Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> --- man2/userfaultfd.2 | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2 index dc37319..291dd10 100644 --- a/man2/userfaultfd.2 +++ b/man2/userfaultfd.2 @@ -89,6 +89,20 @@ them using the operations described in .BR ioctl_userfaultfd (2). When servicing the page fault events, the fault-handling thread can trigger a wake-up for the sleeping thread. + +It is possible for the faulting threads and the fault-handling threads +to run in the context of different processes. +In this case, these threads may belong to different programs, +and the program that executes the faulting threads +will not necessarily cooperate with the program that handles the page faults. +In such non-cooperative mode, +the process that monitors userfaultfd and handles page faults, +needs to be aware of the changes in the virtual memory layout +of the faulting process to avoid memory corruption. +.\" FIXME elaborate about non-cooperating mode, describe its limitations +.\" for kerneles before 4.11, features added in 4.11 +.\" and limitations remaining in 4.11 +.\" Maybe it's worth adding a dedicated sub-section... .\" .SS Userfaultfd operation After the userfaultfd object is created with -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
