[PATCH 3/6] EDAC: fsl: Fix bad bit shift operations
From: Frank Li <Frank.Li@nxp.com>
Date: 2024-07-09 20:23:45
Also in:
imx, linux-devicetree, linux-edac, lkml
Subsystem:
edac-core, edac-fsl_ddr, the rest · Maintainers:
Borislav Petkov, Tony Luck, Linus Torvalds
From: Priyanka Singh <redacted>
The original code:
cap_high ^ (1 << (bad_data_bit - 32))
The variable bad_data_bit ranges from 0 to 63. If bad_data_bit is below 32,
bad_data_bit - 32 will be a negative value. Left shifting a negative
value in C is undefined behavior.
Fix this by checking the range of bad_data_bit.
Fixes: ea2eb9a8b620 ("EDAC, fsl-ddr: Separate FSL DDR driver from MPC85xx")
Signed-off-by: Priyanka Singh <redacted>
Reviewed-by: Sherry Sun <redacted>
Signed-off-by: Li Yang <redacted>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
drivers/edac/fsl_ddr_edac.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/edac/fsl_ddr_edac.c b/drivers/edac/fsl_ddr_edac.c
index 10b0a46669f3d..da743cf8a95e9 100644
--- a/drivers/edac/fsl_ddr_edac.c
+++ b/drivers/edac/fsl_ddr_edac.c@@ -338,11 +338,18 @@ static void fsl_mc_check(struct mem_ctl_info *mci) fsl_mc_printk(mci, KERN_ERR, "Faulty ECC bit: %d\n", bad_ecc_bit); - fsl_mc_printk(mci, KERN_ERR, - "Expected Data / ECC:\t%#8.8x_%08x / %#2.2x\n", - cap_high ^ (1 << (bad_data_bit - 32)), - cap_low ^ (1 << bad_data_bit), - syndrome ^ (1 << bad_ecc_bit)); + if ((bad_data_bit > 0 && bad_data_bit < 32) && bad_ecc_bit > 0) { + fsl_mc_printk(mci, KERN_ERR, + "Expected Data / ECC:\t%#8.8x_%08x / %#2.2x\n", + cap_high, cap_low ^ (1 << bad_data_bit), + syndrome ^ (1 << bad_ecc_bit)); + } + if (bad_data_bit >= 32 && bad_ecc_bit > 0) { + fsl_mc_printk(mci, KERN_ERR, + "Expected Data / ECC:\t%#8.8x_%08x / %#2.2x\n", + cap_high ^ (1 << (bad_data_bit - 32)), + cap_low, syndrome ^ (1 << bad_ecc_bit)); + } } fsl_mc_printk(mci, KERN_ERR,
--
2.34.1