linux-kernel - [PATCH 1/7] EDAC/skx_common: Fix general protection fault

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Message-ID: <20250417150724.1170168-2-qiuxu.zhuo@intel.com>
Date: Thu, 17 Apr 2025 23:07:18 +0800
From: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
To: Tony Luck <tony.luck@...el.com>
Cc: Qiuxu Zhuo <qiuxu.zhuo@...el.com>,
	Feng Xu <feng.f.xu@...el.com>,
	Borislav Petkov <bp@...en8.de>,
	James Morse <james.morse@....com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Robert Richter <rric@...nel.org>,
	Yi Lai <yi1.lai@...el.com>,
	Shawn Fan <shawn.fan@...el.com>,
	linux-edac@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/7] EDAC/skx_common: Fix general protection fault

After loading i10nm_edac (which automatically loads skx_edac_common), if
unload only i10nm_edac, then reload it and perform error injection testing,
a general protection fault may occur:

  mce: [Hardware Error]: Machine check events logged
  Oops: general protection fault ...
  ...
  Workqueue: events mce_gen_pool_process
  RIP: 0010:string+0x53/0xe0
  ...
  Call Trace:
  <TASK>
  ? die_addr+0x37/0x90
  ? exc_general_protection+0x1e7/0x3f0
  ? asm_exc_general_protection+0x26/0x30
  ? string+0x53/0xe0
  vsnprintf+0x23e/0x4c0
  snprintf+0x4d/0x70
  skx_adxl_decode+0x16a/0x330 [skx_edac_common]
  skx_mce_check_error.part.0+0xf8/0x220 [skx_edac_common]
  skx_mce_check_error+0x17/0x20 [skx_edac_common]
  ...

The issue arose was because the variable 'adxl_component_count' (inside
skx_edac_common), which counts the ADXL components, was not reset. During
the reloading of i10nm_edac, the count was incremented by the actual number
of ADXL components again, resulting in a count that was double the real
number of ADXL components. This led to an out-of-bounds reference to the
ADXL component array, causing the general protection fault above.

Fix this issue by resetting the 'adxl_component_count' in adxl_put(),
which is called during the unloading of {skx,i10nm}_edac.

Fixes: 123b15863550 ("EDAC, i10nm: make skx_common.o a separate module")
Reported-by: Feng Xu <feng.f.xu@...el.com>
Tested-by: Feng Xu <feng.f.xu@...el.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
---
 drivers/edac/skx_common.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/edac/skx_common.c b/drivers/edac/skx_common.c
index fa5b442b1844..c9ade45c1a99 100644
--- a/drivers/edac/skx_common.c
+++ b/drivers/edac/skx_common.c
@@ -116,6 +116,7 @@ EXPORT_SYMBOL_GPL(skx_adxl_get);

 void skx_adxl_put(void)
 {
+	adxl_component_count = 0;
 	kfree(adxl_values);
 	kfree(adxl_msg);
 }
-- 
2.43.0