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From: Andy Lutomirski <luto@amacapital.net>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Andy Lutomirski" <luto@kernel.org>, "X86 ML" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Rik van Riel" <riel@redhat.com>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Denys Vlasenko" <vda.linux@googlemail.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Kees Cook" <keescook@chromium.org>,
	"Brian Gerst" <brgerst@gmail.com>,
	"Paul McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH v5 00/17] x86: Rewrite exit-to-userspace code
Date: Tue, 7 Jul 2015 09:03:32 -0700
Message-ID: <CALCETrX2dzef73rkSNppfSZ+GTTidN36QgzcnxxCbyPUgvyGtA@mail.gmail.com> (raw)
In-Reply-To: <20150707111234.GA13554@gmail.com>

On Tue, Jul 7, 2015 at 4:12 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> So this looks mostly problem free on my boxen, except this warning triggers:
>
> Adding 3911820k swap on /dev/sda2.  Priority:-1 extents:1 across:3911820k
> capability: warning: `dbus-daemon' uses 32-bit capabilities (legacy support in use)
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 2445 at arch/x86/entry/common.c:311 syscall_return_slowpath+0x4c/0x270()
> syscall 6 left IRQs disabled
> Modules linked in:
> CPU: 1 PID: 2445 Comm: distccd Not tainted 4.2.0-rc1-01597-gaecd781-dirty #18
>  0000000000000000 00000000776afac2 ffff880035413e58 ffffffff81c8915f
>  0000000000000000 ffff880035413eb0 ffff880035413e98 ffffffff810a8d82
>  ffff880035413e78 ffff880035413f58 0000000020020002 ffff880035410000
> Call Trace:
>  [<ffffffff81c8915f>] dump_stack+0x4f/0x7b
>  [<ffffffff810a8d82>] warn_slowpath_common+0xa2/0xc0
>  [<ffffffff810a8df5>] warn_slowpath_fmt+0x55/0x70
>  [<ffffffff81001ddc>] syscall_return_slowpath+0x4c/0x270
>  [<ffffffff81c96471>] int_ret_from_sys_call+0x25/0x9f
> ---[ end trace 083efc734e089d37 ]---
> device: 'vcs2': device_add
> PM: Adding info for No Bus:vcs2
> device: 'vcsa2': device_add
>
> with ancient user-space, running the attached .config.
>
> The system booted up fine otherwise. The warning corresponds to:
>
>         if (WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
>                  regs->orig_ax))
>                 local_irq_enable();
>
> and this was just the regular startup of the distccd daemon during bootup, nothing
> particularly fancy.
>
> Note that 'distccd' is a 32-bit ELF binary - and this is a 64-bit kernel.
>
> Syscall 6 would be:
>
> arch/x86/entry/syscalls/syscall_32.tbl:6        i386    close                   sys_close
>
> Thanks,
>
>         Ingo

It's irq state confusion in these lovely macros:

#ifndef CONFIG_AUDITSYSCALL
# define sysexit_audit        ia32_ret_from_sys_call
# define sysretl_audit        ia32_ret_from_sys_call
#endif

Frankly, I'm amazed that the old code seems to have worked.  I should
have a patch for you later today.

