From: "Theodore Ts'o" <tytso@mit.edu>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Walt Drummond <walt@drummond.us>,
aacraid@microsemi.com, viro@zeniv.linux.org.uk,
anna.schumaker@netapp.com, arnd@arndb.de, bsegall@google.com,
bp@alien8.de, chuck.lever@oracle.com, bristot@redhat.com,
dave.hansen@linux.intel.com, dwmw2@infradead.org,
dietmar.eggemann@arm.com, dinguyen@kernel.org,
geert@linux-m68k.org, gregkh@linuxfoundation.org, hpa@zytor.com,
idryomov@gmail.com, mingo@redhat.com, yzaikin@google.com,
ink@jurassic.park.msu.ru, jejb@linux.ibm.com, jmorris@namei.org,
bfields@fieldses.org, jlayton@kernel.org, jirislaby@kernel.org,
john.johansen@canonical.com, juri.lelli@redhat.com,
keescook@chromium.org, mcgrof@kernel.org,
martin.petersen@oracle.com, mattst88@gmail.com, mgorman@suse.de,
oleg@redhat.com, pbonzini@redhat.com, peterz@infradead.org,
rth@twiddle.net, richard@nod.at, serge@hallyn.com,
rostedt@goodmis.org, tglx@linutronix.de,
trond.myklebust@hammerspace.com, vincent.guittot@linaro.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
ceph-devel@vger.kernel.org, kvm@vger.kernel.org,
linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-m68k@vger.kernel.org,
linux-mtd@lists.infradead.org, linux-nfs@vger.kernel.org,
linux-scsi@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [RFC PATCH 0/8] signals: Support more than 64 signals
Date: Tue, 4 Jan 2022 17:23:19 -0500 [thread overview]
Message-ID: <YdTI16ZxFFNco7rH@mit.edu> (raw)
In-Reply-To: <87pmp79mxl.fsf@email.froward.int.ebiederm.org>
On Tue, Jan 04, 2022 at 04:05:26PM -0600, Eric W. Biederman wrote:
>
> That is all as expected, and does not demonstrate a regression would
> happen if SIGPWR were to treat SIG_DFL as SIG_IGN, as SIGWINCH, SIGCONT,
> SIGCHLD, SIGURG do. It does show there is the possibility of problems.
>
> The practical question is does anything send SIGPWR to anything besides
> init, and expect the process to handle SIGPWR or terminate?
So if I *cared* about SIGINFO, what I'd do is ask the systemd
developers and users list if there are any users of the sigpwr.target
feature that they know of. And I'd also download all of the open
source UPS monitoring applications (and perhaps documentation of
closed-source UPS applications, such as for example APC's program) and
see if any of them are trying to send the SIGPWR signal.
I don't personally think it's worth the effort to do that research,
but maybe other people care enough to do the work.
> > I claim, though, that we could implement VSTATUS without implenting
> > the SIGINFO part of the feature.
>
> I agree that is the place to start. And if we aren't going to use
> SIGINFO perhaps we could have an equally good notification method
> if anyone wants one. Say call an ioctl and get an fd that can
> be read when a VSTATUS request comes in.
>
> SIGINFO vs SIGCONT vs a fd vs something else is something we can sort
> out when people get interested in modifying userspace.
