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From: Chris Metcalf <cmetcalf@tilera.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	<linux-arch@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH] arch/tile: avoid calling do_signal() after fork from a kernel thread
Date: Sat, 28 Apr 2012 14:51:43 -0400	[thread overview]
Message-ID: <201204281858.q3SIwC7H014319@farm-0027.internal.tilera.com> (raw)
In-Reply-To: <20120427235023.GR6871@ZenIV.linux.org.uk>

Calling interrupt_return will check the privilege of the context we're
returning to avoid the possibility of kernel threads doing any kind
of userspace actions (including signal handling) after a fork.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
---
Al, thanks for noticing this.  I've queued it up for 3.4.

Do you have a case that might provoke the signal behavior in the
unpatched code?  The patched code passes our internal regressions.

 arch/tile/kernel/intvec_32.S |    2 +-
 arch/tile/kernel/intvec_64.S |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S
index 5d56a1e..d0f48ca 100644
--- a/arch/tile/kernel/intvec_32.S
+++ b/arch/tile/kernel/intvec_32.S
@@ -1274,7 +1274,7 @@ STD_ENTRY(ret_from_fork)
 	FEEDBACK_REENTER(ret_from_fork)
 	{
 	 movei  r30, 0               /* not an NMI */
-	 j      .Lresume_userspace   /* jump into middle of interrupt_return */
+	 j      interrupt_return
 	}
 	STD_ENDPROC(ret_from_fork)
 
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 49d9d66..252924b 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -1120,7 +1120,7 @@ STD_ENTRY(ret_from_fork)
 	FEEDBACK_REENTER(ret_from_fork)
 	{
 	 movei  r30, 0               /* not an NMI */
-	 j      .Lresume_userspace   /* jump into middle of interrupt_return */
+	 j      interrupt_return
 	}
 	STD_ENDPROC(ret_from_fork)
 
-- 
1.6.5.2


WARNING: multiple messages have this Message-ID (diff)
From: Chris Metcalf <cmetcalf@tilera.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] arch/tile: avoid calling do_signal() after fork from a kernel thread
Date: Sat, 28 Apr 2012 14:51:43 -0400	[thread overview]
Message-ID: <201204281858.q3SIwC7H014319@farm-0027.internal.tilera.com> (raw)
In-Reply-To: <20120427235023.GR6871@ZenIV.linux.org.uk>

Calling interrupt_return will check the privilege of the context we're
returning to avoid the possibility of kernel threads doing any kind
of userspace actions (including signal handling) after a fork.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
---
Al, thanks for noticing this.  I've queued it up for 3.4.

Do you have a case that might provoke the signal behavior in the
unpatched code?  The patched code passes our internal regressions.

 arch/tile/kernel/intvec_32.S |    2 +-
 arch/tile/kernel/intvec_64.S |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S
index 5d56a1e..d0f48ca 100644
--- a/arch/tile/kernel/intvec_32.S
+++ b/arch/tile/kernel/intvec_32.S
@@ -1274,7 +1274,7 @@ STD_ENTRY(ret_from_fork)
 	FEEDBACK_REENTER(ret_from_fork)
 	{
 	 movei  r30, 0               /* not an NMI */
-	 j      .Lresume_userspace   /* jump into middle of interrupt_return */
+	 j      interrupt_return
 	}
 	STD_ENDPROC(ret_from_fork)
 
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 49d9d66..252924b 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -1120,7 +1120,7 @@ STD_ENTRY(ret_from_fork)
 	FEEDBACK_REENTER(ret_from_fork)
 	{
 	 movei  r30, 0               /* not an NMI */
-	 j      .Lresume_userspace   /* jump into middle of interrupt_return */
+	 j      interrupt_return
 	}
 	STD_ENDPROC(ret_from_fork)
 
-- 
1.6.5.2

  reply	other threads:[~2012-04-28 19:13 UTC|newest]

