svn commit: r355069 - head/sys/arm/arm

[Ian Lepore]

Author: ian
Date: Sun Nov 24 21:08:56 2019
New Revision: 355069
URL: https://svnweb.freebsd.org/changeset/base/355069

Log:
  When doing ARM stack unwinding as part of stack_save(9), do not search
  loaded modules (pass 0/false for the can_lock arg).  Searching the unwind
  info in modules acquires an exclusive sxlock, and the stack(9) functions can
  be called in a context where unbounded sleeps are forbidden (such as from
  the witness checkorder code).
  
  Just ignoring the existence of modules in stack_save() is not ideal, so I'm
  looking for a better solution, but this commit will make it possible to boot
  an ARM kernel with WITNESS enabled again, until I get something better.
  
  PR:		242200

Modified:
  head/sys/arm/arm/stack_machdep.c

Modified: head/sys/arm/arm/stack_machdep.c
==============================================================================
--- head/sys/arm/arm/stack_machdep.c	Sun Nov 24 20:51:09 2019	(r355068)
+++ head/sys/arm/arm/stack_machdep.c	Sun Nov 24 21:08:56 2019	(r355069)
@@ -40,7 +40,7 @@ stack_capture(struct stack *st, struct unwind_state *s
 {
 
 	stack_zero(st);
-	while (unwind_stack_one(state, 1) == 0) {
+	while (unwind_stack_one(state, 0) == 0) {
 		if (stack_put(st, state->registers[PC]) == -1)
 			break;
 	}