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Commit 3a1dfe6e authored by Ingo Molnar's avatar Ingo Molnar
Browse files

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: default avatarIngo Molnar <mingo@elte.hu>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 891cffbd

arch/x86/mm/fault.c

+6 −9
Original line number Diff line number Diff line
@@ -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);