EDAC/skx_common: Fix general protection fault

[ Upstream commit 20d2d476b3ae18041be423671a8637ed5ffd6958 ]

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@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Tested-by: Feng Xu <feng.f.xu@intel.com>
Link: https://lore.kernel.org/r/20250417150724.1170168-2-qiuxu.zhuo@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/edac/skx_common.c b/drivers/edac/skx_common.c
index 85ec3196664d..88f5ff249f2e 100644
--- a/drivers/edac/skx_common.c
+++ b/drivers/edac/skx_common.c
@@ -115,6 +115,7 @@ EXPORT_SYMBOL_GPL(skx_adxl_get);
 
 void skx_adxl_put(void)
 {
+	adxl_component_count = 0;
 	kfree(adxl_values);
 	kfree(adxl_msg);
 }