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-rw-r--r--Documentation/dev-tools/kasan.rst41
1 files changed, 31 insertions, 10 deletions
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index 858c77fe7d..d7de44f533 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -169,7 +169,7 @@ Error reports
A typical KASAN report looks like this::
==================================================================
- BUG: KASAN: slab-out-of-bounds in kmalloc_oob_right+0xa8/0xbc [test_kasan]
+ BUG: KASAN: slab-out-of-bounds in kmalloc_oob_right+0xa8/0xbc [kasan_test]
Write of size 1 at addr ffff8801f44ec37b by task insmod/2760
CPU: 1 PID: 2760 Comm: insmod Not tainted 4.19.0-rc3+ #698
@@ -179,8 +179,8 @@ A typical KASAN report looks like this::
print_address_description+0x73/0x280
kasan_report+0x144/0x187
__asan_report_store1_noabort+0x17/0x20
- kmalloc_oob_right+0xa8/0xbc [test_kasan]
- kmalloc_tests_init+0x16/0x700 [test_kasan]
+ kmalloc_oob_right+0xa8/0xbc [kasan_test]
+ kmalloc_tests_init+0x16/0x700 [kasan_test]
do_one_initcall+0xa5/0x3ae
do_init_module+0x1b6/0x547
load_module+0x75df/0x8070
@@ -200,8 +200,8 @@ A typical KASAN report looks like this::
save_stack+0x43/0xd0
kasan_kmalloc+0xa7/0xd0
kmem_cache_alloc_trace+0xe1/0x1b0
- kmalloc_oob_right+0x56/0xbc [test_kasan]
- kmalloc_tests_init+0x16/0x700 [test_kasan]
+ kmalloc_oob_right+0x56/0xbc [kasan_test]
+ kmalloc_tests_init+0x16/0x700 [kasan_test]
do_one_initcall+0xa5/0x3ae
do_init_module+0x1b6/0x547
load_module+0x75df/0x8070
@@ -277,6 +277,27 @@ traces point to places in code that interacted with the object but that are not
directly present in the bad access stack trace. Currently, this includes
call_rcu() and workqueue queuing.
+CONFIG_KASAN_EXTRA_INFO
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Enabling CONFIG_KASAN_EXTRA_INFO allows KASAN to record and report more
+information. The extra information currently supported is the CPU number and
+timestamp at allocation and free. More information can help find the cause of
+the bug and correlate the error with other system events, at the cost of using
+extra memory to record more information (more cost details in the help text of
+CONFIG_KASAN_EXTRA_INFO).
+
+Here is the report with CONFIG_KASAN_EXTRA_INFO enabled (only the
+different parts are shown)::
+
+ ==================================================================
+ ...
+ Allocated by task 134 on cpu 5 at 229.133855s:
+ ...
+ Freed by task 136 on cpu 3 at 230.199335s:
+ ...
+ ==================================================================
+
Implementation details
----------------------
@@ -510,15 +531,15 @@ When a test passes::
When a test fails due to a failed ``kmalloc``::
- # kmalloc_large_oob_right: ASSERTION FAILED at lib/test_kasan.c:163
+ # kmalloc_large_oob_right: ASSERTION FAILED at mm/kasan/kasan_test.c:245
Expected ptr is not null, but is
- not ok 4 - kmalloc_large_oob_right
+ not ok 5 - kmalloc_large_oob_right
When a test fails due to a missing KASAN report::
- # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:974
+ # kmalloc_double_kzfree: EXPECTATION FAILED at mm/kasan/kasan_test.c:709
KASAN failure expected in "kfree_sensitive(ptr)", but none occurred
- not ok 44 - kmalloc_double_kzfree
+ not ok 28 - kmalloc_double_kzfree
At the end the cumulative status of all KASAN tests is printed. On success::
@@ -534,7 +555,7 @@ There are a few ways to run KUnit-compatible KASAN tests.
1. Loadable module
With ``CONFIG_KUNIT`` enabled, KASAN-KUnit tests can be built as a loadable
- module and run by loading ``test_kasan.ko`` with ``insmod`` or ``modprobe``.
+ module and run by loading ``kasan_test.ko`` with ``insmod`` or ``modprobe``.
2. Built-In