flags_show() build their output with a seq_buf and return seq_buf_used(), which may include the trailing NUL byte when the seq_buf has overflowed. Use seq_buf_strlen() instead.
The flag names are far shorter than the PAGE_SIZE buffer sysfs provides, so this cannot overflow today. Build tested ARCH=x86_64 with GCC 16.2.0, built out of tree with make M=tools/testing/nvdimm: tools/testing/nvdimm/test/ndtest.o Assisted-by: LLM Reviewed-by: Andy Shevchenko <[email protected]> Reviewed-by: Dave Jiang <[email protected]> Signed-off-by: Kees Cook <[email protected]> --- Cc: <[email protected]> Cc: Alison Schofield <[email protected]> Cc: Dave Jiang <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Guangshuo Li <[email protected]> Cc: Ira Weiny <[email protected]> Cc: Uwe Kleine-König <[email protected]> Cc: Vishal Verma <[email protected]> --- tools/testing/nvdimm/test/ndtest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/nvdimm/test/ndtest.c b/tools/testing/nvdimm/test/ndtest.c index 2051ad5d4882..f097f2992966 100644 --- a/tools/testing/nvdimm/test/ndtest.c +++ b/tools/testing/nvdimm/test/ndtest.c @@ -693,7 +693,7 @@ static ssize_t flags_show(struct device *dev, if (seq_buf_used(&s)) seq_buf_printf(&s, "\n"); - return seq_buf_used(&s); + return seq_buf_strlen(&s); } static DEVICE_ATTR_RO(flags); -- 2.34.1