Once VSTATUS support lands in the kernel, we can wait and see if there
is anyone who shows up wanting the SIGINFO functionality. Certainly
we have no shortage of userspace notification interfaces in Linux. :-)
- Ted
WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Walt Drummond <walt@drummond.us>,
aacraid@microsemi.com, viro@zeniv.linux.org.uk,
anna.schumaker@netapp.com, arnd@arndb.de, bsegall@google.com,
bp@alien8.de, chuck.lever@oracle.com, bristot@redhat.com,
dave.hansen@linux.intel.com, dwmw2@infradead.org,
dietmar.eggemann@arm.com, dinguyen@kernel.org,
geert@linux-m68k.org, gregkh@linuxfoundation.org, hpa@zytor.com,
idryomov@gmail.com, mingo@redhat.com, yzaikin@google.com,
ink@jurassic.park.msu.ru, jejb@linux.ibm.com, jmorris@namei.org,
bfields@fieldses.org, jlayton@kernel.org, jirislaby@kernel.org,
john.johansen@canonical.com, juri.lelli@redhat.com,
keescook@chromium.org, mcgrof@kernel.org,
martin.petersen@oracle.com, mattst88@gmail.com, mgorman@suse.de,
oleg@redhat.com, pbonzini@redhat.com, peterz@infradead.org,
rth@twiddle.net, richard@nod.at, serge@hallyn.com,
rostedt@goodmis.org, tglx@linutronix.de,
trond.myklebust@hammerspace.com, vincent.guittot@linaro.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
ceph-devel@vger.kernel.org, kvm@vger.kernel.org,
linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-m68k@vger.kernel.org,
linux-mtd@lists.infradead.org, linux-nfs@vger.kernel.org,
linux-scsi@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [RFC PATCH 0/8] signals: Support more than 64 signals
Date: Tue, 4 Jan 2022 17:23:19 -0500 [thread overview]
Message-ID: <YdTI16ZxFFNco7rH@mit.edu> (raw)
In-Reply-To: <87pmp79mxl.fsf@email.froward.int.ebiederm.org>
On Tue, Jan 04, 2022 at 04:05:26PM -0600, Eric W. Biederman wrote:
>
> That is all as expected, and does not demonstrate a regression would
> happen if SIGPWR were to treat SIG_DFL as SIG_IGN, as SIGWINCH, SIGCONT,
> SIGCHLD, SIGURG do. It does show there is the possibility of problems.
>
> The practical question is does anything send SIGPWR to anything besides
> init, and expect the process to handle SIGPWR or terminate?
So if I *cared* about SIGINFO, what I'd do is ask the systemd
developers and users list if there are any users of the sigpwr.target
feature that they know of. And I'd also download all of the open
source UPS monitoring applications (and perhaps documentation of
closed-source UPS applications, such as for example APC's program) and
see if any of them are trying to send the SIGPWR signal.
I don't personally think it's worth the effort to do that research,
but maybe other people care enough to do the work.
> > I claim, though, that we could implement VSTATUS without implenting
> > the SIGINFO part of the feature.
>
> I agree that is the place to start. And if we aren't going to use
> SIGINFO perhaps we could have an equally good notification method
> if anyone wants one. Say call an ioctl and get an fd that can
> be read when a VSTATUS request comes in.
>
> SIGINFO vs SIGCONT vs a fd vs something else is something we can sort
> out when people get interested in modifying userspace.
Once VSTATUS support lands in the kernel, we can wait and see if there
is anyone who shows up wanting the SIGINFO functionality. Certainly
we have no shortage of userspace notification interfaces in Linux. :-)
- Ted
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Walt Drummond <walt@drummond.us>,
aacraid@microsemi.com, viro@zeniv.linux.org.uk,
anna.schumaker@netapp.com, arnd@arndb.de, bsegall@google.com,
bp@alien8.de, chuck.lever@oracle.com, bristot@redhat.com,
dave.hansen@linux.intel.com, dwmw2@infradead.org,
dietmar.eggemann@arm.com, dinguyen@kernel.org,
geert@linux-m68k.org, gregkh@linuxfoundation.org, hpa@zytor.com,
idryomov@gmail.com, mingo@redhat.com, yzaikin@google.com,
ink@jurassic.park.msu.ru, jejb@linux.ibm.com, jmorris@namei.org,
bfields@fieldses.org, jlayton@kernel.org, jirislaby@kernel.org,
john.johansen@canonical.com, juri.lelli@redhat.com,
keescook@chromium.org, mcgrof@kernel.org,
martin.petersen@oracle.com, mattst88@gmail.com, mgorman@suse.de,
oleg@redhat.com, pbonzini@redhat.com, peterz@infradead.org,
rth@twiddle.net, richa
Subject: Re: [RFC PATCH 0/8] signals: Support more than 64 signals
Date: Tue, 4 Jan 2022 17:23:19 -0500 [thread overview]
Message-ID: <YdTI16ZxFFNco7rH@mit.edu> (raw)
In-Reply-To: <87pmp79mxl.fsf@email.froward.int.ebiederm.org>
On Tue, Jan 04, 2022 at 04:05:26PM -0600, Eric W. Biederman wrote:
>
> That is all as expected, and does not demonstrate a regression would
> happen if SIGPWR were to treat SIG_DFL as SIG_IGN, as SIGWINCH, SIGCONT,
> SIGCHLD, SIGURG do. It does show there is the possibility of problems.
>
> The practical question is does anything send SIGPWR to anything besides
> init, and expect the process to handle SIGPWR or terminate?
