svn commit: r244296 - head/sys/kern

[Pawel Jakub Dawidek]

Author: pjd
Date: Sun Dec 16 14:53:27 2012
New Revision: 244296
URL: http://svnweb.freebsd.org/changeset/base/244296

Log:
  Move expand_name() after process lock is released.
  
  This fixed panic where we hold mutex (process lock) and try to obtain sleepable
  lock (vnode lock in expand_name()). The panic could occur when %I was used
  in kern.corefile.
  
  Additionally we avoid expand_name() overhead when coredumps are disabled.
  
  Obtained from:	WHEEL Systems

Modified:
  head/sys/kern/kern_sig.c

Modified: head/sys/kern/kern_sig.c
==============================================================================
--- head/sys/kern/kern_sig.c	Sun Dec 16 14:37:25 2012	(r244295)
+++ head/sys/kern/kern_sig.c	Sun Dec 16 14:53:27 2012	(r244296)
@@ -3210,14 +3210,8 @@ coredump(struct thread *td)
 	MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
 	_STOPEVENT(p, S_CORE, 0);
 
-	name = expand_name(p->p_comm, cred->cr_uid, p->p_pid, td, compress);
-	if (name == NULL) {
-		PROC_UNLOCK(p);
-		return (EINVAL);
-	}
 	if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0)) {
 		PROC_UNLOCK(p);
-		free(name, M_TEMP);
 		return (EFAULT);
 	}
 
@@ -3232,11 +3226,14 @@ coredump(struct thread *td)
 	limit = (off_t)lim_cur(p, RLIMIT_CORE);
 	if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
 		PROC_UNLOCK(p);
-		free(name, M_TEMP);
 		return (EFBIG);
 	}
 	PROC_UNLOCK(p);
 
+	name = expand_name(p->p_comm, cred->cr_uid, p->p_pid, td, compress);
+	if (name == NULL)
+		return (EINVAL);
+
 restart:
 	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
 	flags = O_CREAT | FWRITE | O_NOFOLLOW;