From: Linus Torvalds <torvalds@linux-foundation.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Deepa Dinamani <deepa.kernel@gmail.com>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Davidlohr Bueso <dbueso@suse.de>,
Jens Axboe <axboe@kernel.dk>, Davidlohr Bueso <dave@stgolabs.net>,
e@80x24.org, Jason Baron <jbaron@akamai.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-aio@kvack.org, omar.kilani@gmail.com,
Thomas Gleixner <tglx@linutronix.de>,
stable <stable@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
"Eric W. Biederman" <ebiederm@xmission.com>,
David Laight <David.Laight@aculab.com>
Subject: Re: [PATCH -mm 0/1] signal: simplify set_user_sigmask/restore_user_sigmask
Date: Wed, 5 Jun 2019 10:24:47 -0700 [thread overview]
Message-ID: <CAHk-=wjkNx8u4Mcm5dfSQKYQmLQAv1Z1yGLDZvty7BVSj4eqBA@mail.gmail.com> (raw)
In-Reply-To: <20190605155801.GA25165@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 695 bytes --]
On Wed, Jun 5, 2019 at 8:58 AM Oleg Nesterov <oleg@redhat.com> wrote:
>
> To simplify the review, please see the code with this patch applied.
> I am using epoll_pwait() as an example because it looks very simple.
I like it.
However.
I think I'd like it even more if we just said "we don't need
restore_saved_sigmask AT ALL".
Which would be fairly easy to do with something like the attached...
(Yes, this only does x86, which is a problem, but I'm bringing this up
as a RFC..)
Is it worth another TIF flag? This sure would simplify things, and it
really fits the concept too: this really is a do_signal() issue, and
fundamentally goes together with TIF_SIGPENDING.
Linus
[-- Attachment #2: patch.diff --]
[-- Type: text/x-patch, Size: 2079 bytes --]
arch/x86/entry/common.c | 2 +-
arch/x86/include/asm/thread_info.h | 2 ++
kernel/signal.c | 1 +
3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index a986b3c8294c..eb538ecd6603 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -160,7 +160,7 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
klp_update_patch_state(current);
/* deal with pending signal delivery */
- if (cached_flags & _TIF_SIGPENDING)
+ if (cached_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal(regs);
if (cached_flags & _TIF_NOTIFY_RESUME) {
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index f9453536f9bb..d77a9f841455 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -92,6 +92,7 @@ struct thread_info {
#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* IA32 compatibility process */
+#define TIF_RESTORE_SIGMASK 18 /* Restore saved sigmask on return to user space */
#define TIF_NOHZ 19 /* in adaptive nohz mode */
#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
@@ -122,6 +123,7 @@ struct thread_info {
#define _TIF_NOCPUID (1 << TIF_NOCPUID)
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
+#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_NOHZ (1 << TIF_NOHZ)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
diff --git a/kernel/signal.c b/kernel/signal.c
index 328a01e1a2f0..a3346da1a4f5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2877,6 +2877,7 @@ int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
*oldset = current->blocked;
set_current_blocked(set);
+ set_thread_flag(TIF_RESTORE_SIGMASK);
return 0;
}
next prev parent reply other threads:[~2019-06-05 17:33 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-22 3:21 [PATCH v2] signal: Adjust error codes according to restore_user_sigmask() Deepa Dinamani
2019-05-22 15:05 ` Oleg Nesterov
2019-05-22 15:55 ` Deepa Dinamani
2019-05-22 16:14 ` Oleg Nesterov
2019-05-22 16:33 ` Deepa Dinamani
2019-05-23 9:03 ` David Laight
2019-05-23 14:59 ` Oleg Nesterov
2019-05-23 16:18 ` David Laight
2019-05-23 16:36 ` Oleg Nesterov
2019-05-23 16:56 ` David Laight
