2022-10-20 15:18:01

by Petr Vorel

[permalink] [raw]
Subject: [PATCH 1/1] kernel/utsname_sysctl.c: Add missing enum uts_proc value

bfca3dd3d068 added new struct ctl_table uts_kern_table[], but not new
enum uts_proc value. It broke the notification mechanism between the
sethostname syscall and the pollers of /proc/sys/kernel/hostname.

The table uts_kern_table is addressed within uts_proc_notify by the enum
value, that's why new enum value is needed.

Fixes: bfca3dd3d068 ("kernel/utsname_sysctl.c: print kernel arch")

Reported-by: Torsten Hilbrich <[email protected]>
Signed-off-by: Petr Vorel <[email protected]>
---
Hi all,

I'm sorry to introduce a regression.

Torsten Hilbrich reported [1] that hostnamectl set-hostname foo
which does poll() got affected by bfca3dd3d068. He also wrote a
reproducer [2] which does not require systemd, I tested the patch on
dracut initramfs.

Kind regards,
Petr

[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://lore.kernel.org/lkml/[email protected]/2-hostname-poll-test.c

include/linux/utsname.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 2b1737c9b244..bf7613ba412b 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -10,6 +10,7 @@
#include <uapi/linux/utsname.h>

enum uts_proc {
+ UTS_PROC_ARCH,
UTS_PROC_OSTYPE,
UTS_PROC_OSRELEASE,
UTS_PROC_VERSION,
--
2.38.0


2022-10-20 15:18:25

by Petr Vorel

[permalink] [raw]
Subject: Re: [PATCH 1/1] kernel/utsname_sysctl.c: Add missing enum uts_proc value

Hi all,

[ Cc [email protected] ]

Kind regards,
Petr

> bfca3dd3d068 added new struct ctl_table uts_kern_table[], but not new
> enum uts_proc value. It broke the notification mechanism between the
> sethostname syscall and the pollers of /proc/sys/kernel/hostname.

> The table uts_kern_table is addressed within uts_proc_notify by the enum
> value, that's why new enum value is needed.

> Fixes: bfca3dd3d068 ("kernel/utsname_sysctl.c: print kernel arch")

> Reported-by: Torsten Hilbrich <[email protected]>
> Signed-off-by: Petr Vorel <[email protected]>
> ---
> Hi all,

> I'm sorry to introduce a regression.

> Torsten Hilbrich reported [1] that hostnamectl set-hostname foo
> which does poll() got affected by bfca3dd3d068. He also wrote a
> reproducer [2] which does not require systemd, I tested the patch on
> dracut initramfs.

> Kind regards,
> Petr

> [1] https://lore.kernel.org/lkml/[email protected]/
> [2] https://lore.kernel.org/lkml/[email protected]/2-hostname-poll-test.c

> include/linux/utsname.h | 1 +
> 1 file changed, 1 insertion(+)

> diff --git a/include/linux/utsname.h b/include/linux/utsname.h
> index 2b1737c9b244..bf7613ba412b 100644
> --- a/include/linux/utsname.h
> +++ b/include/linux/utsname.h
> @@ -10,6 +10,7 @@
> #include <uapi/linux/utsname.h>

> enum uts_proc {
> + UTS_PROC_ARCH,
> UTS_PROC_OSTYPE,
> UTS_PROC_OSRELEASE,
> UTS_PROC_VERSION,

2022-10-20 16:05:59

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH 1/1] kernel/utsname_sysctl.c: Add missing enum uts_proc value

On Thu, Oct 20, 2022 at 05:06:45PM +0200, Petr Vorel wrote:
> bfca3dd3d068 added new struct ctl_table uts_kern_table[], but not new
> enum uts_proc value. It broke the notification mechanism between the
> sethostname syscall and the pollers of /proc/sys/kernel/hostname.
>
> The table uts_kern_table is addressed within uts_proc_notify by the enum
> value, that's why new enum value is needed.
>
> Fixes: bfca3dd3d068 ("kernel/utsname_sysctl.c: print kernel arch")
>
> Reported-by: Torsten Hilbrich <[email protected]>
> Signed-off-by: Petr Vorel <[email protected]>
> ---
> Hi all,
>
> I'm sorry to introduce a regression.
>
> Torsten Hilbrich reported [1] that hostnamectl set-hostname foo
> which does poll() got affected by bfca3dd3d068. He also wrote a
> reproducer [2] which does not require systemd, I tested the patch on
> dracut initramfs.

Thanks for the quick response, I'll queue this up in my tree now.

greg k-h