2023-07-04 10:21:14

by Koba Ko

Subject: [PATCH v3] EDAC/i10nm: Fix an inappropriate shift exponent

A surprising value was determined after a read failure from a DIMM.

Software analyses pointed a data processing issue out.
`UBSAN: shift-out-of-bounds in drivers/edac/skx_common.c:369:16
shift exponent -66 is negative`

A special value combination could not be handled so far.

Check if an invalid value was detected by a call of the function “skx_get_dimm_attr”.
* Print a corresponding error message in this case.
* Return zero then directly from the function “skx_get_dimm_info”.

Fixes: 4ec656bdf43a ("EDAC, skx_edac: Add EDAC driver for Skylake")
Signed-off-by: Koba Ko <[email protected]>
---
v3: According to Markus' comments, simplify and polish the summary and add `Fixes:`
v2: make error-print explicitly

drivers/edac/skx_common.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/edac/skx_common.c b/drivers/edac/skx_common.c
index 2a00e0503f0d5..ac61db72d2e6b 100644
--- a/drivers/edac/skx_common.c
+++ b/drivers/edac/skx_common.c
@@ -330,7 +330,7 @@ static int skx_get_dimm_attr(u32 reg, int lobit, int hibit, int add,
u32 val = GET_BITFIELD(reg, lobit, hibit);

if (val < minval || val > maxval) {
- edac_dbg(2, "bad %s = %d (raw=0x%x)\n", name, val, reg);
+ skx_printk(KERN_ERR, "bad %s = %d (raw=0x%x)\n", name, val, reg);
return -EINVAL;
}
return val + add;
@@ -351,6 +351,8 @@ int skx_get_dimm_info(u32 mtr, u32 mcmtr, u32 amap, struct dimm_info *dimm,
ranks = numrank(mtr);
rows = numrow(mtr);
cols = imc->hbm_mc ? 6 : numcol(mtr);
+ if (ranks == -EINVAL || rows == -EINVAL || cols == -EINVAL)
+ return 0;

if (imc->hbm_mc) {
banks = 32;
--
2.25.1

2023-07-04 12:58:03

by Dan Carpenter

Subject: Re: [PATCH v3] EDAC/i10nm: Fix an inappropriate shift exponent

Good enough for me, thanks.

Reviewed-by: Dan Carpenter <[email protected]>

regards,
dan carpenter