[090/114] kasan: add comment about UACCESS regions to kasan_report

Commit Message

Andrew Morton March 25, 2022, 1:13 a.m. UTC

From: Andrey Konovalov <[e-mail]>
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/12[e-mail]
Signed-off-by: Andrey Konovalov <[e-mail]>
Cc: Alexander Potapenko <[e-mail]>
Cc: Andrey Ryabinin <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: Marco Elver <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/kasan/report.c |    5 +++++
 1 file changed, 5 insertions(+)

Patch

--- 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)
 {