From 952237b5a9b79acf1212b40ad1e993557e3cb0ca Mon Sep 17 00:00:00 2001 From: Juntong Deng Date: Thu, 15 Feb 2024 18:39:55 +0000 Subject: [PATCH] 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 Acked-by: Andrey Konovalov Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- mm/kasan/common.c | 2 +- mm/kasan/report.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 610efae91220..f2747ed30da0 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -55,7 +55,7 @@ void kasan_set_track(struct kasan_track *track, depot_stack_handle_t stack) u64 ts_nsec = local_clock(); track->cpu = cpu; - track->timestamp = ts_nsec >> 3; + track->timestamp = ts_nsec >> 9; #endif /* CONFIG_KASAN_EXTRA_INFO */ track->pid = current->pid; track->stack = stack; diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 7afa4feb03e1..b48c768acc84 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -267,7 +267,7 @@ static void print_track(struct kasan_track *track, const char *prefix) u64 ts_nsec = track->timestamp; unsigned long rem_usec; - ts_nsec <<= 3; + ts_nsec <<= 9; rem_usec = do_div(ts_nsec, NSEC_PER_SEC) / 1000; pr_err("%s by task %u on cpu %d at %lu.%06lus:\n",