From c1bef05763c94ae284ee2881c03bf0753f8d213a Mon Sep 17 00:00:00 2001 From: Xu Rao Date: Mon, 8 Jun 2026 14:31:47 +0800 Subject: [PATCH] thunderbolt: debugfs: Fix sideband write size check sb_regs_write() looks up the matching sideband register entry before validating the number of bytes to write. However, the size check uses sb_regs->size, which is the size of the first entry in the register table, instead of the matched entry. This rejects valid writes to larger sideband registers such as USB4_SB_DEBUG or USB4_SB_DATA. Use the matched register entry for the size check. Signed-off-by: Xu Rao Signed-off-by: Mika Westerberg --- drivers/thunderbolt/debugfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c index 369904287497..f5cf0e177f40 100644 --- a/drivers/thunderbolt/debugfs.c +++ b/drivers/thunderbolt/debugfs.c @@ -366,7 +366,7 @@ static ssize_t sb_regs_write(struct tb_port *port, const struct sb_reg *sb_regs, if (!sb_reg) return -EINVAL; - if (bytes_read > sb_regs->size) + if (bytes_read > sb_reg->size) return -E2BIG; ret = usb4_port_sb_write(port, target, index, sb_reg->reg, data,