From 3a1dfe6eefe483589c99c909202ffe1a20d589b5 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 13 Oct 2008 17:49:02 +0200
Subject: [PATCH] x86/mm: unify init task OOM handling
Linus noticed that the "again:" versus "survive:" OOM logic for
the init task was arbitrarily different.
The 64-bit codepath is the better one, because it correctly re-lookups
the vma after having dropped the ->mmap_sem.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
---
arch/x86/mm/fault.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index ac2ad781da003..8bc5956e1af46 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -671,7 +671,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
goto bad_area_nosemaphore;
again:
- /* When running in the kernel we expect faults to occur only to
+ /*
+ * When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an
* erroneous fault occurring in a code path which already holds mmap_sem
@@ -734,9 +735,6 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
goto bad_area;
}
-#ifdef CONFIG_X86_32
-survive:
-#endif
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
@@ -871,12 +869,11 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
up_read(&mm->mmap_sem);
if (is_global_init(tsk)) {
yield();
-#ifdef CONFIG_X86_32
- down_read(&mm->mmap_sem);
- goto survive;
-#else
+ /*
+ * Re-lookup the vma - in theory the vma tree might
+ * have changed:
+ */
goto again;
-#endif
}
printk("VM: killing process %s\n", tsk->comm);
--
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