From: Al Viro <viro@zeniv.linux.org.uk>
To: haosdent <haosdent@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
zhengyu.duan@shopee.com, Haosong Huang <huangh@sea.com>
Subject: Re: NULL pointer dereference when access /proc/net
Date: Sun, 25 Apr 2021 16:50:54 +0000 [thread overview]
Message-ID: <YIWd7v1U/dGivmSE@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <CAFt=RON+KYYf5yt9vM3TdOSn4zco+3XtFyi3VDRr1vbQUBPZ0g@mail.gmail.com>
On Sun, Apr 25, 2021 at 11:22:15PM +0800, haosdent wrote:
> Hi, Alexander Viro and dear Linux Filesystems maintainers, recently we
> encounter a NULL pointer dereference Oops in our production.
>
> We have attempted to analyze the core dump and compare it with source code
> in the past few weeks, currently still could not understand why
> `dentry->d_inode` become NULL while other fields look normal.
Not really - the crucial part is ->d_count == -128, i.e. it's already past
__dentry_kill().
> [19521409.514784] RIP: 0010:__atime_needs_update+0x5/0x190
Which tree is that? __atime_needs_update() had been introduced in
4.8 and disappeared in 4.18; anything of that age straight on mainline
would have a plenty of interesting problems. If you have some patches
applied on top of that... Depends on what those are, obviously.
next parent reply other threads:[~2021-04-25 16:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAFt=RON+KYYf5yt9vM3TdOSn4zco+3XtFyi3VDRr1vbQUBPZ0g@mail.gmail.com>
2021-04-25 16:50 ` Al Viro [this message]
2021-04-25 17:04 ` NULL pointer dereference when access /proc/net haosdent
2021-04-25 17:14 ` haosdent
2021-04-25 17:22 ` Al Viro
2021-04-25 18:00 ` haosdent
2021-04-25 18:15 ` haosdent
2021-04-26 17:16 ` haosdent
2021-04-26 17:30 ` Al Viro
2021-05-03 15:31 ` haosdent
2021-05-06 10:21 ` haosdent
2021-04-25 15:47 haosdent
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=YIWd7v1U/dGivmSE@zeniv-ca.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=haosdent@gmail.com \
--cc=huangh@sea.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=zhengyu.duan@shopee.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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 NNTP newsgroup(s).