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| author |   Oleg Nesterov <oleg@redhat.com> | 2012-07-29 20:22:31 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2012-07-30 11:27:21 +0200 |
| commit | 2fd611a991391a6050cbd139201a2e12fc306540 (patch) | |
| tree | 8233d2ba7dd41e29c6477d4905b6fdc1e7a721e0 /kernel/pid_namespace.c | |
| parent | uprobes: Uprobe_mmap/munmap needs list_for_each_entry_safe() (diff) | |
| download | linux-dev-2fd611a991391a6050cbd139201a2e12fc306540.tar.xz linux-dev-2fd611a991391a6050cbd139201a2e12fc306540.zip | |
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>
Diffstat (limited to 'kernel/pid_namespace.c')
0 files changed, 0 insertions, 0 deletions