2019-05-23 18:06 ` Deepa Dinamani
2019-05-23 20:41 ` Deepa Dinamani
2019-05-23 21:06 ` Deepa Dinamani
2019-05-24 9:58 ` David Laight
2019-05-24 14:10 ` Oleg Nesterov
2019-05-24 15:16 ` Deepa Dinamani
2019-05-24 16:33 ` Oleg Nesterov
2019-05-24 17:01 ` Deepa Dinamani
2019-05-27 15:04 ` Oleg Nesterov
2019-05-28 20:47 ` Deepa Dinamani
2019-05-29 16:57 ` Oleg Nesterov
2019-05-29 18:42 ` Deepa Dinamani
2019-05-28 9:02 ` David Laight
2019-05-28 9:12 ` David Laight
2019-05-28 11:37 ` Deepa Dinamani
2019-05-28 12:04 ` David Laight
2019-05-24 14:19 ` Oleg Nesterov
2019-05-24 14:29 ` Deepa Dinamani
2019-05-24 14:51 ` Oleg Nesterov
2019-05-24 13:29 ` Oleg Nesterov
2019-05-24 14:59 ` David Laight
2019-05-24 15:09 ` David Laight
2019-05-24 15:46 ` Oleg Nesterov
2019-05-24 15:44 ` Oleg Nesterov
2019-05-24 16:40 ` David Laight
2019-05-23 14:33 ` Oleg Nesterov
2019-05-22 22:18 ` Chris Down
2019-05-22 22:52 ` Deepa Dinamani
2019-05-29 16:11 ` pselect/etc semantics (Was: [PATCH v2] signal: Adjust error codes according to restore_user_sigmask()) Oleg Nesterov
2019-05-29 16:54 ` David Laight
2019-05-29 18:50 ` Eric Wong
2019-05-30 9:34 ` David Laight
2019-05-30 13:04 ` pselect/etc semantics Eric W. Biederman
2019-05-29 16:56 ` pselect/etc semantics (Was: [PATCH v2] signal: Adjust error codes according to restore_user_sigmask()) Deepa Dinamani
2019-05-29 18:26 ` Deepa Dinamani
2019-05-29 22:32 ` Arnd Bergmann
2019-05-30 1:54 ` pselect/etc semantics Eric W. Biederman
2019-05-30 18:28 ` Arnd Bergmann
2019-05-30 14:40 ` pselect/etc semantics (Was: [PATCH v2] signal: Adjust error codes according to restore_user_sigmask()) Oleg Nesterov
2019-05-30 18:37 ` Arnd Bergmann
2019-05-30 13:01 ` pselect/etc semantics Eric W. Biederman
2019-05-30 15:18 ` David Laight
2019-05-30 16:13 ` Oleg Nesterov
2019-05-30 15:38 ` Eric W. Biederman
2019-05-30 15:48 ` Deepa Dinamani
2019-05-30 16:59 ` Deepa Dinamani
2019-05-30 16:08 ` Oleg Nesterov
2019-05-30 17:20 ` Eric W. Biederman
2019-05-30 16:22 ` David Laight
2019-05-30 15:57 ` Oleg Nesterov
2019-05-30 21:03 ` Eric Wong
2019-06-04 13:41 ` [PATCH] signal: remove the wrong signal_pending() check in restore_user_sigmask() Oleg Nesterov
2019-06-04 15:31 ` Eric W. Biederman
2019-06-04 15:57 ` David Laight
2019-06-04 16:37 ` Arnd Bergmann
2019-06-04 18:14 ` Deepa Dinamani
2019-06-04 18:35 ` Eric Wong
2019-06-04 21:26 ` Linus Torvalds
2019-06-04 22:24 ` Eric Wong
2019-06-04 23:51 ` Eric W. Biederman
2019-06-05 9:04 ` Oleg Nesterov
2019-06-05 8:56 ` Oleg Nesterov
2019-06-05 9:02 ` David Laight
2019-06-05 9:25 ` Oleg Nesterov
2019-06-05 9:58 ` David Laight
2019-06-05 15:58 ` [PATCH -mm 0/1] signal: simplify set_user_sigmask/restore_user_sigmask Oleg Nesterov
2019-06-05 15:58 ` [PATCH -mm 1/1] " Oleg Nesterov
2019-06-06 0:14 ` kbuild test robot
2019-06-06 1:06 ` kbuild test robot
2019-06-06 7:25 ` Oleg Nesterov
2019-06-06 7:30 ` Sedat Dilek
2019-06-05 17:24 ` Linus Torvalds [this message]
2019-06-06 9:05 ` [PATCH -mm 0/1] " David Laight
2019-06-06 11:05 ` Oleg Nesterov
2019-06-06 11:29 ` David Laight
2019-06-06 12:41 ` Oleg Nesterov
2019-06-06 13:23 ` David Laight
2019-06-06 10:22 ` Oleg Nesterov
2019-06-06 11:32 ` [PATCH -mm V2 1/1] " Oleg Nesterov
2019-06-06 14:08 ` [PATCH 0/2] select: simplify the usage of restore_saved_sigmask_unless() Oleg Nesterov
2019-06-06 14:08 ` [PATCH 1/2] select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR Oleg Nesterov
2019-06-07 18:05 ` Linus Torvalds
2019-06-06 14:09 ` [PATCH 2/2] select: shift restore_saved_sigmask_unless() into poll_select_copy_remaining() Oleg Nesterov
2019-06-07 21:39 ` [RFC PATCH 0/5]: Removing saved_sigmask Eric W. Biederman
2019-06-11 18:58 ` Oleg Nesterov
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