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From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH v2 0/9] ARM: remove set_fs callers and implementation
Date: Sat, 19 Sep 2020 09:19:06 +0100	[thread overview]
Message-ID: <20200919081906.GV1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20200918124624.1469673-1-arnd@arndb.de>

On Fri, Sep 18, 2020 at 02:46:15PM +0200, Arnd Bergmann wrote:
> Hi Christoph, Russell,
> 
> Here is an updated series for removing set_fs() from arch/arm,
> based on the previous feedback.
> 
> I have tested the oabi-compat changes using the LTP tests for the three
> modified syscalls using an Armv7 kernel and a Debian 5 OABI user space,
> and I have lightly tested the get_kernel_nofault infrastructure by
> loading the test_lockup.ko module after setting CONFIG_DEBUG_SPINLOCK.

I'm not too keen on always saving the syscall number, but for the gain
of getting rid of set_fs() I think it's worth it. However...

I think there are some things to check - what value do you end up
with as the first number in /proc/self/syscall when you do:

strace cat /proc/self/syscall

?

It should be 3, not 0x900003. I suspect you're getting the latter
with these changes.  IIRC, task_thread_info(task)->syscall needs to
be the value _without_ the offset, otherwise tracing will break.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>,
	linux-mm@kvack.org, Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 0/9] ARM: remove set_fs callers and implementation
Date: Sat, 19 Sep 2020 09:19:06 +0100	[thread overview]
Message-ID: <20200919081906.GV1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20200918124624.1469673-1-arnd@arndb.de>

On Fri, Sep 18, 2020 at 02:46:15PM +0200, Arnd Bergmann wrote:
> Hi Christoph, Russell,
> 
> Here is an updated series for removing set_fs() from arch/arm,
> based on the previous feedback.
> 
> I have tested the oabi-compat changes using the LTP tests for the three
> modified syscalls using an Armv7 kernel and a Debian 5 OABI user space,
> and I have lightly tested the get_kernel_nofault infrastructure by
> loading the test_lockup.ko module after setting CONFIG_DEBUG_SPINLOCK.

I'm not too keen on always saving the syscall number, but for the gain
of getting rid of set_fs() I think it's worth it. However...

I think there are some things to check - what value do you end up
with as the first number in /proc/self/syscall when you do:

strace cat /proc/self/syscall

?

It should be 3, not 0x900003. I suspect you're getting the latter
with these changes.  IIRC, task_thread_info(task)->syscall needs to
be the value _without_ the offset, otherwise tracing will break.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-09-19  8:19 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-18 12:46 [PATCH v2 0/9] ARM: remove set_fs callers and implementation Arnd Bergmann
2020-09-18 12:46 ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 1/9] mm/maccess: fix unaligned copy_{from,to}_kernel_nofault Arnd Bergmann
2020-09-18 12:46   ` [PATCH v2 1/9] mm/maccess: fix unaligned copy_{from, to}_kernel_nofault Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 2/9] ARM: traps: use get_kernel_nofault instead of set_fs() Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-19  5:27   ` Christoph Hellwig
2020-09-19  5:27     ` Christoph Hellwig
2020-09-18 12:46 ` [PATCH v2 3/9] ARM: oabi-compat: add epoll_pwait handler Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-21 12:54   ` Sasha Levin
2020-09-21 13:27     ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 4/9] ARM: syscall: always store thread_info->syscall Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 5/9] ARM: oabi-compat: rework epoll_wait/epoll_pwait emulation Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-19  5:32   ` Christoph Hellwig
2020-09-19  5:32     ` Christoph Hellwig
2020-09-26 18:30     ` Arnd Bergmann
2020-09-26 18:30       ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 6/9] ARM: oabi-compat: rework sys_semtimedop emulation Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 7/9] ARM: oabi-compat: rework fcntl64() emulation Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 8/9] ARM: uaccess: add __{get,put}_kernel_nofault Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-18 12:46 ` [PATCH v2 9/9] ARM: uaccess: remove set_fs() implementation Arnd Bergmann
2020-09-18 12:46   ` Arnd Bergmann
2020-09-19  5:27 ` [PATCH v2 0/9] ARM: remove set_fs callers and implementation Christoph Hellwig
2020-09-19  5:27   ` Christoph Hellwig
2020-09-25 13:40   ` Arnd Bergmann
2020-09-25 13:40     ` Arnd Bergmann
2020-09-26  6:49     ` Christoph Hellwig
2020-09-26  6:49       ` Christoph Hellwig
2021-07-05  6:01     ` Christoph Hellwig
2021-07-05  6:01       ` Christoph Hellwig
2021-07-22 17:27       ` Arnd Bergmann
2021-07-22 17:27         ` Arnd Bergmann
2020-09-19  8:19 ` Russell King - ARM Linux admin [this message]
2020-09-19  8:19   ` Russell King - ARM Linux admin
2020-09-25 14:08   ` Arnd Bergmann
2020-09-25 14:08     ` Arnd Bergmann
2020-09-25 15:30     ` Arnd Bergmann
2020-09-25 15:30       ` Arnd Bergmann

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