From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932091Ab1KHDtF (ORCPT ); Mon, 7 Nov 2011 22:49:05 -0500 Received: from wolverine01.qualcomm.com ([199.106.114.254]:32085 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755319Ab1KHDsz (ORCPT ); Mon, 7 Nov 2011 22:48:55 -0500 X-IronPort-AV: E=McAfee;i="5400,1158,6523"; a="135611803" From: Stephen Boyd To: linux-kernel@vger.kernel.org Cc: Christine Chan , Andrew Morton , Thomas Gleixner , John Stultz Subject: [PATCHv2 2/3] debugobjects: Extend to assert that an object is initialized Date: Mon, 7 Nov 2011 19:48:27 -0800 Message-Id: <1320724108-20788-3-git-send-email-sboyd@codeaurora.org> X-Mailer: git-send-email 1.7.8.rc0.46.g5ae0f In-Reply-To: <1320724108-20788-1-git-send-email-sboyd@codeaurora.org> References: <1320724108-20788-1-git-send-email-sboyd@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christine Chan Calling del_timer_sync() on an uninitialized timer leads to a never ending loop in lock_timer_base() that spins checking for a non-NULL timer base. Add an assertion to debugobjects to catch usage of uninitialized objects so that we can initialize timers in the del_timer_sync() path before it calls lock_timer_base(). Signed-off-by: Christine Chan Cc: Thomas Gleixner Cc: John Stultz Signed-off-by: Andrew Morton [sboyd: Clarify commit message] Signed-off-by: Stephen Boyd --- Documentation/DocBook/debugobjects.tmpl | 50 +++++++++++++++++++++++++++++++ include/linux/debugobjects.h | 6 ++++ lib/debugobjects.c | 38 +++++++++++++++++++++++ 3 files changed, 94 insertions(+), 0 deletions(-) diff --git a/Documentation/DocBook/debugobjects.tmpl b/Documentation/DocBook/debugobjects.tmpl index 08ff908..24979f6 100644 --- a/Documentation/DocBook/debugobjects.tmpl +++ b/Documentation/DocBook/debugobjects.tmpl @@ -96,6 +96,7 @@ debug_object_deactivate debug_object_destroy debug_object_free + debug_object_assert_init Each of these functions takes the address of the real object and a pointer to the object type specific debug description @@ -273,6 +274,26 @@ debug checks. + + + debug_object_assert_init + + This function is called to assert that an object has been + initialized. + + + When the real object is not tracked by debugobjects, it calls + fixup_assert_init of the object type description structure + provided by the caller, with the hardcoded object state + ODEBUG_NOT_AVAILABLE. The fixup function can correct the problem + by calling debug_object_init and other specific initializing + functions. + + + When the real object is already tracked by debugobjects it is + ignored. + + Fixup functions @@ -381,6 +402,35 @@ statistics. + + fixup_assert_init + + This function is called from the debug code whenever a problem + in debug_object_assert_init is detected. + + + Called from debug_object_assert_init() with a hardcoded state + ODEBUG_STATE_NOTAVAILABLE when the object is not found in the + debug bucket. + + + The function returns 1 when the fixup was successful, + otherwise 0. The return value is used to update the + statistics. + + + Note, this function should make sure debug_object_init() is + called before returning. + + + The handling of statically initialized objects is a special + case. The fixup function should check if this is a legitimate + case of a statically initialized object or not. In this case only + debug_object_init() should be called to make the object known to + the tracker. Then the function should return 0 because this is not + a real fixup. + + Known Bugs And Assumptions diff --git a/include/linux/debugobjects.h b/include/linux/debugobjects.h index 65970b8..0e5f578 100644 --- a/include/linux/debugobjects.h +++ b/include/linux/debugobjects.h @@ -46,6 +46,8 @@ struct debug_obj { * fails * @fixup_free: fixup function, which is called when the free check * fails + * @fixup_assert_init: fixup function, which is called when the assert_init + * check fails */ struct debug_obj_descr { const char *name; @@ -54,6 +56,7 @@ struct debug_obj_descr { int (*fixup_activate) (void *addr, enum debug_obj_state state); int (*fixup_destroy) (void *addr, enum debug_obj_state state); int (*fixup_free) (void *addr, enum debug_obj_state state); + int (*fixup_assert_init)(void *addr, enum debug_obj_state state); }; #ifdef CONFIG_DEBUG_OBJECTS @@ -64,6 +67,7 @@ extern void debug_object_activate (void *addr, struct debug_obj_descr *descr); extern void debug_object_deactivate(void *addr, struct debug_obj_descr *descr); extern void debug_object_destroy (void *addr, struct debug_obj_descr *descr); extern void debug_object_free (void *addr, struct debug_obj_descr *descr); +extern void debug_object_assert_init(void *addr, struct debug_obj_descr *descr); /* * Active state: @@ -89,6 +93,8 @@ static inline void debug_object_destroy (void *addr, struct debug_obj_descr *descr) { } static inline void debug_object_free (void *addr, struct debug_obj_descr *descr) { } +static inline void +debug_object_assert_init(void *addr, struct debug_obj_descr *descr) { } static inline void debug_objects_early_init(void) { } static inline void debug_objects_mem_init(void) { } diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 0b07cc5..be066fa 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -570,6 +570,44 @@ out_unlock: } /** + * debug_object_assert_init - debug checks when object should be init-ed + * @addr: address of the object + * @descr: pointer to an object specific debug description structure + */ +void debug_object_assert_init(void *addr, struct debug_obj_descr *descr) +{ + struct debug_bucket *db; + struct debug_obj *obj; + unsigned long flags; + + if (!debug_objects_enabled) + return; + + db = get_bucket((unsigned long) addr); + + raw_spin_lock_irqsave(&db->lock, flags); + + obj = lookup_object(addr, db); + if (!obj) { + struct debug_obj o = { .object = addr, + .state = ODEBUG_STATE_NOTAVAILABLE, + .descr = descr }; + + raw_spin_unlock_irqrestore(&db->lock, flags); + /* + * Maybe the object is static. Let the type specific + * code decide what to do. + */ + if (debug_object_fixup(descr->fixup_assert_init, addr, + ODEBUG_STATE_NOTAVAILABLE)) + debug_print_object(&o, "assert_init"); + return; + } + + raw_spin_unlock_irqrestore(&db->lock, flags); +} + +/** * debug_object_active_state - debug checks object usage state machine * @addr: address of the object * @descr: pointer to an object specific debug description structure -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.