Re: [PATCH stable-rc queue/4.9 1/1] futex: Provide distinct return value when owner is exiting
From: Greg KH
Date: Wed Feb 24 2021 - 02:48:28 EST
On Wed, Feb 24, 2021 at 09:41:01AM +0800, Xiaoming Ni wrote:
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On 2021年2月23日 21:00, Greg KH wrote:
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> On Mon, Feb 22, 2021 at 10:11:37PM +0800, Xiaoming Ni wrote:
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> > On 2021年2月22日 20:09, Greg KH wrote:
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> > > On Mon, Feb 22, 2021 at 06:54:06PM +0800, Xiaoming Ni wrote:
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> > > > On 2021年2月22日 18:16, Greg KH wrote:
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> > > > > On Mon, Feb 22, 2021 at 03:03:28PM +0800, Xiaoming Ni wrote:
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> > > > > > From: Thomas Gleixner<tglx@xxxxxxxxxxxxx>
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> > > > > >
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> > > > > > commit ac31c7ff8624409ba3c4901df9237a616c187a5d upstream.
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> > > > > This commit is already in the 4.9 tree. If the backport was incorrect,
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> > > > > say that here, and describe what went wrong and why this commit fixes
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> > > > > it.
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> > > > >
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> > > > > Also state what commit this fixes as well, otherwise this changelog just
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> > > > > looks like it is being applied again to the tree, which doesn't make
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> > > > > much sense.
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> > > > >
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> > > > > thanks,
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> > > > >
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> > > > > greg k-h
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> > > > > .
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> > > >
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> > > > I wrote a cover for it. but forgot to adjust the title of the cover:
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> > > >
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> > > > https://lore.kernel.org/lkml/20210222070328.102384-1-nixiaoming@xxxxxxxxxx/
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> > > >
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> > > >
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> > > > I found a dead code in the queue/4.9 branch of the stable-rc repository.
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> > > >
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> > > > 2021年02月03日:
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> > > > commit c27f392040e2f6 ("futex: Provide distinct return value when
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> > > > owner is exiting")
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> > > > The function handle_exit_race does not exist. Therefore, the
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> > > > change in handle_exit_race() is ignored in the patch round.
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> > > >
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> > > > 2021年02月22日:
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> > > > commit e55cb811e612 ("futex: Cure exit race")
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> > > > Define the handle_exit_race() function,
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> > > > but no branch in the function returns EBUSY.
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> > > > As a result, dead code occurs in the attach_to_pi_owner():
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> > > >
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> > > > int ret = handle_exit_race(uaddr, uval, p);
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> > > > ...
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> > > > if (ret == -EBUSY)
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> > > > *exiting = p; /* dead code */
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> > > >
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> > > > To fix the dead code, modify the commit e55cb811e612 ("futex: Cure exit
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> > > > race"),
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> > > > or install a patch to incorporate the changes in handle_exit_race().
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> > > >
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> > > > I am unfamiliar with the processing of the stable-rc queue branch,
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> > > > and I cannot find the patch mail of the current branch in
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> > > > https://lore.kernel.org/lkml/?q=%22futex%3A+Cure+exit+race%22
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> > > > Therefore, I re-integrated commit ac31c7ff8624 ("futex: Provide distinct
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> > > > return value when owner is exiting").
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> > > > And wrote a cover (but forgot to adjust the title of the cover):
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> > > >
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> > > > https://lore.kernel.org/lkml/20210222070328.102384-1-nixiaoming@xxxxxxxxxx/
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> > >
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> > > So this is a "fixup" patch, right?
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> > >
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> > > Please clearly label it as such in your patch description and resend
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> > > this as what is here I can not apply at all.
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> > >
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> > > thanks,
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> > >
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> > > greg k-h
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> > > .
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> > >
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> > Thank you for your guidance.
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> > I have updated the patch description and resent the patch based on
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> > v4.9.258-rc1
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> > https://lore.kernel.org/lkml/20210222125352.110124-1-nixiaoming@xxxxxxxxxx/
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>
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> Can you please try 4.9.258 and let me know if this is still needed or
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> not?
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>
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> thanks,
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>
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> greg k-h
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> .
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>
>
The dead code problem still exists in V4.9.258. No conflict occurs during my
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patch integration. Do I need to correct the version number marked in the cc
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table in the patch and resend the patch?
Please do.
thanks,
greg k-h