lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 27 Mar 2014 20:43:20 +0900 From: Kazuya Hisaki <kazuya.hisaki.bx@...achi.com> To: unlisted-recipients:; (no To-header on input) Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Theodore Ts'o" <tytso@....edu>, linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de> Subject: [PATCH] random: give up adding randomness to the entropy pool when block devices are busy Hi, This gives up adding randomness to the entropy pool when block devices are busy, to avoid lock contention in I/O intensive situation. Currently randomness is added to the entropy pool for each 4096 I/O completion, and holds a global spinlock during its process. Contention for the spinlock occurs In I/O intensive situation that many cores process I/O completions, even each core processes completion for different block device. This just replaces spin_lock_irqsave() in mix_pool_bytes() with spin_trylock_irqsave(), and gives up adding randomness when trylock is failed. And, it moves trace_mix_pool_bytes() after lock, to trace events only where addition of randomness is executed. Thank you, Signed-off-by: Kazuya Hisaki <kazuya.hisaki.bx@...achi.com> Cc: "Theodore Ts'o" <tytso@....edu> Cc: Arnd Bergmann <arnd@...db.de> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org> Cc: linux-kernel@...r.kernel.org --- drivers/char/random.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 429b75b..d2603f8 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -545,8 +545,9 @@ static void mix_pool_bytes(struct entropy_store *r, const void *in, { unsigned long flags; + if (!spin_trylock_irqsave(&r->lock, flags)) + return; trace_mix_pool_bytes(r->name, nbytes, _RET_IP_); - spin_lock_irqsave(&r->lock, flags); _mix_pool_bytes(r, in, nbytes, out); spin_unlock_irqrestore(&r->lock, flags); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists