[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-Id: <20230719211625.298785-1-tony.luck@intel.com>
Date: Wed, 19 Jul 2023 14:16:25 -0700
From: Tony Luck <tony.luck@...el.com>
To: Borislav Petkov <bp@...en8.de>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@....com>,
"Li, Zhiquan1" <zhiquan1.li@...el.com>,
"Song, Youquan" <youquan.song@...el.com>, x86@...nel.org,
linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
patches@...ts.linux.dev, Tony Luck <tony.luck@...el.com>
Subject: [PATCH v2] x86/mce: Set PG_hwpoison page flag to avoid the capture kernel panic
From: Zhiquan Li <zhiquan1.li@...el.com>
Kdump can exclude the HWPosion page to avoid touch the error page
again, the prerequisite is the PG_hwpoison page flag is set.
However, for some MCE fatal error cases, there are no opportunity
to queue a task for calling memory_failure(), as a result,
the capture kernel touches the error page again and panics.
Add function mce_set_page_hwpoison_now() which mark a page as
HWPoison before kernel panic() for MCE error, so that the dump
program can check and skip the error page and prevent the capture
kernel panic.
[Tony: Changed TestSetPageHWPoison() to SetPageHWPoison()]
Co-developed-by: Youquan Song <youquan.song@...el.com>
Signed-off-by: Youquan Song <youquan.song@...el.com>
Signed-off-by: Zhiquan Li <zhiquan1.li@...el.com>
Signed-off-by: Tony Luck <tony.luck@...el.com>
---
v2: Replaced "TODO" comment in code with comments based on mailing
list discussion on the lack of value in covering other page types
arch/x86/kernel/cpu/mce/core.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 89e2aab5d34d..766f64fade51 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -156,6 +156,30 @@ void mce_unregister_decode_chain(struct notifier_block *nb)
}
EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);
+/*
+ * Kdump can exclude the HWPosion page to avoid touch the error page again,
+ * the prerequisite is the PG_hwpoison page flag is set. However, for some
+ * MCE fatal error cases, there are no opportunity to queue a task
+ * for calling memory_failure(), as a result, the capture kernel panic.
+ * This function mark the page as HWPoison before kernel panic() for MCE.
+ *
+ * This covers normal 4KByte pages. There is little/no value in covering
+ * other page types. E.g.
+ * SGX: These cannot be dumped.
+ * PMEM: Pointless to dump these. Persistent memory contents remain
+ * available across reboots.
+ * HugeTLB: These are user pages. Generally filtered out of the kdump
+ * to keep size small. Not helpful to debug kernel issues.
+ */
+static void mce_set_page_hwpoison_now(unsigned long pfn)
+{
+ struct page *p;
+
+ p = pfn_to_online_page(pfn);
+ if (p)
+ SetPageHWPoison(p);
+}
+
static void __print_mce(struct mce *m)
{
pr_emerg(HW_ERR "CPU %d: Machine Check%s: %Lx Bank %d: %016Lx\n",
@@ -286,6 +310,8 @@ static noinstr void mce_panic(const char *msg, struct mce *final, char *exp)
if (!fake_panic) {
if (panic_timeout == 0)
panic_timeout = mca_cfg.panic_timeout;
+ if (final && (final->status & MCI_STATUS_ADDRV))
+ mce_set_page_hwpoison_now(final->addr >> PAGE_SHIFT);
panic(msg);
} else
pr_emerg(HW_ERR "Fake kernel panic: %s\n", msg);
--
2.40.1
Powered by blists - more mailing lists