From: Linus Torvalds <torvalds@linux-foundation.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Eric Biggers <ebiggers@kernel.org>, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Ingo Molnar <mingo@redhat.com>, Hillf Danton <hdanton@sina.com>,
syzbot <syzbot+cdb5dd11c97cc532efad@syzkaller.appspotmail.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: psi_trigger_poll() is completely broken
Date: Mon, 10 Jan 2022 09:42:13 -0800 [thread overview]
Message-ID: <CAHk-=wiZ=oic3UfejGzy_31RYggtZWUeF1gE82_NHAA=ENY6Kw@mail.gmail.com> (raw)
In-Reply-To: <CAJuCfpHg=SPzx7SGUL75DVpMy0BDEwVj4o-SM0UKGmEJrOSdvg@mail.gmail.com>
On Mon, Jan 10, 2022 at 9:25 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> About the issue of serializing concurrent writes for
> cgroup_pressure_write() similar to how psi_write() does. Doesn't
> of->mutex inside kernfs_fop_write_iter() serialize the writes to the
> same file?
Ahh, yes, it looks like that does solve the serialization issue.
Sorry, I missed that because I'm not actually all that familiar with
the kernfs 'of' code.
So the only issue is the trigger lifetime one, and if a single trigger
is sufficient and returning -EBUSY for trying to replace an existing
one is good, then I think that's the proper fix.
I'm very busy with the merge window (and some upcoming travel and
family events), so I'm hoping somebody will write and test such a
patch. Please?
Linus
next prev parent reply other threads:[~2022-01-10 17:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000e8f8f505d0e479a5@google.com>
[not found] ` <20211211015620.1793-1-hdanton@sina.com>
2021-12-11 3:00 ` [syzbot] KASAN: use-after-free Read in remove_wait_queue (3) Eric Biggers
2022-01-05 15:20 ` psi_trigger_poll() is completely broken Eric Biggers
2022-01-05 18:50 ` Linus Torvalds
2022-01-05 19:07 ` Linus Torvalds
2022-01-05 19:13 ` Linus Torvalds
2022-01-06 22:05 ` Tejun Heo
2022-01-06 22:59 ` Linus Torvalds
2022-01-07 0:13 ` Eric Biggers
2022-01-07 3:02 ` Linus Torvalds
2022-01-10 13:45 ` Johannes Weiner
2022-01-10 17:25 ` Suren Baghdasaryan
2022-01-10 17:42 ` Linus Torvalds [this message]
2022-01-10 18:19 ` Suren Baghdasaryan
2022-01-11 3:02 ` Suren Baghdasaryan
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