Home
last modified time | relevance | path

Searched hist:"2 fd611a9" (Results 1 – 1 of 1) sorted by relevance

/openbmc/linux/kernel/events/
H A Duprobes.c2fd611a9 Sun Jul 29 13:22:31 CDT 2012 Oleg Nesterov <oleg@redhat.com> uprobes: Suppress uprobe_munmap() from mmput()

uprobe_munmap() does get_user_pages() and it is also called from
the final mmput()->exit_mmap() path. This slows down
exit/mmput() for no reason, and I think it is simply
dangerous/wrong to try to fault-in a page into the dying mm. If
nothing else, this happens after the last sync_mm_rss(), afaics
handle_mm_fault() can change the task->rss_stat and make the
subsequent check_mm() unhappy.

Change uprobe_munmap() to check mm->mm_users != 0.

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/20120729182231.GA20336@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2fd611a9 Sun Jul 29 13:22:31 CDT 2012 Oleg Nesterov <oleg@redhat.com> uprobes: Suppress uprobe_munmap() from mmput()

uprobe_munmap() does get_user_pages() and it is also called from
the final mmput()->exit_mmap() path. This slows down
exit/mmput() for no reason, and I think it is simply
dangerous/wrong to try to fault-in a page into the dying mm. If
nothing else, this happens after the last sync_mm_rss(), afaics
handle_mm_fault() can change the task->rss_stat and make the
subsequent check_mm() unhappy.

Change uprobe_munmap() to check mm->mm_users != 0.

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/20120729182231.GA20336@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>