Commit 089ba999 authored Jul 29, 2012 by Oleg Nesterov Committed by Ingo Molnar Jul 30, 2012

uprobes: Kill write_opcode()->lock_page(new_page)



write_opcode() does lock_page(new_page) for no reason. Nobody
can see this page until __replace_page() exposes it under ptl
lock, and we do nothing with this page after pte_unmap_unlock().

If nothing else, the similar code in do_wp_page() doesn't lock
the new page for page_add_new_anon_rmap/set_pte_at_notify.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120729182218.GA20315@redhat.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent c517ee74

kernel/events/uprobes.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -239,9 +239,7 @@ retry:
		if (ret)
		goto unlock_out;

		lock_page(new_page);
		ret = __replace_page(vma, vaddr, old_page, new_page);
		unlock_page(new_page);

		unlock_out:
		unlock_page(old_page);

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