Merge tag 'docs-5.11-2' of git://git.lwn.net/linux

[linux-2.6-microblaze.git] / Documentation / admin-guide / sysctl / vm.rst

diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index f455fa0..e35a3f2 100644 (file)
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -146,7 +146,7 @@ This should be used on systems where stalls for minor page faults are an
 acceptable trade for large contiguous free memory.  Set to 0 to prevent
 compaction from moving pages that are unevictable.  Default value is 1.
 On CONFIG_PREEMPT_RT the default value is 0 in order to avoid a page fault, due
-to compaction, which would block the task from becomming active until the fault
+to compaction, which would block the task from becoming active until the fault
 is resolved.
 
 
@@ -428,7 +428,7 @@ While most applications need less than a thousand maps, certain
 programs, particularly malloc debuggers, may consume lots of them,
 e.g., up to one or two maps per allocation.
 
-The default value is 65536.
+The default value is 65530.
 
 
 memory_failure_early_kill:
@@ -873,12 +873,17 @@ file-backed pages is less than the high watermark in a zone.
 unprivileged_userfaultfd
 ========================
 
-This flag controls whether unprivileged users can use the userfaultfd
-system calls.  Set this to 1 to allow unprivileged users to use the
-userfaultfd system calls, or set this to 0 to restrict userfaultfd to only
-privileged users (with SYS_CAP_PTRACE capability).
+This flag controls the mode in which unprivileged users can use the
+userfaultfd system calls. Set this to 0 to restrict unprivileged users
+to handle page faults in user mode only. In this case, users without
+SYS_CAP_PTRACE must pass UFFD_USER_MODE_ONLY in order for userfaultfd to
+succeed. Prohibiting use of userfaultfd for handling faults from kernel
+mode may make certain vulnerabilities more difficult to exploit.
 
-The default value is 1.
+Set this to 1 to allow unprivileged users to use the userfaultfd system
+calls without any restrictions.
+
+The default value is 0.
 
 
 user_reserve_kbytes