This patchset improves KASAN reports by making them to have call_rcu() call stack information. It is helpful 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) Add new CONFIG option to record first and last call_rcu() call stack and KASAN report prints two call_rcu() call stack. This option 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 Walter Wu (3): rcu/kasan: record and print call_rcu() call stack kasan: record and print the free track kasan: add KASAN_RCU_STACK_RECORD documentation Documentation/dev-tools/kasan.rst | 21 +++++++++++++++++++++ include/linux/kasan.h | 7 +++++++ kernel/rcu/tree.c | 5 +++++ lib/Kconfig.kasan | 11 +++++++++++ mm/kasan/common.c | 31 +++++++++++++++++++++++++++++++ mm/kasan/kasan.h | 12 ++++++++++++ mm/kasan/report.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++------- 7 files changed, 133 insertions(+), 7 deletions(-)
