linux-kernel - [PATCH 3.10 62/70] mm: invoke oom-killer from remaining unconverted page fault handlers

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Date:	Wed, 19 Nov 2014 12:52:53 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...e.cz>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	David Rientjes <rientjes@...gle.com>,
	James Hogan <james.hogan@...tec.com>,
	David Howells <dhowells@...hat.com>,
	Jonas Bonn <jonas@...thpole.se>,
	Chen Liqin <liqin.chen@...plusct.com>,
	Lennox Wu <lennox.wu@...il.com>,
	Chris Metcalf <cmetcalf@...era.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Cong Wang <xiyou.wangcong@...il.com>
Subject: [PATCH 3.10 62/70] mm: invoke oom-killer from remaining unconverted page fault handlers

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Weiner <hannes@...xchg.org>

commit 609838cfed972d49a65aac7923a9ff5cbe482e30 upstream.

A few remaining architectures directly kill the page faulting task in an
out of memory situation.  This is usually not a good idea since that
task might not even use a significant amount of memory and so may not be
the optimal victim to resolve the situation.

Since 2.6.29's 1c0fe6e ("mm: invoke oom-killer from page fault") there
is a hook that architecture page fault handlers are supposed to call to
invoke the OOM killer and let it pick the right task to kill.  Convert
the remaining architectures over to this hook.

To have the previous behavior of simply taking out the faulting task the
vm.oom_kill_allocating_task sysctl can be set to 1.

Signed-off-by: Johannes Weiner <hannes@...xchg.org>
Reviewed-by: Michal Hocko <mhocko@...e.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Acked-by: David Rientjes <rientjes@...gle.com>
Acked-by: Vineet Gupta <vgupta@...opsys.com>   [arch/arc bits]
Cc: James Hogan <james.hogan@...tec.com>
Cc: David Howells <dhowells@...hat.com>
Cc: Jonas Bonn <jonas@...thpole.se>
Cc: Chen Liqin <liqin.chen@...plusct.com>
Cc: Lennox Wu <lennox.wu@...il.com>
Cc: Chris Metcalf <cmetcalf@...era.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arc/mm/fault.c      |    6 ++++--
 arch/metag/mm/fault.c    |    6 ++++--
 arch/mn10300/mm/fault.c  |    7 ++++---
 arch/openrisc/mm/fault.c |    8 ++++----
 arch/score/mm/fault.c    |    8 ++++----
 arch/tile/mm/fault.c     |    8 ++++----
 6 files changed, 24 insertions(+), 19 deletions(-)

--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -206,8 +206,10 @@ out_of_memory:
 	}
 	up_read(&mm->mmap_sem);
 
-	if (user_mode(regs))
-		do_group_exit(SIGKILL);	/* This will never return */
+	if (user_mode(regs)) {
+		pagefault_out_of_memory();
+		return;
+	}
 
 	goto no_context;
 
--- a/arch/metag/mm/fault.c
+++ b/arch/metag/mm/fault.c
@@ -224,8 +224,10 @@ do_sigbus:
 	 */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (user_mode(regs))
-		do_group_exit(SIGKILL);
+	if (user_mode(regs)) {
+		pagefault_out_of_memory();
+		return 1;
+	}
 
 no_context:
 	/* Are we prepared to handle this kernel fault?  */
--- a/arch/mn10300/mm/fault.c
+++ b/arch/mn10300/mm/fault.c
@@ -345,9 +345,10 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	printk(KERN_ALERT "VM: killing process %s\n", tsk->comm);
-	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
-		do_exit(SIGKILL);
+	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
+		pagefault_out_of_memory();
+		return;
+	}
 	goto no_context;
 
 do_sigbus:
--- a/arch/openrisc/mm/fault.c
+++ b/arch/openrisc/mm/fault.c
@@ -267,10 +267,10 @@ out_of_memory:
 	__asm__ __volatile__("l.nop 1");
 
 	up_read(&mm->mmap_sem);
-	printk("VM: killing process %s\n", tsk->comm);
-	if (user_mode(regs))
-		do_exit(SIGKILL);
-	goto no_context;
+	if (!user_mode(regs))
+		goto no_context;
+	pagefault_out_of_memory();
+	return;
 
 do_sigbus:
 	up_read(&mm->mmap_sem);
--- a/arch/score/mm/fault.c
+++ b/arch/score/mm/fault.c
@@ -172,10 +172,10 @@ out_of_memory:
 		down_read(&mm->mmap_sem);
 		goto survive;
 	}
-	printk("VM: killing process %s\n", tsk->comm);
-	if (user_mode(regs))
-		do_group_exit(SIGKILL);
-	goto no_context;
+	if (!user_mode(regs))
+		goto no_context;
+	pagefault_out_of_memory();
+	return;
 
 do_sigbus:
 	up_read(&mm->mmap_sem);
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -573,10 +573,10 @@ out_of_memory:
 		down_read(&mm->mmap_sem);
 		goto survive;
 	}
-	pr_alert("VM: killing process %s\n", tsk->comm);
-	if (!is_kernel_mode)
-		do_group_exit(SIGKILL);
-	goto no_context;
+	if (is_kernel_mode)
+		goto no_context;
+	pagefault_out_of_memory();
+	return 0;
 
 do_sigbus:
 	up_read(&mm->mmap_sem);


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