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From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>, Borislav Petkov <bpetkov@suse.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Brian Gerst <brgerst@gmail.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	stable@vger.kernel.org,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH v2 01/18] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe IRQ tracing
Date: Wed, 22 Nov 2017 06:35:27 +0100	[thread overview]
Message-ID: <20171122053527.eqpuwow3twsl4hc3@gmail.com> (raw)
In-Reply-To: <9150aac013b7b95d62c2336751d5b6e91d2722aa.1511325444.git.luto@kernel.org>


* Andy Lutomirski <luto@kernel.org> wrote:

> When I added entry_SYSCALL_64_after_hwframe, I left TRACE_IRQS_OFF
> before it.  This means that users of entry_SYSCALL_64_after_hwframe
> were responsible for invoking TRACE_IRQS_OFF, and the one and only
> user (added in the same commit) got it wrong.
> 
> I think this would manifest as a warning if a Xen PV guest with
> CONFIG_DEBUG_LOCKDEP=y were used with context tracking.  (The
> context tracking bit is to cause lockdep to get invoked before we
> turn IRQs back on.)  I haven't tested that for real yet because I
> can't get a kernel configured like that to boot at all on Xen PV.
> I've reported it upstream.  The problem seems to be that Xen PV is
> missing early #UD handling, is hitting some WARN, and we rely on

JFYI, seems the changelog got truncated at this point - I simply removed that 
partial sentence as I suppose those details will be explained in the Xen fix 
anyway.

> Move TRACE_IRQS_OFF below the label.

Thanks,

	Ingo

  reply	other threads:[~2017-11-22  5:35 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-22  4:43 [PATCH v2 00/18] Entry stack switching Andy Lutomirski
2017-11-22  4:43 ` [PATCH v2 01/18] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe IRQ tracing Andy Lutomirski
2017-11-22  5:35   ` Ingo Molnar [this message]
2017-11-22  7:45   ` [tip:x86/urgent] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() " tip-bot for Andy Lutomirski
2017-11-22  4:43 ` [PATCH v2 02/18] x86/asm/64: Allocate and enable the SYSENTER stack Andy Lutomirski
2017-11-22  4:43 ` [PATCH v2 03/18] x86/dumpstack: Add get_stack_info() support for " Andy Lutomirski
2017-11-22 12:10   ` Borislav Petkov
2017-11-22  4:43 ` [PATCH v2 04/18] x86/gdt: Put per-cpu GDT remaps in ascending order Andy Lutomirski
2017-11-22 11:05   ` Borislav Petkov
2017-11-22 15:26     ` Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 05/18] x86/fixmap: Generalize the GDT fixmap mechanism Andy Lutomirski
2017-11-22 15:33   ` Borislav Petkov
2017-11-22 17:16     ` Andy Lutomirski
2017-11-22 17:32       ` Borislav Petkov
2017-11-23 15:24         ` Andy Lutomirski
2017-11-23 19:24   ` Thomas Gleixner
2017-11-22  4:44 ` [PATCH v2 06/18] x86/kasan/64: Teach KASAN about the cpu_entry_area Andy Lutomirski
2017-11-22  6:19   ` Ingo Molnar
2017-11-22  9:05   ` Andrey Ryabinin
2017-11-22 15:22     ` Andy Lutomirski
2017-11-23 10:08       ` Andrey Ryabinin
2017-11-23 15:22         ` Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 07/18] x86/asm: Fix assumptions that the HW TSS is at the beginning of cpu_tss Andy Lutomirski
2017-11-22 19:06   ` Borislav Petkov
2017-11-22  4:44 ` [PATCH v2 08/18] x86/dumpstack: Handle stack overflow on all stacks Andy Lutomirski
2017-11-23 11:19   ` Borislav Petkov
2017-11-22  4:44 ` [PATCH v2 09/18] x86/asm: Move SYSENTER_stack to the beginning of struct tss_struct Andy Lutomirski
2017-11-23 12:00   ` Borislav Petkov
2017-11-23 13:16   ` Denys Vlasenko
2017-11-23 15:02     ` Andy Lutomirski
2017-11-23 19:30   ` Thomas Gleixner
2017-11-22  4:44 ` [PATCH v2 10/18] x86/asm: Remap the TSS into the cpu entry area Andy Lutomirski
2017-11-23 19:32   ` Thomas Gleixner
2017-11-23 19:55   ` Borislav Petkov
2017-11-23 20:15     ` Andy Lutomirski
2017-11-23 20:37       ` Borislav Petkov
2017-11-24  2:40         ` Andy Lutomirski
2017-11-24  4:17           ` Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 11/18] x86/asm/64: Separate cpu_current_top_of_stack from TSS.sp0 Andy Lutomirski
2017-11-23 19:34   ` Thomas Gleixner
2017-11-22  4:44 ` [PATCH v2 12/18] x86/espfix/64: Stop assuming that pt_regs is on the entry stack Andy Lutomirski
2017-11-23 19:36   ` Thomas Gleixner
2017-11-22  4:44 ` [PATCH v2 13/18] x86/asm/64: Use a percpu trampoline stack for IDT entries Andy Lutomirski
2017-11-23 23:44   ` Thomas Gleixner
2017-11-24  4:14     ` Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 14/18] x86/asm/64: Return to userspace from the trampoline stack Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 15/18] x86/entry/64: Create a percpu SYSCALL entry trampoline Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 16/18] x86/irq: Remove an old outdated comment about context tracking races Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 17/18] x86/irq/64: In the stack overflow warning, print the offending IP Andy Lutomirski
2017-11-22  4:44 ` [PATCH v2 18/18] x86/entry/64: Move the IST stacks into cpu_entry_area Andy Lutomirski
2017-11-22  6:22 ` [PATCH v2 00/18] Entry stack switching Ingo Molnar
2017-11-22  6:36   ` Ingo Molnar
2017-11-22 16:23   ` Andy Lutomirski
2017-11-23  6:21     ` Ingo Molnar
2017-11-23  6:44       ` Ingo Molnar
2017-11-23  6:58         ` Ingo Molnar
2017-11-23 15:29           ` Andy Lutomirski
2017-11-23 16:41             ` Thomas Gleixner
2017-11-22  7:39 ` WARNING: can't dereference registers at ffffc90004dfff60 for ip error_entry+0x7d/0xd0 (Re: [PATCH v2 00/18] Entry stack switching) Ingo Molnar
2017-11-22  7:43   ` Ingo Molnar
2017-11-22 13:55   ` Josh Poimboeuf
2017-11-22 15:19     ` Andy Lutomirski
2017-11-22 15:56       ` Ingo Molnar
2017-11-22 16:35         ` Andy Lutomirski

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