From nobody Thu Dec 18 23:23:24 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 75CEF20458A for ; Wed, 17 Dec 2025 05:24:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765949050; cv=none; b=RqIpL3odenxWdgGfrvYkR1EX2VOxoGsDjlC6PnTd/u7uih5s54drwS4BdKGyfUGdtcnYtiVeYnjJbXH/nG3uewH5W9nCebLVvKDI22mad+2WhxkJCw4M68gUEdVqiaWwglwGcBAtV6nxpRlMOwc1Z1ywgDm0rY8RklizTvk/uLU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765949050; c=relaxed/simple; bh=0iszWT8aYestMgZ50WGpscZBmgU2zbR56LNh6GrxFNM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BgG6xUXk+O3kPTP3QfgkAP6oflS95sUDoNt1+3qF4SjjCbHOJxhOcpgUR92L5WJuFRp7Tlt4WOjnt4rmm7cEmLtghXMk7NmppxlwmyEcC2RSjlvov0kjb733olZu4+z3cuZNewU7yAUZ1IHddIn39P9WX8xxtXY+TcHtC/UTyuQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cJsVTwna; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cJsVTwna" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB21BC4CEF5; Wed, 17 Dec 2025 05:24:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765949050; bh=0iszWT8aYestMgZ50WGpscZBmgU2zbR56LNh6GrxFNM=; h=From:To:Cc:Subject:Date:From; b=cJsVTwnaNkBPjRJJqQMNSTziehB3SRIaNmx2GlClncPZl2DOyQfG8fJGWZj9kTYVr aXs+M1n0/f6nEPqyJ/j2vpMpdS6t/mSGNRkErNIoJeMWPDKnkn39Z0dww/xY8BFwS3 FN588ryfabIChFL6SL90t7fo47ICEwkmUdlZYbtP0NeeKep74HaY9xXJPSrfw2ttz1 MlN35Kf+UzKoxKYIPRjRINo+yMYK4zTBB9Gps/KhUS0mV9Lw2tSyZEn5LUDSXjy7UP 0Pbn9x8+kUDRtxvla7L+3Svn48tlt2t3j8Ols5/35U3p1itEKmSQgokkC2GcsNdjiZ xWCyXQWNBnSjw== From: Tzung-Bi Shih To: Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng Cc: Waiman Long , linux-kernel@vger.kernel.org, tzungbi@kernel.org Subject: [PATCH v3] lockdep: Add header and footer to surround warning reports Date: Wed, 17 Dec 2025 05:23:53 +0000 Message-ID: <20251217052353.1489154-1-tzungbi@kernel.org> X-Mailer: git-send-email 2.52.0.305.g3fc767764a-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add header and footer to improve log parsing and automated analysis. This makes lockdep output easier to interpret. Signed-off-by: Tzung-Bi Shih --- v3: - Drop meaningless 16 '0's in the footer. v2: https://lore.kernel.org/all/aUCv1B9Bb5CqkKcz@google.com/T/#u - asm/bugs.h -> linux/bug.h. v1: https://lore.kernel.org/all/20251114062730.1828416-1-tzungbi@kernel.org/ kernel/locking/lockdep.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 2d4c5bab5af8..8f5d0166118a 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -58,6 +58,7 @@ #include #include #include +#include =20 #include =20 @@ -110,6 +111,11 @@ static __init int kernel_lockdep_sysctls_init(void) late_initcall(kernel_lockdep_sysctls_init); #endif /* CONFIG_SYSCTL */ =20 +static void print_footer(void) +{ + pr_warn("---[ end trace ]---\n"); +} + DEFINE_PER_CPU(unsigned int, lockdep_recursion); EXPORT_PER_CPU_SYMBOL_GPL(lockdep_recursion); =20 @@ -1958,6 +1964,7 @@ print_circular_bug_header(struct lock_list *entry, un= signed int depth, return; =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: possible circular locking dependency detected\n"); print_kernel_ident(); @@ -2041,6 +2048,7 @@ static noinline void print_circular_bug(struct lock_l= ist *this, =20 printk("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -2561,6 +2569,7 @@ print_bad_irq_dependency(struct task_struct *curr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", irqclass, irqclass); @@ -2614,6 +2623,7 @@ print_bad_irq_dependency(struct task_struct *curr, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); out: nbcon_cpu_emergency_exit(); } @@ -3018,6 +3028,7 @@ print_deadlock_bug(struct task_struct *curr, struct h= eld_lock *prev, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: possible recursive locking detected\n"); print_kernel_ident(); @@ -3039,6 +3050,7 @@ print_deadlock_bug(struct task_struct *curr, struct h= eld_lock *prev, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -3641,6 +3653,7 @@ static void print_collision(struct task_struct *curr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: chain_key collision\n"); print_kernel_ident(); @@ -3656,6 +3669,7 @@ static void