Commit 789ef3db authored by Mark Brown's avatar Mark Brown Committed by Greg Kroah-Hartman

regmap: debugfs: Ensure we don't underflow when printing access masks

commit b763ec17ac762470eec5be8ebcc43e4f8b2c2b82 upstream.

If a read is attempted which is smaller than the line length then we may
underflow the subtraction we're doing with the unsigned size_t type so
move some of the calculation to be additions on the right hand side
instead in order to avoid this.
Reported-by: default avatarRasmus Villemoes <>
Signed-off-by: default avatarMark Brown <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 4d2c033d
......@@ -419,7 +419,7 @@ static ssize_t regmap_access_read_file(struct file *file,
/* If we're in the region the user is trying to read */
if (p >= *ppos) {
/* ...but not beyond it */
if (buf_pos >= count - 1 - tot_len)
if (buf_pos + tot_len + 1 >= count)
/* Format the register */
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