From: Jan Kara <jack@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Maxim Levitsky <mlevitsk@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Amir Goldstein <amir73il@gmail.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH] Revert "fs: Do not check if there is a fsnotify watcher on pseudo inodes"
Date: Mon, 29 Jun 2020 20:12:58 +0200 [thread overview]
Message-ID: <20200629181258.GI26507@quack2.suse.cz> (raw)
In-Reply-To: <20200629144145.GA3183@techsingularity.net>
On Mon 29-06-20 15:41:45, Mel Gorman wrote:
> This reverts commit e9c15badbb7b ("fs: Do not check if there is a
> fsnotify watcher on pseudo inodes"). The commit intended to eliminate
> fsnotify-related overhead for pseudo inodes but it is broken in
> concept. inotify can receive events of pipe files under /proc/X/fd and
> chromium relies on close and open events for sandboxing. Maxim Levitsky
> reported the following
>
> Chromium starts as a white rectangle, shows few white rectangles that
> resemble its notifications and then crashes.
>
> The stdout output from chromium:
>
> [mlevitsk@starship ~]$chromium-freeworld
> mesa: for the --simplifycfg-sink-common option: may only occur zero or one times!
> mesa: for the --global-isel-abort option: may only occur zero or one times!
> [3379:3379:0628/135151.440930:ERROR:browser_switcher_service.cc(238)] XXX Init()
> ../../sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.cc:**CRASHING**:seccomp-bpf failure in syscall 0072
> Received signal 11 SEGV_MAPERR 0000004a9048
>
> Crashes are not universal but even if chromium does not crash, it certainly
> does not work properly. While filtering just modify and access might be
> safe, the benefit is not worth the risk hence the revert.
>
> Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
> Fixes: e9c15badbb7b ("fs: Do not check if there is a fsnotify watcher on pseudo inodes")
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Thanks for the revert Mel. I can see Linus already picked it up so we are
done.
Honza
> ---
> fs/file_table.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/file_table.c b/fs/file_table.c
> index 65603502fed6..656647f9575a 100644
> --- a/fs/file_table.c
> +++ b/fs/file_table.c
> @@ -230,7 +230,7 @@ struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,
> d_set_d_op(path.dentry, &anon_ops);
> path.mnt = mntget(mnt);
> d_instantiate(path.dentry, inode);
> - file = alloc_file(&path, flags | FMODE_NONOTIFY, fops);
> + file = alloc_file(&path, flags, fops);
> if (IS_ERR(file)) {
> ihold(inode);
> path_put(&path);
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
prev parent reply other threads:[~2020-06-29 21:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-28 11:13 Commit 'fs: Do not check if there is a fsnotify watcher on pseudo inodes' breaks chromium here Maxim Levitsky
2020-06-28 12:53 ` Amir Goldstein
2020-06-28 13:14 ` Maxim Levitsky
2020-06-28 13:17 ` Maxim Levitsky
2020-06-28 13:34 ` Amir Goldstein
2020-06-29 9:31 ` Mel Gorman
2020-06-29 13:09 ` Jan Kara
2020-06-29 14:05 ` Amir Goldstein
2020-06-29 14:32 ` Mel Gorman
2020-06-29 14:41 ` [PATCH] Revert "fs: Do not check if there is a fsnotify watcher on pseudo inodes" Mel Gorman
2020-06-29 18:12 ` Jan Kara [this message]
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=20200629181258.GI26507@quack2.suse.cz \
--to=jack@suse.cz \
--cc=amir73il@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=mlevitsk@redhat.com \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
/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).