From: peterz@infradead.org
To: Marco Elver <elver@google.com>
Cc: tglx@linutronix.de, mingo@kernel.org, will@kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org, paulmck@kernel.org,
rostedt@goodmis.org, rjw@rjwysocki.net
Subject: Re: [RFC][PATCH 0/3] Tracing, Idle, RCU and such goodness
Date: Mon, 10 Aug 2020 14:11:38 +0200 [thread overview]
Message-ID: <20200810121138.GV2674@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200810095535.GA1597985@elver.google.com>
On Mon, Aug 10, 2020 at 11:55:35AM +0200, Marco Elver wrote:
> Unfortunately I get LOCKDEP_DEBUG warnings, when testing with one of
> syzbot's configs. This appears at some point during boot (no other
> test):
>
> DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())
> WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:4875 check_flags+0x52/0x200 kernel/locking/lockdep.c:4875
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.8.0+ #8
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014
> RIP: 0010:check_flags+0x52/0x200 kernel/locking/lockdep.c:4875
> Code: c0 74 48 e8 40 f7 a5 03 85 c0 74 20 83 3d bd 33 53 05 00 75 17 48 c7 c7 ce 12 c9 85 48 c7 c6 04 8c ca 85 31 c0 e8 4e c1 f7 ff <0f> 0b 48 c7 c7 db 8b ca 85 e9 8c 01 00 00 85 c0 75 0f 65 8b 05 c5
> RSP: 0000:ffffffff86203bf0 EFLAGS: 00010046
> RAX: 1f9fa70771052a00 RBX: 0000000000000000 RCX: ffffffff8627e980
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 0000000000000000 R08: ffffffff813d8494 R09: 0000000000000000
> R10: 0000000000000012 R11: ffffffff8627e980 R12: ffffffff8627e980
> R13: ffffffff862e3420 R14: 00000000ffffffff R15: 0000000000000046
> FS: 0000000000000000(0000) GS:ffff88881fa00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffff88883ffff000 CR3: 0000000006275001 CR4: 0000000000770ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> PKRU: 00000000
> Call Trace:
> lock_is_held_type+0x4d/0x110 kernel/locking/lockdep.c:5043
> lock_is_held include/linux/lockdep.h:266 [inline]
> rcu_read_lock_sched_held+0x41/0x90 kernel/rcu/update.c:136
> trace_lock_acquire+0x49/0x120 include/trace/events/lock.h:13
> lock_acquire+0x8d/0x2c0 kernel/locking/lockdep.c:5003
> mutex_trylock+0xdd/0x120 kernel/locking/mutex.c:1420
*groan*, indeed! Which is the direct result of lockdep recursion because
we pulled that tracepoint out from under the recursion thing.
Let me go prod this with a sharp stick...
next prev parent reply other threads:[~2020-08-10 12:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 19:23 [RFC][PATCH 0/3] Tracing, Idle, RCU and such goodness Peter Zijlstra
2020-08-07 19:23 ` [RFC][PATCH 1/3] sched,idle,rcu: Push rcu_idle deeper into the idle path Peter Zijlstra
2020-08-07 19:23 ` [RFC][PATCH 2/3] locking,entry: #PF vs TRACE_IRQFLAGS Peter Zijlstra
2020-08-07 20:21 ` Steven Rostedt
2020-08-10 11:57 ` peterz
2020-08-10 12:05 ` David Laight
2020-08-10 13:49 ` peterz
2020-08-07 19:23 ` [RFC][PATCH 3/3] lockdep,trace: Expose tracepoints Peter Zijlstra
2020-08-07 20:34 ` Steven Rostedt
2020-08-10 12:26 ` [RFC][PATCH v1.1 " peterz
2020-08-10 9:55 ` [RFC][PATCH 0/3] Tracing, Idle, RCU and such goodness Marco Elver
2020-08-10 12:11 ` peterz [this message]
2020-08-11 16:08 ` Paul E. McKenney
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