From: Qian Cai <cai@lca.pw>
To: Matthew Wilcox <willy@infradead.org>
Cc: darrick.wong@oracle.com, hch@infradead.org,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] iomap: Fix WARN_ON_ONCE() from unprivileged users
Date: Mon, 31 Aug 2020 14:05:13 -0400 [thread overview]
Message-ID: <20200831180513.GC4080@lca.pw> (raw)
In-Reply-To: <20200831174219.GI14765@casper.infradead.org>
On Mon, Aug 31, 2020 at 06:42:19PM +0100, Matthew Wilcox wrote:
> On Mon, Aug 31, 2020 at 01:25:34PM -0400, Qian Cai wrote:
> > + case IOMAP_DELALLOC:
> > + /*
> > + * DIO is not serialised against mmap() access at all, and so
> > + * if the page_mkwrite occurs between the writeback and the
> > + * iomap_apply() call in the DIO path, then it will see the
> > + * DELALLOC block that the page-mkwrite allocated.
> > + */
> > + path = file_path(dio->iocb->ki_filp, pathname,
> > + sizeof(pathname));
> > + if (IS_ERR(path))
> > + path = "(unknown)";
> > +
> > + pr_warn_ratelimited("Direct I/O collision with buffered writes! File: %s Comm: %.20s\n",
> > + path, current->comm);
>
> "File: %pD4"?
Sounds like a good idea. I could use that.
prev parent reply other threads:[~2020-08-31 18:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 17:25 [PATCH v3] iomap: Fix WARN_ON_ONCE() from unprivileged users Qian Cai
2020-08-31 17:26 ` Christoph Hellwig
2020-08-31 17:42 ` Matthew Wilcox
2020-08-31 18:05 ` Qian Cai [this message]
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