From 9e0daff30fd7ecf698e5d20b0fa7f851e427cca5 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 13 Apr 2012 11:56:22 -0700 Subject: [PATCH 1/2] sparc64: Fix bootup crash on sun4v. The DS driver registers as a subsys_initcall() but this can be too early, in particular this risks registering before we've had a chance to allocate and setup module_kset in kernel/params.c which is performed also as a subsyts_initcall(). Register DS using device_initcall() insteal. Signed-off-by: David S. Miller Cc: stable@vger.kernel.org --- arch/sparc/kernel/ds.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sparc/kernel/ds.c b/arch/sparc/kernel/ds.c index fea13c7b1aee..b93c2c9ccb1d 100644 --- a/arch/sparc/kernel/ds.c +++ b/arch/sparc/kernel/ds.c @@ -1264,4 +1264,4 @@ static int __init ds_init(void) return vio_register_driver(&ds_driver); } -subsys_initcall(ds_init); +fs_initcall(ds_init); From 3d3eeb2ef26112a200785e5fca58ec58dd33bf1e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 13 Apr 2012 03:35:13 +0000 Subject: [PATCH 2/2] sparc64: Eliminate obsolete __handle_softirq() function The invocation of softirq is now handled by irq_exit(), so there is no need for sparc64 to invoke it on the trap-return path. In fact, doing so is a bug because if the trap occurred in the idle loop, this invocation can result in lockdep-RCU failures. The problem is that RCU ignores idle CPUs, and the sparc64 trap-return path to the softirq handlers fails to tell RCU that the CPU must be considered non-idle while those handlers are executing. This means that RCU is ignoring any RCU read-side critical sections in those handlers, which in turn means that RCU-protected data can be yanked out from under those read-side critical sections. The shiny new lockdep-RCU ability to detect RCU read-side critical sections that RCU is ignoring located this problem. The fix is straightforward: Make sparc64 stop manually invoking the softirq handlers. Reported-by: Meelis Roos Suggested-by: David Miller Signed-off-by: Paul E. McKenney Tested-by: Meelis Roos Cc: stable@vger.kernel.org Signed-off-by: David S. Miller --- arch/sparc/kernel/rtrap_64.S | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/sparc/kernel/rtrap_64.S b/arch/sparc/kernel/rtrap_64.S index 77f1b95e0806..9171fc238def 100644 --- a/arch/sparc/kernel/rtrap_64.S +++ b/arch/sparc/kernel/rtrap_64.S @@ -20,11 +20,6 @@ .text .align 32 -__handle_softirq: - call do_softirq - nop - ba,a,pt %xcc, __handle_softirq_continue - nop __handle_preemption: call schedule wrpr %g0, RTRAP_PSTATE, %pstate @@ -89,9 +84,7 @@ rtrap: cmp %l1, 0 /* mm/ultra.S:xcall_report_regs KNOWS about this load. */ - bne,pn %icc, __handle_softirq ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1 -__handle_softirq_continue: rtrap_xcall: sethi %hi(0xf << 20), %l4 and %l1, %l4, %l4