Linux-ext4 Archive mirror
 help / color / mirror / Atom feed

From: bugzilla-daemon@kernel.org
To: linux-ext4@vger.kernel.org
Subject: [Bug 218830] New: lseek on closed file does not trigger an error and affect other files
Date: Mon, 13 May 2024 02:39:59 +0000	[thread overview]
Message-ID: <bug-218830-13602@https.bugzilla.kernel.org/> (raw)

https://bugzilla.kernel.org/show_bug.cgi?id=218830

            Bug ID: 218830
           Summary: lseek on closed file does not trigger an error and
                    affect other files
           Product: File System
           Version: 2.5
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P3
         Component: ext4
          Assignee: fs_ext4@kernel-bugs.osdl.org
          Reporter: zhangchi_seg@smail.nju.edu.cn
        Regression: No

Created attachment 306289
  --> https://bugzilla.kernel.org/attachment.cgi?id=306289&action=edit
reproduce.c

Hi,

I have a file and lseek on it after calling the close(), but it dose not
trigger an EBADF error. Then I open and write to another file, but the write
operation trigger an "Invalid argument" error. I can reproduce this with the
latest linux kernel https://git.kernel.org/torvalds/t/linux-6.9-rc7.tar.gz

The following is the triggering script:
```
dd if=/dev/zero of=ext4-0.img bs=1M count=120
mkfs.ext4 ext4-0.img
g++ -static reproduce.c
losetup /dev/loop0 ext4-0.img
mkdir /root/mnt
./a.out
```
After running the script, you will see an error message:
```
write failure: (Invalid argument)
```

The contents of `reproduce.c` :
```
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <stddef.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include <dirent.h>

#include <string>

#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <sys/xattr.h>
#include <sys/mount.h>
#include <sys/statfs.h>
#include <fcntl.h>

#define ALIGN 4096

void* align_alloc(size_t size) {
    void *ptr = NULL;
    int ret = posix_memalign(&ptr, ALIGN, size);
    if (ret) {
      printf("align error\n");
      exit(1);
    }
    return ptr;
}

int main()
{
    mount("/dev/loop0", "/root/mnt", "ext4", 0, "");

    creat("/root/mnt/a", S_IRWXU);
    creat("/root/mnt/b", S_IRWXU);
    int fd_a = open("/root/mnt/a", O_RDWR); 
    close(fd_a); 
    int fd_b = open("/root/mnt/b", O_RDWR | O_DIRECT); 
    int state = lseek(fd_a, 7208, SEEK_SET); 
    if (state == -1) {
      printf("lseek failure: (%s)\n", strerror(errno));
    }

    char *buf = (char*)align_alloc(4096);
    memset(buf, 'a', 4096);
    state = write(fd_b, buf, 4096);
    if (state == -1) {
      printf("write failure: (%s)\n", strerror(errno));
    }

    close(fd_b); 
    return 0;
}
```

I also found that if I remove the `O_DIRECT` flag of file b, the write
operation will not trigger an error, but the contents of b become garbled.

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are watching the assignee of the bug.

next             reply	other threads:[~2024-05-13  2:40 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-13  2:39 bugzilla-daemon [this message]
2024-05-13 13:24 ` [Bug 218830] lseek on closed file does not trigger an error and affect other files bugzilla-daemon
2024-05-13 14:36 ` bugzilla-daemon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=bug-218830-13602@https.bugzilla.kernel.org/ \
    --to=bugzilla-daemon@kernel.org \
    --cc=linux-ext4@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).