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author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-02-05 16:00:58 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-22 15:11:08 +0300 |
commit | 42a9a7e807505b485f7c6a7ffb0ffb7dab8e1b51 (patch) | |
tree | d25b0e4cc82dfc23b842b7c0e0e1ded63323f53e /Documentation/admin-guide | |
parent | 373ef51f3e8ac62ee12aeb53f0ca81ec50160b0b (diff) | |
download | linux-42a9a7e807505b485f7c6a7ffb0ffb7dab8e1b51.tar.xz |
random: always wake up entropy writers after extraction
commit 489c7fc44b5740d377e8cfdbf0851036e493af00 upstream.
Now that POOL_BITS == POOL_MIN_BITS, we must unconditionally wake up
entropy writers after every extraction. Therefore there's no point of
write_wakeup_threshold, so we can move it to the dustbin of unused
compatibility sysctls. While we're at it, we can fix a small comparison
where we were waking up after <= min rather than < min.
Cc: Theodore Ts'o <tytso@mit.edu>
Suggested-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 44 |
1 files changed, 42 insertions, 2 deletions
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 7b477fa19534..89214744eae2 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -862,9 +862,49 @@ The kernel command line parameter printk.devkmsg= overrides this and is a one-time setting until next reboot: once set, it cannot be changed by this sysctl interface anymore. +pty +=== -randomize_va_space: -=================== +See Documentation/filesystems/devpts.rst. + + +random +====== + +This is a directory, with the following entries: + +* ``boot_id``: a UUID generated the first time this is retrieved, and + unvarying after that; + +* ``entropy_avail``: the pool's entropy count, in bits; + +* ``poolsize``: the entropy pool size, in bits; + +* ``urandom_min_reseed_secs``: obsolete (used to determine the minimum + number of seconds between urandom pool reseeding). This file is + writable for compatibility purposes, but writing to it has no effect + on any RNG behavior. + +* ``uuid``: a UUID generated every time this is retrieved (this can + thus be used to generate UUIDs at will); + +* ``write_wakeup_threshold``: when the entropy count drops below this + (as a number of bits), processes waiting to write to ``/dev/random`` + are woken up. This file is writable for compatibility purposes, but + writing to it has no effect on any RNG behavior. + +If ``drivers/char/random.c`` is built with ``ADD_INTERRUPT_BENCH`` +defined, these additional entries are present: + +* ``add_interrupt_avg_cycles``: the average number of cycles between + interrupts used to feed the pool; + +* ``add_interrupt_avg_deviation``: the standard deviation seen on the + number of cycles between interrupts used to feed the pool. + + +randomize_va_space +================== This option can be used to select the type of process address space randomization that is used in the system, for architectures |