| commit | fb842b00c5eab66ec361b31550aa8a922745ce9e | |
| author | Huang Ying <ying.huang@intel.com> | |
| Thu, 13 Jan 2011 00:59:43 +0000 (12 16:59 -0800) | ||
| committer | Linus Torvalds <torvalds@linux-foundation.org> | |
| Thu, 13 Jan 2011 16:03:09 +0000 (13 08:03 -0800) | ||
| tree | cef7e6a0bd01849fcfc911f36293304f9ba7b3c2 | treesnapshot (tar.gz zip) |
| parent | f0f2c2b5b40b5e621a47a6a274117cce77841f1e | commitdiff |
printk: use RCU to prevent potential lock contention in kmsg_dump
dump_list_lock is used to protect dump_list in kmsg_dumper implementation,
kmsg_dump() uses it to traverse dump_list too. But if there is contention
on the lock, kmsg_dump() will fail, and the valuable kernel message may be
lost.
This patch solves this issue with RCU. Because kmsg_dump() only read the
list, no lock is needed in kmsg_dump(). So that kmsg_dump() will never
fail because of lock contention.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dump_list_lock is used to protect dump_list in kmsg_dumper implementation,
kmsg_dump() uses it to traverse dump_list too. But if there is contention
on the lock, kmsg_dump() will fail, and the valuable kernel message may be
lost.
This patch solves this issue with RCU. Because kmsg_dump() only read the
list, no lock is needed in kmsg_dump(). So that kmsg_dump() will never
fail because of lock contention.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| kernel/printk.c | diffblobblamehistory |