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authorHaren Myneni <haren@us.ibm.com>2005-08-03 15:08:18 +1000
committerLinus Torvalds <torvalds@g5.osdl.org>2005-08-02 22:16:45 -0700
commit5cb4cc0d8211c490537c8568001958fc76741312 (patch)
tree3a3844a79cff56d84ecafd65ba5d8da25e158d2b
parent0b2bfb4e7ff61f286676867c3508569bea6fbf7a (diff)
[PATCH] Xmon bug fix for soft-reset
For soft reset during system hang, got an error "CPU did not take control" for some CPUs even though they responded to soft-reset (called SystemReset, die and called debugger - xmon). First these CPUs entered into xmon by IPI callback and then got a soft-reset exception and re-entered into xmon again. The first CPU which re-entered into xmon got the output lock and made into xmon successfully without unlocking. Hence, the next CPU(s) which re-entered into xmon try to acquire a lock (get_output_lock). Therefore, we can not view state of those CPU(s). [This is a simple, very low risk, obvious fix for an obvious bug, and should go into 2.6.13. -- paulus] Signed-off-by: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/ppc64/xmon/xmon.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/ppc64/xmon/xmon.c b/arch/ppc64/xmon/xmon.c
index 7f6e13a4b71..05539439e6b 100644
--- a/arch/ppc64/xmon/xmon.c
+++ b/arch/ppc64/xmon/xmon.c
@@ -329,13 +329,16 @@ int xmon_core(struct pt_regs *regs, int fromipi)
printf("cpu 0x%x: Exception %lx %s in xmon, "
"returning to main loop\n",
cpu, regs->trap, getvecname(TRAP(regs)));
+ release_output_lock();
longjmp(xmon_fault_jmp[cpu], 1);
}
if (setjmp(recurse_jmp) != 0) {
if (!in_xmon || !xmon_gate) {
+ get_output_lock();
printf("xmon: WARNING: bad recursive fault "
"on cpu 0x%x\n", cpu);
+ release_output_lock();
goto waiting;
}
secondary = !(xmon_taken && cpu == xmon_owner);