 in this namespace */
+	extent.lower_first = __kuid_val(mapped_kuid);  /* maps to this kuid in parent */
+	extent.count = 1;
+
+	ns->uid_map.extent[0] = extent;
+	ns->uid_map.nr_extents = 1;
+
+	/* Set up gid mapping: gid 0 maps to gid 0 in parent (simplified) */
+	extent.first = 0;
+	extent.lower_first = 0;
+	extent.count = 1;
+
+	ns->gid_map.extent[0] = extent;
+	ns->gid_map.nr_extents = 1;
+
+	return ns;
+}
+
+/**
+ * test_kuid_root_in_ns_with_mapping - Test kuid_root_in_ns with namespace where uid 0
+ *				       maps to different kuid
+ *
+ * Creates a user namespace where uid 0 maps to kuid 1000 in the parent namespace.
+ * Verifies that kuid_root_in_ns correctly identifies kuid 1000 as owning the namespace.
+ *
+ * Note: kuid_root_in_ns walks up the namespace hierarchy, so it checks the current
+ * namespace first, then parent, then parent's parent, etc. So:
+ * - kuid 1000 owns test_ns because from_kuid(test_ns, 1000) == 0
+ * - kuid 0 also owns test_ns because from_kuid(init_user_ns, 0) == 0
+ *   (checked in parent)
+ *
+ * This tests the actual functionality as requested: creating namespaces with
+ * different values for the namespace's uid 0.
+ *
+ * @test: KUnit test context
+ */
+static void test_kuid_root_in_ns_with_mapping(struct kunit *test)
+{
+	struct user_namespace *test_ns;
+	struct user_namespace *parent_ns;
+	kuid_t mapped_kuid, other_kuid;
+
+	parent_ns = &init_user_ns;
+	mapped_kuid = KUIDT_INIT(1000);
+	other_kuid = KUIDT_INIT(2000);
+
+	test_ns = create_test_user_ns_with_mapping(test, parent_ns, mapped_kuid);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, test_ns);
+
+	/* kuid 1000 should own test_ns because it maps to uid 0 in test_ns */
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(mapped_kuid, test_ns));
+
+	/* kuid 0 should also own test_ns (checked via parent init_user_ns) */
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), test_ns));
+
+	/* Other kuids should not own test_ns */
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(other_kuid, test_ns));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(500), test_ns));
+}
+
+/**
+ * test_kuid_root_in_ns_with_different_mappings - Test with multiple namespaces
+ *
+ * Creates multiple user namespaces with different UID mappings to verify
+ * that kuid_root_in_ns correctly distinguishes between namespaces.
+ *
+ * Each namespace maps uid 0 to a different kuid, and we verify that each
+ * kuid only owns its corresponding namespace (plus kuid 0 owns all via
+ * init_user_ns parent).
+ *
+ * @test: KUnit test context
+ */
+static void test_kuid_root_in_ns_with_different_mappings(struct kunit *test)
+{
+	struct user_namespace *ns1, *ns2, *ns3;
+
+	/* Create three independent namespaces, each mapping uid 0 to different kuids */
+	ns1 = create_test_user_ns_with_mapping(test, &init_user_ns, KUIDT_INIT(1000));
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ns1);
+
+	ns2 = create_test_user_ns_with_mapping(test, &init_user_ns, KUIDT_INIT(2000));
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ns2);
+
+	ns3 = create_test_user_ns_with_mapping(test, &init_user_ns, KUIDT_INIT(3000));
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ns3);
+
+	/* Test ns1: kuid 1000 owns it, kuid 0 owns it (via parent), others do not */
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(1000), ns1));
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), ns1));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(2000), ns1));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(3000), ns1));
+
+	/* Test ns2: kuid 2000 owns it, kuid 0 owns it (via parent), others do not */
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(2000), ns2));
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), ns2));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(1000), ns2));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(3000), ns2));
+
+	/* Test ns3: kuid 3000 owns it, kuid 0 owns it (via parent), others do not */
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(3000), ns3));
+	KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), ns3));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(1000), ns3));
+	KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(2000), ns3));
+}
+
+static struct kunit_case commoncap_test_cases[] = {
+	KUNIT_CASE(test_vfsuid_root_in_currentns_init_ns),
+	KUNIT_CASE(test_vfsuid_root_in_currentns_invalid),
+	KUNIT_CASE(test_vfsuid_root_in_currentns_nonzero),
+	KUNIT_CASE(test_kuid_root_in_ns_init_ns_uid0),
+	KUNIT_CASE(test_kuid_root_in_ns_init_ns_nonzero),
+	KUNIT_CASE(test_kuid_root_in_ns_with_mapping),
+	KUNIT_CASE(test_kuid_root_in_ns_with_different_mappings),
+	{}
+};
+
+static struct kunit_suite commoncap_test_suite = {
+	.name = "commoncap",
+	.test_cases = commoncap_test_cases,
+};
+
+kunit_test_suite(commoncap_test_suite);
+
+MODULE_LICENSE("GPL");
+
+#endif /* CONFIG_SECURITY_COMMONCAP_KUNIT_TEST */