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: kasan_save_stack+0x24/0x50 kasan_set_track+0x24/0x38 kasan_set_free_info+0x18/0x20 __kasan_slab_free+0x10c/0x170 kasan_slab_free+0x10/0x18 kfree+0x98/0x270 kasan_rcu_reclaim+0x1c/0x60 Last call_rcu(): kasan_save_stack+0x24/0x50 kasan_record_aux_stack+0xbc/0xd0 call_rcu+0x8c/0x580 kasan_rcu_uaf+0xf4/0xf8 Generic KASAN will record the last two call_rcu() call stacks and print up to 2 call_rcu() call stacks in KASAN report. it is only suitable for generic KASAN. This feature considers the size of struct kasan_alloc_meta and kasan_free_meta, we try to optimize the structure layout and size , lets it get better memory consumption. [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 v1: - 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 Changes since v2: - change recording from first/last to the last two call stacks - move free track into kasan free meta - init slab_free_meta on object slot creation - modify documentation Changes since v3: - change variable name to be more clearly - remove the redundant condition - remove init free meta-data and increasing object condition Changes since v4: - add a macro KASAN_KMALLOC_FREETRACK in order to check whether print free stack - change printing message - remove descriptions in Kocong.kasan Changes since v5: - reuse print_stack() in print_track() Changes since v6: - fix typo - renamed the variable name in testcase Walter Wu (4): rcu: kasan: record and print call_rcu() call stack kasan: record and print the free track kasan: add tests for call_rcu stack recording kasan: update documentation for generic kasan Documentation/dev-tools/kasan.rst | 3 +++ include/linux/kasan.h | 2 ++ kernel/rcu/tree.c | 2 ++ lib/test_kasan.c | 30 ++++++++++++++++++++++++++++++ mm/kasan/common.c | 26 ++++---------------------- mm/kasan/generic.c | 43 +++++++++++++++++++++++++++++++++++++++++++ mm/kasan/generic_report.c | 1 + mm/kasan/kasan.h | 23 +++++++++++++++++++++-- mm/kasan/quarantine.c | 1 + mm/kasan/report.c | 54 +++++++++++++++++++++++++++--------------------------- mm/kasan/tags.c | 37 +++++++++++++++++++++++++++++++++++++ 11 files changed, 171 insertions(+), 51 deletions(-)
