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authorBeau Belgrave <beaub@linux.microsoft.com>2023-04-26 01:51:06 +0300
committerSteven Rostedt (Google) <rostedt@goodmis.org>2023-04-26 04:04:32 +0300
commit97bbce89bfdec9219dfcb60cd62b815a97cb29cb (patch)
tree9357a328f42b9c1c085e1afd8ec631fda88c276d /tools/testing/selftests/user_events
parent17b439db21d5dbe70c419e982262621e5e6aba7f (diff)
downloadlinux-97bbce89bfdec9219dfcb60cd62b815a97cb29cb.tar.xz
tracing/user_events: Prevent same address and bit per process
User processes register an address and bit pair for events. If the same address and bit pair are registered multiple times in the same process, it can cause undefined behavior when events are enabled/disabled. When more than one are used, the bit could be turned off by another event being disabled, while the original event is still enabled. Prevent undefined behavior by checking the current mm to see if any event has already been registered for the address and bit pair. Return EADDRINUSE back to the user process if it's already being used. Update ftrace self-test to ensure this occurs properly. Link: https://lkml.kernel.org/r/20230425225107.8525-4-beaub@linux.microsoft.com Suggested-by: Doug Cook <dcook@linux.microsoft.com> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'tools/testing/selftests/user_events')
-rw-r--r--tools/testing/selftests/user_events/ftrace_test.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
index 91272f9d6fce..7c99cef94a65 100644
--- a/tools/testing/selftests/user_events/ftrace_test.c
+++ b/tools/testing/selftests/user_events/ftrace_test.c
@@ -219,7 +219,12 @@ TEST_F(user, register_events) {
ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
ASSERT_EQ(0, reg.write_index);
- /* Multiple registers should result in same index */
+ /* Multiple registers to the same addr + bit should fail */
+ ASSERT_EQ(-1, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(EADDRINUSE, errno);
+
+ /* Multiple registers to same name should result in same index */
+ reg.enable_bit = 30;
ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
ASSERT_EQ(0, reg.write_index);
@@ -242,6 +247,8 @@ TEST_F(user, register_events) {
/* Unregister */
ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSUNREG, &unreg));
+ unreg.disable_bit = 30;
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSUNREG, &unreg));
/* Delete should work only after close and unregister */
close(self->data_fd);