From f09ac9db2aafe36fde9ebd63c8c5d776f6e7bd41 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Fri, 18 Apr 2008 10:11:04 -0400 Subject: [PATCH] Audit: stop deadlock from signals under load A deadlock is possible between kauditd and auditd under load if auditd receives a signal. When auditd receives a signal it sends a netlink message to the kernel asking for information about the sender of the signal. In that same context the audit system will attempt to send a netlink message back to the userspace auditd. If kauditd has already filled the socket buffer (see netlink_attachskb()) auditd will now put itself to sleep waiting for room to send the message. Since auditd is responsible for draining that socket we have a deadlock. The fix, since the response from the kernel does not need to be synchronous is to send the signal information back to auditd in a separate thread. And thus auditd can continue to drain the audit queue normally. Signed-off-by: Eric Paris Signed-off-by: Al Viro --- Reading git-format-patch failed