From: Jue Wang <juew@google.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: "Borislav Petkov" <bp@alien8.de>,
dinghui@sangfor.com.cn, huangcun@sangfor.com.cn,
linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org,
"HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
"Oscar Salvador" <osalvador@suse.de>, x86 <x86@kernel.org>,
"Song, Youquan" <youquan.song@intel.com>
Subject: Re: [PATCH 2/3] x86/mce: Avoid infinite loop for copy from user recovery
Date: Thu, 22 Jul 2021 06:54:37 -0700 [thread overview]
Message-ID: <CAPcxDJ7YsnYtyzSmgfBj-rmALkjigKx2ODB=SCYCzY8FJYg4iA@mail.gmail.com> (raw)
This patch assumes the UC error consumed in kernel is always the same UC.
Yet it's possible two UCs on different pages are consumed in a row.
The patch below will panic on the 2nd MCE. How can we make the code works
on multiple UC errors?
> + int count = ++current->mce_count;
> +
> + /* First call, save all the details */
> + if (count == 1) {
> + current->mce_addr = m->addr;
> + current->mce_kflags = m->kflags;
> + current->mce_ripv = !!(m->mcgstatus & MCG_STATUS_RIPV);
> + current->mce_whole_page = whole_page(m);
> + current->mce_kill_me.func = func;
> + }
> ......
> + /* Second or later call, make sure page address matches the one from first call */
> + if (count > 1 && (current->mce_addr >> PAGE_SHIFT) != (m->addr >> PAGE_SHIFT))
> + mce_panic("Machine checks to different user pages", m, msg);
next reply other threads:[~2021-07-22 13:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-22 13:54 Jue Wang [this message]
2021-07-22 15:19 ` [PATCH 2/3] x86/mce: Avoid infinite loop for copy from user recovery Luck, Tony
2021-07-22 23:30 ` Jue Wang
2021-07-23 0:14 ` Luck, Tony
2021-07-23 3:47 ` Jue Wang
2021-07-23 4:01 ` Luck, Tony
2021-07-23 4:16 ` Jue Wang
2021-07-23 14:47 ` Luck, Tony
-- strict thread matches above, loose matches on Subject: below --
2021-07-31 6:30 Jue Wang
2021-07-31 20:43 ` Luck, Tony
2021-08-02 15:29 ` Jue Wang
2021-07-06 19:06 [PATCH 0/3] More machine check recovery fixes Tony Luck
2021-07-06 19:06 ` [PATCH 2/3] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
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