From: weizhenliang <weizhenliang@huawei.com>
To: Sean Anderson <seanga2@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Changhee Han <ch0.han@lge.com>,
Tang Bin <tangbin@cmss.chinamobile.com>,
Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Subject: Re: [PATCH v2 1/2] tools/vm/page_owner_sort.c: Sort by stacktrace before culling
Date: Thu, 25 Nov 2021 09:46:41 +0000 [thread overview]
Message-ID: <22bad523dffb4681a201e6fedef7c50d@huawei.com> (raw)
On 2021/11/25 3:37, Sean Anderson <seanga2@gmail.com> wrote:
> static int compare_num(const void *p1, const void *p2) @@ -121,6
>+122,7 @@ static void add_list(char *buf, int len)
>list[list_size].page_num = get_page_num(buf);
>memcpy(list[list_size].txt, buf, len); list[list_size].txt[len] = 0;
>+ list[list_size].stacktrace = strchr(list[list_size].txt, '\n');
When read_block gets an empty line, buf is "\n", then the stacktrace is NULL
> list_size++;
> if (list_size % 1000 == 0) {
> printf("loaded %d\r", list_size);
>@@ -199,7 +201,7 @@ int main(int argc, char **argv)
>
> printf("sorting ....\n");
>
>- qsort(list, list_size, sizeof(list[0]), compare_txt);
>+ qsort(list, list_size, sizeof(list[0]), compare_stacktrace);
>
> list2 = malloc(sizeof(*list) * list_size); if (!list2) { @@ -211,7
>+213,7 @@ int main(int argc, char **argv)
>
> for (i = count = 0; i < list_size; i++) { if (count == 0 ||
>- strcmp(list2[count-1].txt, list[i].txt) != 0) {
>+ strcmp(list2[count-1].stacktrace, list[i].stacktrace) != 0) {
And when stacktrace is NULL, a segmentation fault will be triggered here.
> list2[count++] = list[i];
> } else {
> list2[count-1].num += list[i].num;
1. Maybe you can check whether the ret of read_block is 0 before add_list,
or whether the len of buf is 0 in add_list
2. Is it necessary to check stacktrace==NULL before use ?
Wei.
next reply other threads:[~2021-11-25 9:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 9:46 weizhenliang [this message]
2021-11-25 16:26 ` [PATCH v2 1/2] tools/vm/page_owner_sort.c: Sort by stacktrace before culling Sean Anderson
-- strict thread matches above, loose matches on Subject: below --
2021-11-24 19:37 Sean Anderson
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