From: peterz@infradead.org
To: Marco Elver <elver@google.com>
Cc: "Jürgen Groß" <jgross@suse.com>,
fenghua.yu@intel.com, yu-cheng.yu@intel.com, "Luck,
Tony" <tony.luck@intel.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
virtualization@lists.linux-foundation.org,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Steven Rostedt" <rostedt@goodmis.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
syzbot <syzbot+8db9e1ecde74e590a657@syzkaller.appspotmail.com>,
"Wei Liu" <wei.liu@kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>
Subject: Re: [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers
Date: Wed, 12 Aug 2020 10:18:32 +0200 [thread overview]
Message-ID: <20200812081832.GK2674@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200812080650.GA3894595@elver.google.com>
On Wed, Aug 12, 2020 at 10:06:50AM +0200, Marco Elver wrote:
> On Tue, Aug 11, 2020 at 10:17PM +0200, peterz@infradead.org wrote:
> > On Tue, Aug 11, 2020 at 11:46:51AM +0200, peterz@infradead.org wrote:
> >
> > > So let me once again see if I can't find a better solution for this all.
> > > Clearly it needs one :/
> >
> > So the below boots without triggering the debug code from Marco -- it
> > should allow nesting local_irq_save/restore under raw_local_irq_*().
> >
> > I tried unconditional counting, but there's some _reallly_ wonky /
> > asymmetric code that wrecks that and I've not been able to come up with
> > anything useful.
> >
> > This one starts counting when local_irq_save() finds it didn't disable
> > IRQs while lockdep though it did. At that point, local_irq_restore()
> > will decrement and enable things again when it reaches 0.
> >
> > This assumes local_irq_save()/local_irq_restore() are nested sane, which
> > is mostly true.
> >
> > This leaves #PF, which I fixed in these other patches, but I realized it
> > needs fixing for all architectures :-( No bright ideas there yet.
> >
> > ---
> > arch/x86/entry/thunk_32.S | 5 ----
> > include/linux/irqflags.h | 45 +++++++++++++++++++-------------
> > init/main.c | 16 ++++++++++++
> > kernel/locking/lockdep.c | 58 +++++++++++++++++++++++++++++++++++++++++
> > kernel/trace/trace_preemptirq.c | 33 +++++++++++++++++++++++
> > 5 files changed, 134 insertions(+), 23 deletions(-)
>
> Testing this again with syzkaller produced some new reports:
>
> BUG: stack guard page was hit in error_entry
> BUG: stack guard page was hit in exc_int3
> PANIC: double fault in error_entry
> PANIC: double fault in exc_int3
>
> Most of them have corrupted reports, but this one might be useful:
>
> BUG: stack guard page was hit at 000000001fab0982 (stack is 00000000063f33dc..00000000bf04b0d8)
> BUG: stack guard page was hit at 00000000ca97ac69 (stack is 00000000af3e6c84..000000001597e1bf)
> kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP
> CPU: 1 PID: 4709 Comm: kworker/1:1H Not tainted 5.8.0+ #5
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014
> Workqueue: events_highpri snd_vmidi_output_work
> RIP: 0010:exc_int3+0x5/0xf0 arch/x86/kernel/traps.c:636
> Code: c9 85 4d 89 e8 31 c0 e8 a9 7d 68 fd e9 90 fe ff ff e8 0f 35 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 55 53 48 89 fb <e8> 76 0e 00 00 85 c0 74 03 5b 5d c3 f6 83 88 00 00 00 03 74 7e 48
> RSP: 0018:ffffc90008114000 EFLAGS: 00010083
> RAX: 0000000084e00e17 RBX: ffffc90008114018 RCX: ffffffff84e00e17
> RDX: 0000000000000000 RSI: ffffffff84e00a39 RDI: ffffc90008114018
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> FS: 0000000000000000(0000) GS:ffff88807dc80000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffc90008113ff8 CR3: 000000002dae4006 CR4: 0000000000770ee0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> PKRU: 00000000
> Call Trace:
> asm_exc_int3+0x31/0x40 arch/x86/include/asm/idtentry.h:537
> RIP: 0010:arch_static_branch include/trace/events/preemptirq.h:40 [inline]
