2024-01-08 10:32:45

by Petre Rodan

Subject: [PATCH 1/1] tools: iio: replace seekdir() in iio_generic_buffer

Replace seekdir() with rewinddir() in order to fix a localized glibc bug.

One of the glibc patches that stable Gentoo is using causes an improper
directory stream positioning bug on 32bit arm. That in turn ends up as a
floating point exception in iio_generic_buffer.

The attached patch provides a fix by using an equivalent function which
should not cause trouble for other distros.

https://sourceware.org/bugzilla/show_bug.cgi?id=31212

Signed-off-by: Petre Rodan <[email protected]>
---
tools/iio/iio_utils.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
index 6a00a6eecaef..c5c5082cb24e 100644
--- a/tools/iio/iio_utils.c
+++ b/tools/iio/iio_utils.c
@@ -376,7 +376,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
goto error_close_dir;
}

- seekdir(dp, 0);
+ rewinddir(dp);
while (ent = readdir(dp), ent) {
if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
"_en") == 0) {
--
2.41.0

2024-01-13 15:19:43

by Jonathan Cameron

Subject: Re: [PATCH 1/1] tools: iio: replace seekdir() in iio_generic_buffer

On Mon, 8 Jan 2024 12:32:20 +0200
Petre Rodan <[email protected]> wrote:

> Replace seekdir() with rewinddir() in order to fix a localized glibc bug.
>
> One of the glibc patches that stable Gentoo is using causes an improper
> directory stream positioning bug on 32bit arm. That in turn ends up as a
> floating point exception in iio_generic_buffer.
>
> The attached patch provides a fix by using an equivalent function which
> should not cause trouble for other distros.
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=31212
>
> Signed-off-by: Petre Rodan <[email protected]>
I tweaked the description a tiny bit to say it's also easier to reason about
in general.

Applied to the togreg branch of iio.git and pushed out as tesing for 0-day
to probably ignore it.

Thanks,

Jonathan

> ---
> tools/iio/iio_utils.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
> index 6a00a6eecaef..c5c5082cb24e 100644
> --- a/tools/iio/iio_utils.c
> +++ b/tools/iio/iio_utils.c
> @@ -376,7 +376,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
> goto error_close_dir;
> }
>
> - seekdir(dp, 0);
> + rewinddir(dp);
> while (ent = readdir(dp), ent) {
> if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
> "_en") == 0) {
> --
> 2.41.0
>