From: Al Viro <viro@zeniv.linux.org.uk>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: gfs2@lists.linux.dev
Subject: Re: [PATCH 0/9] gfs2: Bugs in "Use GL_NOBLOCK flag for non-blocking lookups"
Date: Sat, 20 Jan 2024 01:36:39 +0000 [thread overview]
Message-ID: <20240120013639.GB2087318@ZenIV> (raw)
In-Reply-To: <20240119212056.805617-1-agruenba@redhat.com>
On Fri, Jan 19, 2024 at 10:20:47PM +0100, Andreas Gruenbacher wrote:
> Hello,
>
> Al Viro has reported issues with commit dd00aaeb3432 ("gfs2: Use
> GL_NOBLOCK flag for non-blocking lookups"):
>
> * First, parent can now be NULL and dereferencing it in
> gfs2_dir_check(d_inode(parent), &dentry->d_name, ip) isn't going to
> work;
Nit: parent can't be NULL; what can be NULL in RCU mode is d_inode(parent) when
sampled inside ->d_revalidate(). IOW, it's not d_inode(parent) evaluation
that breaks, but passing the resulting NULL inode pointer to gfs2_dir_check().
> * Second, gfs2_dir_check() can still sleep, which breaks LOOKUP_RCU
> mode.
>
> These patches should fix both of these problems. We'll either need
> these fixes added, or commit dd00aaeb3432 reverted for now.
next prev parent reply other threads:[~2024-01-20 1:36 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-19 21:20 [PATCH 0/9] gfs2: Bugs in "Use GL_NOBLOCK flag for non-blocking lookups" Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 1/9] gfs2: Fix gfs2_drevalidate NULL pointer dereference Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 2/9] gfs2: Pass FGP flags to gfs2_getbuf Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 3/9] gfs2: Split gfs2_meta_read_async off from gfs2_meta_read Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 4/9] gfs2: Add FGP_NOWAIT support to gfs2_meta_read_async Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 5/9] gfs2: Pass FGP flags to gfs2_meta_{,inode_}buffer Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 6/9] gfs2: Pass FGP flags to gfs2_dirent_search Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 7/9] gfs2: Pass FGP flags to gfs2_dir_check Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 8/9] gfs2: Minor gfs2_drevalidate cleanup Andreas Gruenbacher
2024-01-19 21:20 ` [PATCH 9/9] gfs2: Fix LOOKUP_RCU support in gfs2_drevalidate Andreas Gruenbacher
2024-01-20 1:36 ` Al Viro [this message]
2024-01-20 1:38 ` [PATCH 0/9] gfs2: Bugs in "Use GL_NOBLOCK flag for non-blocking lookups" Al Viro
2024-01-22 12:52 ` Andrew Price
2024-02-02 4:23 ` Al Viro
2024-02-02 4:34 ` Al Viro
2024-02-02 16:32 ` Andreas Gruenbacher
2024-02-02 4:59 ` Al Viro
2024-02-02 5:02 ` Al Viro
2024-02-02 17:09 ` Andreas Gruenbacher
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