So if I *cared* about SIGINFO, what I'd do is ask the systemd
developers and users list if there are any users of the sigpwr.target
feature that they know of. And I'd also download all of the open
source UPS monitoring applications (and perhaps documentation of
closed-source UPS applications, such as for example APC's program) and
see if any of them are trying to send the SIGPWR signal.
I don't personally think it's worth the effort to do that research,
but maybe other people care enough to do the work.
> > I claim, though, that we could implement VSTATUS without implenting
> > the SIGINFO part of the feature.
>
> I agree that is the place to start. And if we aren't going to use
> SIGINFO perhaps we could have an equally good notification method
> if anyone wants one. Say call an ioctl and get an fd that can
> be read when a VSTATUS request comes in.
>
> SIGINFO vs SIGCONT vs a fd vs something else is something we can sort
> out when people get interested in modifying userspace.
Once VSTATUS support lands in the kernel, we can wait and see if there
is anyone who shows up wanting the SIGINFO functionality. Certainly
we have no shortage of userspace notification interfaces in Linux. :-)
- Ted
next prev parent reply other threads:[~2022-01-04 22:24 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-03 18:19 [RFC PATCH 0/8] signals: Support more than 64 signals Walt Drummond
2022-01-03 18:19 ` Walt Drummond
2022-01-03 18:19 ` Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 1/8] signals: Make the real-time signal system calls accept different sized sigset_t from user space Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 2/8] signals: Put the full signal mask on the signal stack for x86_64, X32 and ia32 compatibility mode Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 3/8] signals: Use a helper function to test if a signal is a real-time signal Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 4/8] signals: Remove sigmask() macro Walt Drummond
2022-01-03 18:19 ` Walt Drummond
2022-01-03 18:19 ` Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 5/8] signals: Better support cases where _NSIG_WORDS is greater than 2 Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 6/8] signals: Round up _NSIG_WORDS Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 7/8] signals: Add signal debugging Walt Drummond
2022-01-03 18:19 ` [RFC PATCH 8/8] signals: Support BSD VSTATUS, KERNINFO and SIGINFO Walt Drummond
2022-01-04 7:27 ` Greg Kroah-Hartman
2022-01-07 21:48 ` Arseny Maslennikov
2022-01-07 21:52 ` Walt Drummond
2022-01-07 22:39 ` Arseny Maslennikov
2022-01-08 14:38 ` Arseny Maslennikov
2022-01-03 18:48 ` [RFC PATCH 0/8] signals: Support more than 64 signals Al Viro
2022-01-03 18:48 ` Al Viro
2022-01-03 18:48 ` Al Viro
2022-01-04 1:00 ` Walt Drummond
2022-01-04 1:00 ` Walt Drummond
2022-01-04 1:00 ` Walt Drummond
2022-01-04 1:16 ` Al Viro
2022-01-04 1:16 ` Al Viro
2022-01-04 1:16 ` Al Viro
2022-01-04 1:49 ` Al Viro
2022-01-04 1:49 ` Al Viro
2022-01-04 1:49 ` Al Viro
2022-01-04 18:00 ` Eric W. Biederman
2022-01-04 18:00 ` Eric W. Biederman
2022-01-04 18:00 ` Eric W. Biederman
2022-01-04 20:52 ` Theodore Ts'o
2022-01-04 20:52 ` Theodore Ts'o
2022-01-04 20:52 ` Theodore Ts'o
2022-01-04 21:33 ` Walt Drummond
2022-01-04 21:33 ` Walt Drummond
2022-01-04 21:33 ` Walt Drummond
2022-01-04 22:05 ` Eric W. Biederman
2022-01-04 22:05 ` Eric W. Biederman
2022-01-04 22:05 ` Eric W. Biederman
2022-01-04 22:23 ` Theodore Ts'o [this message]
2022-01-04 22:23 ` Theodore Ts'o
2022-01-04 22:23 ` Theodore Ts'o
2022-01-04 22:31 ` Walt Drummond
2022-01-04 22:31 ` Walt Drummond
2022-01-04 22:31 ` Walt Drummond
2022-01-07 19:29 ` Arseny Maslennikov
2022-01-07 19:29 ` Arseny Maslennikov
2022-01-07 19:29 ` Arseny Maslennikov
2022-05-19 12:27 ` Pavel Machek
2022-05-19 12:27 ` Pavel Machek
2022-05-19 12:27 ` Pavel Machek
2022-01-07 19:19 ` Arseny Maslennikov
2022-01-07 19:19 ` Arseny Maslennikov
2022-01-07 19:19 ` Arseny Maslennikov
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