linux-kernel - Re: [PATCH 34/33] netfs: Use in_interrupt() not in

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210216084230.GA23669@lst.de>
Date:   Tue, 16 Feb 2021 09:42:30 +0100
From:   Christoph Hellwig <hch@....de>
To:     David Howells <dhowells@...hat.com>
Cc:     Trond Myklebust <trondmy@...merspace.com>,
        Marc Dionne <marc.dionne@...istor.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        Steve French <sfrench@...ba.org>,
        Dominique Martinet <asmadeus@...ewreck.org>,
        linux-cifs@...r.kernel.org, ceph-devel@...r.kernel.org,
        Jeff Layton <jlayton@...hat.com>,
        Matthew Wilcox <willy@...radead.org>, linux-cachefs@...hat.com,
        Alexander Viro <viro@...iv.linux.org.uk>, linux-mm@...ck.org,
        linux-afs@...ts.infradead.org,
        v9fs-developer@...ts.sourceforge.net,
        Christoph Hellwig <hch@....de>, linux-fsdevel@...r.kernel.org,
        linux-nfs@...r.kernel.org, Jeff Layton <jlayton@...nel.org>,
        David Wysochanski <dwysocha@...hat.com>,
        linux-kernel@...r.kernel.org,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: Re: [PATCH 34/33] netfs: Use in_interrupt() not in_softirq()

On Mon, Feb 15, 2021 at 10:46:23PM +0000, David Howells wrote:
> The in_softirq() in netfs_rreq_terminated() works fine for the cache being
> on a normal disk, as the completion handlers may get called in softirq
> context, but for an NVMe drive, the completion handler may get called in
> IRQ context.
> 
> Fix to use in_interrupt() instead of in_softirq() throughout the read
> helpers, particularly when deciding whether to punt code that might sleep
> off to a worker thread.

We must not use either check, as they all are unreliable especially
for PREEMPT-RT.