From 9fc2552a68eb28f95f367156cf46a3da7843ff37 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sun, 5 Jun 2011 02:24:58 +0100 Subject: [PATCH] ARM: 6952/1: fix lockdep warning of "unannotated irqs-off" This patch fixes the lockdep warning of "unannotated irqs-off"[1]. After entering __irq_usr, arm core will disable interrupt automatically, but __irq_usr does not annotate the irq disable, so lockdep may complain the warning if it has chance to check this in irq handler. This patch adds trace_hardirqs_off in __irq_usr before entering irq_handler to handle the irq, also calls ret_to_user_from_irq to avoid calling disable_irq again. This is also a fix for irq off tracer. [1], lockdep warning log of "unannotated irqs-off" [ 13.804687] ------------[ cut here ]------------ [ 13.809570] WARNING: at kernel/lockdep.c:3335 check_flags+0x78/0x1d0() [ 13.816467] Modules linked in: [ 13.819732] Backtrace: [ 13.822357] [] (dump_backtrace+0x0/0x100) from [] (dump_stack+0x20/0x24) [ 13.831268] r6:c07d8c2c r5:00000d07 r4:00000000 r3:00000000 [ 13.837280] [] (dump_stack+0x0/0x24) from [] (warn_slowpath_common+0x5c/0x74) [ 13.846649] [] (warn_slowpath_common+0x0/0x74) from [] (warn_slowpath_null+0x2c/0x34) [ 13.856781] r8:00000000 r7:00000000 r6:c18b8194 r5:60000093 r4:ef182000 [ 13.863708] r3:00000009 [ 13.866485] [] (warn_slowpath_null+0x0/0x34) from [] (check_flags+0x78/0x1d0) [ 13.875823] [] (check_flags+0x0/0x1d0) from [] (lock_acquire+0x4c/0x150) [ 13.884704] [] (lock_acquire+0x0/0x150) from [] (_raw_spin_lock+0x4c/0x84) [ 13.893798] [] (_raw_spin_lock+0x0/0x84) from [] (sched_ttwu_pending+0x58/0x8c) [ 13.903320] r6:ef92d040 r5:00000003 r4:c18b8180 [ 13.908233] [] (sched_ttwu_pending+0x0/0x8c) from [] (scheduler_ipi+0x18/0x1c) [ 13.917663] r6:ef183fb0 r5:00000003 r4:00000000 r3:00000001 [ 13.923645] [] (scheduler_ipi+0x0/0x1c) from [] (do_IPI+0x9c/0xfc) [ 13.932006] [] (do_IPI+0x0/0xfc) from [] (__irq_usr+0x48/0xe0) [ 13.939971] Exception stack(0xef183fb0 to 0xef183ff8) [ 13.945281] 3fa0: ffffffc3 0001500c 00000001 0001500c [ 13.953948] 3fc0: 00000050 400b45f0 400d9000 00000000 00000001 400d9600 6474e552 bea05b3c [ 13.962585] 3fe0: 400d96c0 bea059c0 400b6574 400b65d8 20000010 ffffffff [ 13.969573] r6:00000403 r5:fa240100 r4:ffffffff r3:20000010 [ 13.975585] ---[ end trace efc4896ab0fb62cb ]--- [ 13.980468] possible reason: unannotated irqs-off. [ 13.985534] irq event stamp: 1610 [ 13.989044] hardirqs last enabled at (1610): [] no_work_pending+0x8/0x2c [ 13.997131] hardirqs last disabled at (1609): [] ret_slow_syscall+0xc/0x1c [ 14.005371] softirqs last enabled at (0): [] copy_process+0x2cc/0xa24 [ 14.013183] softirqs last disabled at (0): [< (null)>] (null) Signed-off-by: Ming Lei Signed-off-by: Russell King --- arch/arm/kernel/entry-armv.S | 6 +++++- arch/arm/kernel/entry-common.S | 2 ++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index e8d885676807..90c62cd51ca9 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -435,6 +435,10 @@ __irq_usr: usr_entry kuser_cmpxchg_check +#ifdef CONFIG_IRQSOFF_TRACER + bl trace_hardirqs_off +#endif + get_thread_info tsk #ifdef CONFIG_PREEMPT ldr r8, [tsk, #TI_PREEMPT] @ get preempt count @@ -453,7 +457,7 @@ __irq_usr: #endif mov why, #0 - b ret_to_user + b ret_to_user_from_irq UNWIND(.fnend ) ENDPROC(__irq_usr) diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 1e7b04a40a31..b2a27b6b0046 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -64,6 +64,7 @@ work_resched: ENTRY(ret_to_user) ret_slow_syscall: disable_irq @ disable interrupts +ENTRY(ret_to_user_from_irq) ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK bne work_pending @@ -75,6 +76,7 @@ no_work_pending: arch_ret_to_user r1, lr restore_user_regs fast = 0, offset = 0 +ENDPROC(ret_to_user_from_irq) ENDPROC(ret_to_user) /* -- GitLab