Thread overview: 105+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-18 13:04 [PULL REQUEST] : ima-appraisal patches Mimi Zohar
2012-04-18 15:02 ` James Morris
2012-04-18 18:07   ` Mimi Zohar
2012-04-18 18:39     ` Al Viro
2012-04-18 20:56       ` Mimi Zohar
2012-04-19 19:57       ` Mimi Zohar
2012-04-20  0:43         ` [RFC] situation with fput() locking (was Re: [PULL REQUEST] : ima-appraisal patches) Al Viro
2012-04-20  2:31           ` Linus Torvalds
2012-04-20  2:31             ` Linus Torvalds
2012-04-20  2:54             ` Al Viro
2012-04-20  2:58               ` Linus Torvalds
2012-04-20  2:58                 ` Linus Torvalds
2012-04-20  8:09                 ` Al Viro
2012-04-20 15:56                   ` Linus Torvalds
2012-04-20 15:56                     ` Linus Torvalds
2012-04-20 16:08                     ` Al Viro
2012-04-20 16:42                       ` Al Viro
2012-04-20 17:21                         ` Linus Torvalds
2012-04-20 17:21                           ` Linus Torvalds
2012-04-20 18:07                           ` Al Viro
2012-04-23 18:01                             ` [RFC] TIF_NOTIFY_RESUME, arch/*/*/*signal*.c and all such Al Viro
2012-04-23 18:37                               ` Oleg Nesterov
2012-04-24  7:26                               ` Al Viro
2012-04-25  3:06                                 ` Al Viro
2012-04-25 12:37                                   ` Oleg Nesterov
2012-04-25 12:50                                     ` Al Viro
2012-04-25 13:03                                       ` Oleg Nesterov
2012-04-25 13:32                                         ` Oleg Nesterov
2012-04-25 13:32                                         ` Al Viro
2012-04-25 14:52                                           ` Oleg Nesterov
2012-04-25 15:46                                             ` Oleg Nesterov
2012-04-25 16:10                                               ` Al Viro
2012-04-25 17:02                                                 ` Oleg Nesterov
2012-04-25 17:51                                                   ` Al Viro
2012-04-26  7:15                                                     ` Martin Schwidefsky
2012-04-26  7:25                                                       ` David Miller
2012-04-26 13:52                                                       ` Oleg Nesterov
2012-04-26 14:31                                                         ` Martin Schwidefsky
2012-04-26 13:22                                                     ` Oleg Nesterov
2012-04-26 18:37                                 ` Oleg Nesterov
2012-04-26 23:19                                   ` Al Viro
2012-04-27 17:24                                     ` Oleg Nesterov
2012-04-27 17:54                                       ` Oleg Nesterov
2012-05-02 10:37                                         ` Matt Fleming
2012-05-02 14:14                                           ` Al Viro
2012-04-27 18:45                                       ` Al Viro
2012-04-27 19:14                                         ` Geert Uytterhoeven
2012-04-27 19:34                                           ` Al Viro
2012-04-29 22:51                                             ` Al Viro
2012-04-30  6:39                                               ` Greg Ungerer
2012-04-30  6:39                                                 ` Greg Ungerer
2012-04-27 19:42                                         ` Al Viro
2012-04-27 20:20                                         ` Roland McGrath
2012-04-27 21:12                                           ` Al Viro
2012-04-27 21:27                                             ` Roland McGrath
2012-04-27 23:15                                               ` Al Viro
2012-04-27 23:32                                                 ` Al Viro
2012-04-29  4:12                                                   ` Al Viro
2012-04-30  8:06                                                     ` Martin Schwidefsky
2012-04-27 23:50                                                 ` Al Viro
2012-04-28 18:51                                                   ` Chris Metcalf [this message]
2012-04-28 18:51                                                     ` [PATCH] arch/tile: avoid calling do_signal() after fork from a kernel thread Chris Metcalf
2012-04-28 20:55                                                     ` Al Viro
2012-04-28 21:46                                                       ` Chris Metcalf
2012-04-28 21:46                                                         ` Chris Metcalf
2012-04-29  0:55                                                         ` Al Viro
2012-04-28 18:51                                                           ` [PATCH v2] arch/tile: fix up some issues in calling do_work_pending() Chris Metcalf
2012-04-28 18:51                                                             ` Chris Metcalf
2012-04-29  3:49                                                           ` [PATCH] arch/tile: avoid calling do_signal() after fork from a kernel thread Chris Metcalf
2012-04-29  3:49                                                             ` Chris Metcalf
2012-04-28  2:42                                                 ` [RFC] TIF_NOTIFY_RESUME, arch/*/*/*signal*.c and all such Al Viro
2012-04-28  3:32                                                   ` Al Viro
2012-04-28  3:36                                                     ` Al Viro
2012-04-29 16:33                                                     ` Oleg Nesterov
2012-04-29 16:18                                                   ` Oleg Nesterov
2012-04-29 18:05                                                     ` Al Viro
2012-05-01  4:31                                                       ` Al Viro
2012-05-01  5:06                                                         ` Mike Frysinger
2012-05-01  5:52                                                           ` Al Viro
2012-05-02 17:24                                                             ` Al Viro
2012-05-02 18:30                                                       ` Oleg Nesterov
2012-04-29 16:41                                         ` Oleg Nesterov
2012-04-29 18:09                                           ` Al Viro
2012-04-29 18:25                                             ` Oleg Nesterov
2012-04-20  3:15               ` [RFC] situation with fput() locking (was Re: [PULL REQUEST] : ima-appraisal patches) Al Viro
2012-04-20 18:54           ` Hugh Dickins
2012-04-20 19:04             ` Al Viro
2012-04-20 19:18               ` Linus Torvalds
2012-04-20 19:32                 ` Hugh Dickins
2012-04-20 19:58                 ` Al Viro
2012-04-20 21:12                   ` Linus Torvalds
2012-04-20 21:12                     ` Linus Torvalds
2012-04-20 22:13                     ` Al Viro
2012-04-20 22:35                       ` Linus Torvalds
2012-04-20 22:35                         ` Linus Torvalds
2012-04-27  7:35                         ` Kasatkin, Dmitry
2012-04-27 17:34                           ` Al Viro
2012-04-27 18:52                             ` Kasatkin, Dmitry
2012-04-27 18:52                               ` Kasatkin, Dmitry
2012-04-27 19:15                               ` Kasatkin, Dmitry
2012-04-30 14:32                             ` Mimi Zohar
2012-04-30 14:32                               ` Mimi Zohar
2012-05-03  4:23                               ` James Morris
2012-05-03  4:23                                 ` James Morris
2012-04-20 19:37               ` Al Viro

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