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 one call_rcu() call stack:
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
, let 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 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
Changes since v3:
- 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
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/Kconfig.kasan | 2 ++
lib/test_kasan.c | 30 ++++++++++++++++++++++++++++++
mm/kasan/common.c | 37 ++++++++++++-------------------------
mm/kasan/generic.c | 38 ++++++++++++++++++++++++++++++++++++++
mm/kasan/kasan.h | 17 +++++++++++++++++
mm/kasan/report.c | 36 ++++++++++++++++++++----------------
mm/kasan/tags.c | 37 +++++++++++++++++++++++++++++++++++++
10 files changed, 163 insertions(+), 41 deletions(-)