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
, 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
Changes since v4:
- change variable name to be more clearly
- remove the redundant condition
- remove init free meta-data and increasing object condition
Changes since v5:
- add a macro KASAN_KMALLOC_FREETRACK in order to check whether
print free stack
- change printing message
- remove descriptions in Kocong.kasan
Changes since v6:
- reuse print_stack() in print_track()
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(-)
On Fri, May 22, 2020 at 3:58 AM Walter Wu <[email protected]> wrote:
>
> 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
> , 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
Reviewed-by: Andrey Konovalov <[email protected]>
for the series.
Thanks!
>
> 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
>
> Changes since v4:
> - change variable name to be more clearly
> - remove the redundant condition
> - remove init free meta-data and increasing object condition
>
> Changes since v5:
> - add a macro KASAN_KMALLOC_FREETRACK in order to check whether
> print free stack
> - change printing message
> - remove descriptions in Kocong.kasan
>
> Changes since v6:
> - reuse print_stack() in print_track()
>
> 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(-)
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20200522015757.22267-1-walter-zh.wu%40mediatek.com.