print_collision(struct task_struct *curr, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -4013,6 +4027,7 @@ print_usage_bug(struct task_struct *curr, struct held= _lock *this, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: inconsistent lock state\n"); print_kernel_ident(); @@ -4040,6 +4055,7 @@ print_usage_bug(struct task_struct *curr, struct held= _lock *this, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -4079,6 +4095,7 @@ print_irq_inversion_bug(struct task_struct *curr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: possible irq lock inversion dependency detected\n"); print_kernel_ident(); @@ -4123,6 +4140,7 @@ print_irq_inversion_bug(struct task_struct *curr, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); out: nbcon_cpu_emergency_exit(); } @@ -4811,6 +4829,7 @@ print_lock_invalid_wait_context(struct task_struct *c= urr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("[ BUG: Invalid wait context ]\n"); print_kernel_ident(); @@ -4828,6 +4847,7 @@ print_lock_invalid_wait_context(struct task_struct *c= urr, =20 pr_warn("stack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); =20 @@ -5041,6 +5061,7 @@ print_lock_nested_lock_not_held(struct task_struct *c= urr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: Nested lock was not taken\n"); print_kernel_ident(); @@ -5060,6 +5081,7 @@ print_lock_nested_lock_not_held(struct task_struct *c= urr, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -5281,6 +5303,7 @@ static void print_unlock_imbalance_bug(struct task_st= ruct *curr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: bad unlock balance detected!\n"); print_kernel_ident(); @@ -5296,6 +5319,7 @@ static void print_unlock_imbalance_bug(struct task_st= ruct *curr, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -6013,6 +6037,7 @@ static void print_lock_contention_bug(struct task_str= uct *curr, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: bad contention detected!\n"); print_kernel_ident(); @@ -6028,6 +6053,7 @@ static void print_lock_contention_bug(struct task_str= uct *curr, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -6680,6 +6706,7 @@ print_freed_lock_bug(struct task_struct *curr, const = void *mem_from, nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D\n"); pr_warn("WARNING: held lock freed!\n"); print_kernel_ident(); @@ -6691,6 +6718,7 @@ print_freed_lock_bug(struct task_struct *curr, const = void *mem_from, =20 pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -6742,6 +6770,7 @@ static void print_held_locks_bug(void) nbcon_cpu_emergency_enter(); =20 pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: %s/%d still has locks held!\n", current->comm, task_pid_nr(current)); @@ -6750,6 +6779,7 @@ static void print_held_locks_bug(void) lockdep_print_held_locks(current); pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); =20 nbcon_cpu_emergency_exit(); } @@ -6811,6 +6841,7 @@ asmlinkage __visible void lockdep_sys_exit(void) return; nbcon_cpu_emergency_enter(); pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D\n"); pr_warn("WARNING: lock held when returning to user space!\n"); print_kernel_ident(); @@ -6818,6 +6849,7 @@ asmlinkage __visible void lockdep_sys_exit(void) pr_warn("%s/%d is leaving the kernel with locks still held!\n", curr->comm, curr->pid); lockdep_print_held_locks(curr); + print_footer(); nbcon_cpu_emergency_exit(); } =20 @@ -6837,6 +6869,7 @@ void lockdep_rcu_suspicious(const char *file, const i= nt line, const char *s) /* Note: the following can be executed concurrently, so be careful. */ nbcon_cpu_emergency_enter(); pr_warn("\n"); + pr_warn(CUT_HERE); pr_warn("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D\n"); pr_warn("WARNING: suspicious RCU usage\n"); print_kernel_ident(); @@ -6874,6 +6907,7 @@ void lockdep_rcu_suspicious(const char *file, const i= nt line, const char *s) lockdep_print_held_locks(curr); pr_warn("\nstack backtrace:\n"); dump_stack(); + print_footer(); nbcon_cpu_emergency_exit(); warn_rcu_exit(rcu); } --=20 2.52.0.305.g3fc767764a-goog