kasan: increase the number of bits to shift when recording extra timestamps
authorJuntong Deng <juntong.deng@outlook.com>
Thu, 15 Feb 2024 18:39:55 +0000 (18:39 +0000)
committerAndrew Morton <akpm@linux-foundation.org>
Thu, 22 Feb 2024 23:27:20 +0000 (15:27 -0800)
commit952237b5a9b79acf1212b40ad1e993557e3cb0ca
treed580e12f93960eea9d2e17d8257207bce102ffbb
parent059ab7be09d4ff0cab4f43ffbf225a2693da0bd7
kasan: increase the number of bits to shift when recording extra timestamps

In 5d4c6ac94694 ("kasan: record and report more information") I thought
that printk only displays a maximum of 99999 seconds, but actually printk
can display a larger number of seconds.

So increase the number of bits to shift when recording the extra timestamp
(44 bits), without affecting the precision, shift it right by 9 bits,
discarding all bits that do not affect the microsecond part (nanoseconds
will not be shown).

Currently the maximum time that can be displayed is 9007199.254740s,
because

11111111111111111111111111111111111111111111 (44 bits) << 9
= 11111111111111111111111111111111111111111111000000000
9007199.254740

Link: https://lkml.kernel.org/r/AM6PR03MB58481629F2F28CE007412139994D2@AM6PR03MB5848.eurprd03.prod.outlook.com
Fixes: 5d4c6ac94694 ("kasan: record and report more information")
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/kasan/common.c
mm/kasan/report.c