From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan: add comment about UACCESS regions to kasan_report Add a comment explaining why kasan_report() is the only reporting function that uses user_access_save/restore(). Link: https://lkml.kernel.org/r/1201ca3c2be42c7bd077c53d2e46f4a51dd1476a.1646237226.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/kasan/report.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/mm/kasan/report.c~kasan-add-comment-about-uaccess-regions-to-kasan_report +++ a/mm/kasan/report.c @@ -430,6 +430,11 @@ void kasan_report_invalid_free(void *ptr end_report(&flags, ptr); } +/* + * kasan_report() is the only reporting function that uses + * user_access_save/restore(): kasan_report_invalid_free() cannot be called + * from a UACCESS region, and kasan_report_async() is not used on x86. + */ bool kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) { _