> RIP: 0010:static_key_false include/linux/jump_label.h:200 [inline]
> RIP: 0010:trace_irq_enable_rcuidle+0xd/0x120 include/trace/events/preemptirq.h:40
> Code: 24 08 48 89 df e8 43 8d ef ff 48 89 df 5b e9 4a 2e 99 03 66 2e 0f 1f 84 00 00 00 00 00 55 41 56 53 48 89 fb e8 84 1a fd ff cc <1f> 44 00 00 5b 41 5e 5d c3 65 8b 05 ab 74 c3 7e 89 c0 31 f6 48 0f
> RSP: 0018:ffffc900081140f8 EFLAGS: 00000093
> RAX: ffffffff813d9e8c RBX: ffffffff81314dd3 RCX: ffff888076ce6000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81314dd3
> RBP: 0000000000000000 R08: ffffffff813da3d4 R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000082 R14: 0000000000000000 R15: ffff888076ce6000
> trace_hardirqs_restore+0x59/0x80 kernel/trace/trace_preemptirq.c:106
> rcu_irq_enter_irqson+0x43/0x70 kernel/rcu/tree.c:1074
> trace_irq_enable_rcuidle+0x87/0x120 include/trace/events/preemptirq.h:40
> trace_hardirqs_restore+0x59/0x80 kernel/trace/trace_preemptirq.c:106
> rcu_irq_enter_irqson+0x43/0x70 kernel/rcu/tree.c:1074
> trace_irq_enable_rcuidle+0x87/0x120 include/trace/events/preemptirq.h:40
> trace_hardirqs_restore+0x59/0x80 kernel/trace/trace_preemptirq.c:106
> rcu_irq_enter_irqson+0x43/0x70 kernel/rcu/tree.c:1074
> trace_irq_enable_rcuidle+0x87/0x120 include/trace/events/preemptirq.h:40
> trace_hardirqs_restore+0x59/0x80 kernel/trace/trace_preemptirq.c:106
> rcu_irq_enter_irqson+0x43/0x70 kernel/rcu/tree.c:1074
>
> <... repeated many many times ...>
>
> trace_irq_enable_rcuidle+0x87/0x120 include/trace/events/preemptirq.h:40
> trace_hardirqs_restore+0x59/0x80 kernel/trace/trace_preemptirq.c:106
> rcu_irq_enter_irqson+0x43/0x70 kernel/rcu/tree.c:1074
> Lost 500 message(s)!
> BUG: stack guard page was hit at 00000000cab483ba (stack is 00000000b1442365..00000000c26f9ad3)
> BUG: stack guard page was hit at 00000000318ff8d8 (stack is 00000000fd87d656..0000000058100136)
> ---[ end trace 4157e0bb4a65941a ]---
Wheee... recursion! Let me try and see if I can make something of that.
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next prev parent reply other threads:[~2020-08-12 8:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <0000000000007d3b2d05ac1c303e@google.com>
[not found] ` <20200805132629.GA87338@elver.google.com>
2020-08-05 13:42 ` [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers peterz
[not found] ` <20200805135940.GA156343@elver.google.com>
2020-08-05 14:12 ` peterz
2020-08-05 14:17 ` Jürgen Groß
2020-08-05 14:17 ` peterz
[not found] ` <CANpmjNN6FWZ+MsAn3Pj+WEez97diHzqF8hjONtHG15C2gSpSgw@mail.gmail.com>
[not found] ` <CANpmjNNy3XKQqgrjGPPKKvXhAoF=mae7dk8hmoS4k4oNnnB=KA@mail.gmail.com>
[not found] ` <20200806074723.GA2364872@elver.google.com>
2020-08-06 11:32 ` peterz
[not found] ` <20200806131702.GA3029162@elver.google.com>
[not found] ` <CANpmjNNqt8YrCad4WqgCoXvH47pRXtSLpnTKhD8W8+UpoYJ+jQ@mail.gmail.com>
[not found] ` <CANpmjNO860SHpNve+vaoAOgarU1SWy8o--tUWCqNhn82OLCiew@mail.gmail.com>
2020-08-07 9:24 ` Jürgen Groß
[not found] ` <20200807095032.GA3528289@elver.google.com>
2020-08-07 10:35 ` Jürgen Groß
[not found] ` <20200807113838.GA3547125@elver.google.com>
2020-08-07 12:04 ` Jürgen Groß
[not found] ` <CANpmjNPau_DEYadey9OL+iFZKEaUTqnFnyFs1dU12o00mg7ofA@mail.gmail.com>
[not found] ` <20200807151903.GA1263469@elver.google.com>
[not found] ` <CANpmjNM1jASqCFYZpteVrZCa2V2D_DbXaqvoCV_Ac2boYfDXnQ@mail.gmail.com>
2020-08-11 7:04 ` Jürgen Groß
2020-08-11 7:41 ` Peter Zijlstra
2020-08-11 7:57 ` Jürgen Groß
2020-08-11 8:12 ` Peter Zijlstra
2020-08-11 8:18 ` Jürgen Groß
2020-08-11 8:38 ` Jürgen Groß
2020-08-11 9:20 ` peterz
2020-08-11 9:46 ` peterz
2020-08-11 20:17 ` peterz
[not found] ` <20200812080650.GA3894595@elver.google.com>
2020-08-12 8:18 ` peterz [this message]
2020-08-12 8:57 ` peterz
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