--Andy

-- 
Andy Lutomirski
AMA Capital Management, LLC

  reply index

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-03 19:44 Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 01/17] selftests/x86: Add a test for 32-bit fast syscall arg faults Andy Lutomirski
2015-07-07 10:49   ` [tip:x86/asm] x86/entry, " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 02/17] x86/entry/64/compat: Fix bad fast syscall arg failure path Andy Lutomirski
2015-07-07 10:49   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 03/17] uml: Fix do_signal() prototype Andy Lutomirski
2015-07-07 10:49   ` [tip:x86/asm] um: " tip-bot for Ingo Molnar
2015-07-03 19:44 ` [PATCH v5 04/17] context_tracking: Add ct_state and CT_WARN_ON Andy Lutomirski
2015-07-07 10:50   ` [tip:x86/asm] context_tracking: Add ct_state() and CT_WARN_ON() tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 05/17] notifiers: Assert that RCU is watching in notify_die Andy Lutomirski
2015-07-07 10:50   ` [tip:x86/asm] notifiers, RCU: Assert that RCU is watching in notify_die() tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 06/17] x86: Move C entry and exit code to arch/x86/entry/common.c Andy Lutomirski
2015-07-07 10:50   ` [tip:x86/asm] x86/entry: Move C entry and exit code to arch/x86/ entry/common.c tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 07/17] x86/traps: Assert that we're in CONTEXT_KERNEL in exception entries Andy Lutomirski
2015-07-07 10:51   ` [tip:x86/asm] x86/traps, context_tracking: Assert that we' re " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 08/17] x86/entry: Add enter_from_user_mode and use it in syscalls Andy Lutomirski
2015-07-07 10:51   ` [tip:x86/asm] x86/entry: Add enter_from_user_mode() " tip-bot for Andy Lutomirski
2015-07-14 23:00     ` Frederic Weisbecker
2015-07-14 23:04       ` Andy Lutomirski
2015-07-14 23:28         ` Frederic Weisbecker
2015-12-21 20:50   ` [PATCH v5 08/17] x86/entry: Add enter_from_user_mode " Sasha Levin
2015-12-21 22:44     ` Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 09/17] x86/entry: Add new, comprehensible entry and exit hooks Andy Lutomirski
2015-07-07 10:51   ` [tip:x86/asm] x86/entry: Add new, comprehensible entry and exit handlers written in C tip-bot for Andy Lutomirski
2015-07-14 23:07     ` Frederic Weisbecker
2015-07-15 19:56       ` Linus Torvalds
2015-07-15 20:46         ` Andy Lutomirski
2015-07-15 21:25           ` [PATCH] x86/entry: Fix _TIF_USER_RETURN_NOTIFY check in prepare_exit_to_usermode Andy Lutomirski
2015-07-18  3:25             ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 10/17] x86/entry/64: Really create an error-entry-from-usermode code path Andy Lutomirski
2015-07-07 10:52   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 11/17] x86/entry/64: Migrate 64-bit and compat syscalls to new exit hooks Andy Lutomirski
2015-07-07 10:52   ` [tip:x86/asm] x86/entry/64: Migrate 64-bit and compat syscalls to the new exit handlers and remove old assembly code tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 12/17] x86/asm/entry/64: Save all regs on interrupt entry Andy Lutomirski
2015-07-07 10:52   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 13/17] x86/asm/entry/64: Simplify irq stack pt_regs handling Andy Lutomirski
2015-07-07 10:53   ` [tip:x86/asm] x86/asm/entry/64: Simplify IRQ " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 14/17] x86/asm/entry/64: Migrate error and interrupt exit work to C Andy Lutomirski
2015-07-07 10:53   ` [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code tip-bot for Andy Lutomirski
2015-08-11 22:18     ` Frederic Weisbecker
2015-08-11 22:25       ` Andy Lutomirski
2015-08-11 22:49         ` Frederic Weisbecker
2015-08-11 22:59           ` Andy Lutomirski
2015-08-12  1:02             ` Paul E. McKenney
2015-08-12 13:13             ` Frederic Weisbecker
2015-08-11 22:38     ` Frederic Weisbecker
2015-08-11 22:51       ` Andy Lutomirski
2015-08-11 23:22         ` Frederic Weisbecker
2015-08-11 23:33           ` Andy Lutomirski
2015-08-12 13:32             ` Frederic Weisbecker
2015-08-12 14:59               ` Andy Lutomirski
2015-08-18 22:34                 ` Frederic Weisbecker
2015-08-18 22:40                   ` Andy Lutomirski
2015-08-19 17:18                     ` Frederic Weisbecker
2015-08-19 18:02                       ` Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 15/17] x86/entry: Remove exception_enter from most trap handlers Andy Lutomirski
2015-07-07 10:53   ` [tip:x86/asm] x86/entry: Remove exception_enter() " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 16/17] x86/entry: Remove SCHEDULE_USER and asm/context-tracking.h Andy Lutomirski
2015-07-07 10:54   ` [tip:x86/asm] x86/entry: Remove SCHEDULE_USER and asm/ context-tracking.h tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 17/17] x86/irq: Document how IRQ context tracking works and add an assertion Andy Lutomirski
2015-07-07 10:54   ` [tip:x86/asm] x86/irq, context_tracking: Document how IRQ context tracking works and add an RCU assertion tip-bot for Andy Lutomirski
2015-07-14 23:26     ` Frederic Weisbecker
2015-07-14 23:33       ` Andy Lutomirski
2015-07-18 13:23         ` Frederic Weisbecker
2015-07-18 14:10           ` Paul E. McKenney
2015-07-07 11:12 ` [PATCH v5 00/17] x86: Rewrite exit-to-userspace code Ingo Molnar
2015-07-07 16:03   ` Andy Lutomirski [this message]
2015-07-07 17:55     ` [PATCH] x86/entry/64: Fix warning on compat syscalls with CONFIG_AUDITSYSCALL=n Andy Lutomirski
2015-07-08  9:57       ` [tip:x86/asm] x86/entry/64: Fix IRQ state confusion and related warning on compat syscalls with CONFIG_AUDITSYSCALL =n tip-bot for Andy Lutomirski
2015-07-08 19:12       ` tip-bot for Andy Lutomirski

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