lkml.org 
[lkml]   [2010]   [Jan]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH] [0/9] SYSCTL: Use RCU to avoid races with string sysctls v2
Date

v2 version that addresses all the earlier review comments
minus patches that were already merged.

I think this one is ready for merge now. Andrew, could you please
take it?

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---

With BKL-less sysctls most of the writable string sysctls are racy. There
is no locking on the reader side, so a reader could see an inconsistent
string or worse miss the terminating null and walk of beyond it.

This patch kit adds a new "rcu string" variant to avoid these
problems and convers the racy users. One the writer side the strings are
always copied to new memory and the readers use rcu_read_lock()
to get a stable view. For readers who access the string over
sleeps the reader copies the string.

This is all hidden in a new generic "rcu_string" ADT which can be also
used for other purposes.

This finally implements all the letters in RCU, most other users
leave out the 'C'.

I left some obscure users in architectures (sparc, mips) alone and audited
all of the others. The sparc reboot_cmd one has references to asm files
which I didn't want to touch and the mips variant seemd just too obscure.

All the others are not racy.

-Andi


\
 
 \ /
  Last update: 2010-01-05 03:17    [W:0.101 / U:0.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site