This patchset improves KASAN reports by making them to have call_rcu() call stack information. It is useful for programmers to solve use-after-free or double-free memory issue. The KASAN report was as follows(cleaned up slightly): BUG: KASAN: use-after-free in kasan_rcu_reclaim+0x58/0x60 Freed by task 0: save_stack+0x24/0x50 __kasan_slab_free+0x110/0x178 kasan_slab_free+0x10/0x18 kfree+0x98/0x270 kasan_rcu_reclaim+0x1c/0x60 rcu_core+0x8b4/0x10f8 rcu_core_si+0xc/0x18 efi_header_end+0x238/0xa6c First call_rcu() call stack: save_stack+0x24/0x50 kasan_record_callrcu+0xc8/0xd8 call_rcu+0x190/0x580 kasan_rcu_uaf+0x1d8/0x278 Last call_rcu() call stack: (stack is not available) Generic KASAN will record first and last call_rcu() call stack and print two call_rcu() call stack in KASAN report. This feature doesn't increase the cost of memory consumption. It is only suitable for generic KASAN. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ Changes since v2: - remove new config option, default enable it in generic KASAN - test this feature in SLAB/SLUB, it is pass. - modify macro to be more clearly - modify documentation Walter Wu (3): rcu/kasan: record and print call_rcu() call stack kasan: record and print the free track kasan: update documentation for generic kasan Documentation/dev-tools/kasan.rst | 6 ++++++ include/linux/kasan.h | 2 ++ kernel/rcu/tree.c | 4 ++++ lib/Kconfig.kasan | 2 ++ mm/kasan/common.c | 26 ++++---------------------- mm/kasan/generic.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ mm/kasan/kasan.h | 23 +++++++++++++++++++++++ mm/kasan/report.c | 47 +++++++++++++++++++++-------------------------- mm/kasan/tags.c | 37 +++++++++++++++++++++++++++++++++++++ 9 files changed, 149 insertions(+), 48 deletions(-)
