From: Andi Kleen <ak@linux.intel.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>, 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: Tue, 10 Oct 2017 13:13:58 -0700 [thread overview]
Message-ID: <871smasqux.fsf@linux.intel.com> (raw)
"Luck, Tony" <tony.luck@intel.com> writes:
>> for (;;) {
>> entry = mce_log_get_idx_check(mcelog.next);
>
> Can't this get even simpler? Do we need the loop? The mutex
> will now protect us while we check to see if there is a slot
> to stash this new entry. Also just say:
IMHO the warning is just bogus. There's nothing here that actually
uses RCU. I would just remove it.
>> if (entry >= MCE_LOG_LEN) {
>> - set_bit(MCE_OVERFLOW,
>> - (unsigned long *)&mcelog.flags);
>> + set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog.flags);
>
> Need to mutex_unlock(&mce_chrdev_read_mutex); here.
And yes that too.
-Andi
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WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <ak@linux.intel.com>
To: "Luck\, Tony" <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>, 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: Re: x86/mce: suspicious RCU usage in 4.13.4
Date: Tue, 10 Oct 2017 13:13:58 -0700 [thread overview]
Message-ID: <871smasqux.fsf@linux.intel.com> (raw)
In-Reply-To: <20171010200841.uhniuwc7pulqgmic@intel.com> (Tony Luck's message of "Tue, 10 Oct 2017 13:08:41 -0700")
"Luck, Tony" <tony.luck@intel.com> writes:
>> for (;;) {
>> entry = mce_log_get_idx_check(mcelog.next);
>
> Can't this get even simpler? Do we need the loop? The mutex
> will now protect us while we check to see if there is a slot
> to stash this new entry. Also just say:
IMHO the warning is just bogus. There's nothing here that actually
uses RCU. I would just remove it.
>> if (entry >= MCE_LOG_LEN) {
>> - set_bit(MCE_OVERFLOW,
>> - (unsigned long *)&mcelog.flags);
>> + set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog.flags);
>
> Need to mutex_unlock(&mce_chrdev_read_mutex); here.
And yes that too.
-Andi
next reply other threads:[~2017-10-10 20:13 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-10 20:13 Andi Kleen [this message]
2017-10-10 20:13 ` x86/mce: suspicious RCU usage in 4.13.4 Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2017-11-01 20:07 Luck, Tony
2017-11-01 20:07 ` Luck, Tony
2017-11-01 16:47 Borislav Petkov
2017-11-01 16:47 ` Borislav Petkov
2017-11-01 20:28 ` [tip:ras/urgent] x86/mcelog: Get rid of RCU remnants tip-bot for Borislav Petkov
2017-11-01 14:56 x86/mce: suspicious RCU usage in 4.13.4 Laura Abbott
2017-11-01 14:56 ` Laura Abbott
2017-10-16 18:28 Luck, Tony
2017-10-16 18:28 ` Luck, Tony
2017-10-15 9:40 Borislav Petkov
2017-10-15 9:40 ` Borislav Petkov
2017-10-12 22:13 Andi Kleen
2017-10-12 22:13 ` Andi Kleen
2017-10-12 9:02 Borislav Petkov
2017-10-12 9:02 ` Borislav Petkov
2017-10-11 23:11 Andi Kleen
2017-10-11 23:11 ` Andi Kleen
2017-10-11 21:34 Luck, Tony
2017-10-11 21:34 ` Luck, Tony
2017-10-11 11:50 Borislav Petkov
2017-10-11 11:50 ` Borislav Petkov
2017-10-10 20:08 Luck, Tony
2017-10-10 20:08 ` Luck, Tony
2017-10-10 19:44 Borislav Petkov
2017-10-10 19:44 ` Borislav Petkov
2017-10-10 19:00 Jeremy Cline
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