From: Dave Jones <davej@codemonkey.org.uk>
To: x86@kernel.org
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Andi Kleen <ak@linux.intel.com>
Subject: Fix suspicious RCU usage in msr tracing.
Date: Mon, 14 Mar 2016 21:20:54 -0400 [thread overview]
Message-ID: <20160315012054.GA17765@codemonkey.org.uk> (raw)
Since 4.4, I've been able to trigger this occasionally:
===============================
[ INFO: suspicious RCU usage. ]
4.5.0-rc7-think+ #3 Not tainted
-------------------------------
./arch/x86/include/asm/msr-trace.h:47 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 1
RCU used illegally from extended quiescent state!
no locks held by swapper/3/0.
stack backtrace:
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.5.0-rc7-think+ #3
ffffffff92f821e0 1f3e5c340597d7fc ffff880468e07f10 ffffffff92560c2a
ffff880462145280 0000000000000001 ffff880468e07f40 ffffffff921376a6
ffffffff93665ea0 0000cc7c876d28da 0000000000000005 ffffffff9383dd60
Call Trace:
<IRQ> [<ffffffff92560c2a>] dump_stack+0x67/0x9d
[<ffffffff921376a6>] lockdep_rcu_suspicious+0xe6/0x100
[<ffffffff925ae7a7>] do_trace_write_msr+0x127/0x1a0
[<ffffffff92061c83>] native_apic_msr_eoi_write+0x23/0x30
[<ffffffff92054408>] smp_trace_call_function_interrupt+0x38/0x360
[<ffffffff92d1ca60>] trace_call_function_interrupt+0x90/0xa0
<EOI> [<ffffffff92ac5124>] ? cpuidle_enter_state+0x1b4/0x520
[<ffffffff92ac54e7>] cpuidle_enter+0x17/0x20
[<ffffffff9212a984>] cpu_startup_entry+0x4e4/0x610
[<ffffffff9212a4a0>] ? default_idle_call+0x60/0x60
[<ffffffff921908e4>] ? clockevents_config_and_register+0x64/0x70
[<ffffffff92055843>] start_secondary+0x283/0x390
[<ffffffff920555c0>] ? set_cpu_sibling_map+0x970/0x970
Back in January, Andi suggested swapping the order in which
we ack the APIC irq, so it too is protected by rcu.
There was no follow-up, and it seems to work for me.
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index c80f6b6f3da2..e8c4fba52d3d 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -644,8 +644,8 @@ static inline void entering_irq(void)
static inline void entering_ack_irq(void)
{
- ack_APIC_irq();
entering_irq();
+ ack_APIC_irq();
}
static inline void ipi_entering_ack_irq(void)
next reply other threads:[~2016-03-15 1:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-15 1:20 Dave Jones [this message]
2016-03-15 16:39 ` Fix suspicious RCU usage in msr tracing Andi Kleen
2016-03-18 13:54 ` [tip:x86/urgent] x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt() tip-bot for Dave Jones
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160315012054.GA17765@codemonkey.org.uk \
--to=davej@codemonkey.org.uk \
--cc=ak@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.