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From: yangerkun <yangerkun@huawei.com>
To: <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>, <yi.zhang@huawei.com>,
	<houtao1@huawei.com>, <miaoxie@huawei.com>
Subject: system panic while dentry reference count overflow
Date: Mon, 6 May 2019 11:36:10 +0800	[thread overview]
Message-ID: <af9a8dec-98a2-896f-448b-04ded0af95f0@huawei.com> (raw)

Hi,

Run process parallel which each code show as below(2T memory), reference 
count of root dentry will overflow since allocation of negative dentry 
should do count++ for root dentry. Then, another dput of root dentry 
will free it, which cause crash of system. I wondered is there anyone 
has found this problem?

#include<stdlib.h> 

#include<stdio.h> 

#include<string.h> 

#include<time.h> 

 

int main() 

{ 

     const char *forname="_dOeSnotExist_.db"; 

     int i; 

     char filename[100]=""; 

     struct timespec time1 = {0, 0}; 

     for(;;) 

     { 

         clock_gettime(CLOCK_REALTIME, &time1); 

         for(i=0; i < 10000; i++) { 

 
sprintf(filename,"/%d%d%d%s",time1.tv_sec,time1.tv_nsec,i,forname); 

             access(filename,0); 

             memset(filename,'\0',100); 

         } 

     } 

     return 0; 

 

} 

~ 

Thanks,
Kun.


             reply	other threads:[~2019-05-06  3:36 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-06  3:36 yangerkun [this message]
2019-05-07  0:40 ` system panic while dentry reference count overflow Al Viro
2019-05-07  1:50   ` Linus Torvalds
2019-05-07  4:15     ` Al Viro
2019-05-07 15:26       ` Linus Torvalds
2019-05-07 19:16         ` Al Viro
2019-05-07 19:23           ` Linus Torvalds
2019-05-07 19:55             ` Al Viro
2019-05-07 20:47               ` Linus Torvalds
2019-05-07 21:14                 ` Al Viro

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