From: Oleg Nesterov Date: Tue, 29 May 2012 19:29:28 +0000 (+0200) Subject: uprobes: Change register_for_each_vma() to take mm->mmap_sem for writing X-Git-Tag: v3.6-rc1~167^2~70 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=77fc4af1b59d12ab3b1467adf0a5204806853123;p=pandora-kernel.git uprobes: Change register_for_each_vma() to take mm->mmap_sem for writing Change register_for_each_vma() to take mm->mmap_sem for writing. This is a bit unfortunate but hopefully not too bad, this is the slow path anyway. This is needed to ensure that find_active_uprobe() can not race with uprobe_register() which adds the new bp at the same bp_vaddr, after find_uprobe() fails and before is_swbp_at_addr_fast() checks the memory. IOW, this is needed to ensure that if find_active_uprobe() returns NULL but is_swbp == true, we can safely assume that it was the "normal" int3 and we should send SIGTRAP. There is another reason for this change. We are going to replace uprobes_state->count with MMF_ flags set by register/unregister and cleared by find_active_uprobe(), and set/clear shouldn't race with each other. Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Cc: Ananth N Mavinakayanahalli Cc: Anton Arapov Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120529192928.GE8057@redhat.com Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed