linux/mm/kfence
huangshaobo 3c81b3bb0a kfence: enable check kfence canary on panic via boot param
Out-of-bounds accesses that aren't caught by a guard page will result in
corruption of canary memory.  In pathological cases, where an object has
certain alignment requirements, an out-of-bounds access might never be
caught by the guard page.  Such corruptions, however, are only detected on
kfree() normally.  If the bug causes the kernel to panic before kfree(),
KFENCE has no opportunity to report the issue.  Such corruptions may also
indicate failing memory or other faults.

To provide some more information in such cases, add the option to check
canary bytes on panic.  This might help narrow the search for the panic
cause; but, due to only having the allocation stack trace, such reports
are difficult to use to diagnose an issue alone.  In most cases, such
reports are inactionable, and is therefore an opt-in feature (disabled by
default).

[akpm@linux-foundation.org: add __read_mostly, per Marco]
Link: https://lkml.kernel.org/r/20220425022456.44300-1-huangshaobo6@huawei.com
Signed-off-by: huangshaobo <huangshaobo6@huawei.com>
Suggested-by: chenzefeng <chenzefeng2@huawei.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Wangbing <wangbing6@huawei.com>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13 07:20:06 -07:00
..
core.c kfence: enable check kfence canary on panic via boot param 2022-05-13 07:20:06 -07:00
kfence_test.c kfence: test: try to avoid test_gfpzero trigger rcu_stall 2022-03-22 15:57:11 -07:00
kfence.h mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
Makefile mm/kfence: remove unnecessary CONFIG_KFENCE option 2022-03-22 15:57:11 -07:00
report.c mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00