[PATCH 0/1][SRU][N] UBSAN: shift-out-of-bounds in drivers/edac/skx_common.c:452:16

[AceLan Kao]

From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/2119713

[Impact]
Shows the following UBSAN warning messages in dmesg

Jul 21 08:37:25 localhost kernel: UBSAN: shift-out-of-bounds in /build/linux-oem-6.14-44jeWy/linux-oem-6.14-6.14.0/drivers/edac/skx_common.c:452:16
Jul 21 08:37:25 localhost kernel: shift exponent -66 is negative
Jul 21 08:37:25 localhost kernel: CPU: 79 UID: 0 PID: 2454 Comm: (udev-worker) Not tainted 6.14.0-1006-oem #6-Ubuntu
Jul 21 08:37:25 localhost kernel: Hardware name: Dell Inc. Dell Pro Max Tower T6 FCT6260/, BIOS 0.9.39 07/09/2025
Jul 21 08:37:25 localhost kernel: Call Trace:
Jul 21 08:37:25 localhost kernel: <TASK>
Jul 21 08:37:25 localhost kernel: dump_stack_lvl+0x76/0xa0
Jul 21 08:37:25 localhost kernel: dump_stack+0x10/0x20
Jul 21 08:37:25 localhost kernel: __ubsan_handle_shift_out_of_bounds+0x1a5/0x380
Jul 21 08:37:25 localhost kernel: skx_get_dimm_info.cold+0x2a/0x17f [skx_edac_common]
Jul 21 08:37:25 localhost kernel: i10nm_get_dimm_config+0x1f9/0x300 [i10nm_edac]
Jul 21 08:37:25 localhost kernel: skx_register_mci+0x139/0x1e0 [skx_edac_common]
Jul 21 08:37:25 localhost kernel: ? __pfx_i10nm_get_dimm_config+0x10/0x10 [i10nm_edac]
Jul 21 08:37:25 localhost kernel: i10nm_init+0x42b/0xff0 [i10nm_edac]
Jul 21 08:37:25 localhost kernel: ? __pfx_i10nm_init+0x10/0x10 [i10nm_edac]

[Fix]
In linux-next
2e6fe1bbefd9 EDAC/i10nm: Skip DIMM enumeration on a disabled memory controller

Intel provides a fix for this issue
https://lore.kernel.org/lkml/20250806065707.3533345-1-qiuxu.zhuo@intel.com/

[Test]
Boot up the Intel Granite Rapids and check dmesg log, there should be no UBSAN shift-out-of-bounds message.

[Where problems could occur]
It adds extra check for edac i10nm driver, the impact should be low.

Qiuxu Zhuo (1):
  EDAC/i10nm: Skip DIMM enumeration on a disabled memory controller

 drivers/edac/i10nm_base.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

-- 
2.43.0