From: Andi Kleen <ak@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "Luck, Tony" <tony.luck@intel.com>,
Jeremy Cline <jcline@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-edac@vger.kernel.org,
linux-kernel@vger.kernel.org, Laura Abbott <labbott@redhat.com>
Subject: x86/mce: suspicious RCU usage in 4.13.4
Date: Wed, 11 Oct 2017 16:11:37 -0700 [thread overview]
Message-ID: <20171011231137.GI5109@tassilo.jf.intel.com> (raw)
> - next = mce_log_get_idx_check(mcelog.next);
> + next = mcelog.next;
>
> /* Only supports full reads right now */
> err = -EINVAL;
> @@ -281,8 +266,6 @@ static ssize_t mce_chrdev_read(struct file *filp, char __user *ubuf,
> next = cmpxchg(&mcelog.next, prev, 0);
> } while (next != prev);
>
> - synchronize_sched();
Sorry I take back what I wrote earlier. This RCU is actually still needed,
otherwise the reader could see partially written entries.
So rather have to keep that, and change the read code to run with rcu_read_lock()
-Andi
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next reply other threads:[~2017-10-11 23:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-11 23:11 Andi Kleen [this message]
-- strict thread matches above, loose matches on Subject: below --
2017-11-01 20:07 x86/mce: suspicious RCU usage in 4.13.4 Luck, Tony
2017-11-01 16:47 Borislav Petkov
2017-11-01 14:56 Laura Abbott
2017-10-16 18:28 Luck, Tony
2017-10-15 9:40 Borislav Petkov
2017-10-12 22:13 Andi Kleen
2017-10-12 9:02 Borislav Petkov
2017-10-11 21:34 Luck, Tony
2017-10-11 11:50 Borislav Petkov
2017-10-10 20:13 Andi Kleen
2017-10-10 20:08 Luck, Tony
2017-10-10 19:44 Borislav Petkov
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