From: Michal Hocko <mhocko@suse.cz>
To: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-xtensa@linux-xtensa.org, Chris Zankel <chris@zankel.net>,
Marc Gauthier <Marc.Gauthier@tensilica.com>
Subject: Re: TLB and PTE coherency during munmap
Date: Tue, 28 May 2013 17:16:34 +0200 [thread overview]
Message-ID: <20130528151634.GA30672@dhcp22.suse.cz> (raw)
In-Reply-To: <CAMo8BfJie1Y49QeSJ+JTQb9WsYJkMMkb1BkKz2Gzy3T7V6ogHA@mail.gmail.com>
On Sun 26-05-13 06:50:46, Max Filippov wrote:
> Hello arch and mm people.
>
> Is it intentional that threads of a process that invoked munmap syscall
> can see TLB entries pointing to already freed pages, or it is a bug?
>
> I'm talking about zap_pmd_range and zap_pte_range:
>
> zap_pmd_range
> zap_pte_range
> arch_enter_lazy_mmu_mode
> ptep_get_and_clear_full
> tlb_remove_tlb_entry
> __tlb_remove_page
> arch_leave_lazy_mmu_mode
> cond_resched
>
> With the default arch_{enter,leave}_lazy_mmu_mode, tlb_remove_tlb_entry
> and __tlb_remove_page there is a loop in the zap_pte_range that clears
> PTEs and frees corresponding pages,
The page is not freed at that time (at least not for the generic
mmu_gather implementation). It is stored into mmu_gather and then freed
along with the tlb flush in tlb_flush_mmu.
[...]
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2013-05-28 15:16 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAMo8BfL4QfJrfejNKmBDhAVdmE=_Ys6MVUH5Xa3w_mU41hwx0A@mail.gmail.com>
2013-05-26 2:50 ` Max Filippov
2013-05-28 7:10 ` Max Filippov
2013-05-29 12:27 ` Peter Zijlstra
2013-05-29 12:42 ` Vineet Gupta
2013-05-29 12:47 ` Peter Zijlstra
2013-05-29 17:51 ` Peter Zijlstra
2013-05-29 22:04 ` Catalin Marinas
2013-05-30 6:48 ` Peter Zijlstra
2013-05-30 5:04 ` Vineet Gupta
2013-05-30 6:56 ` Peter Zijlstra
2013-05-30 7:00 ` Vineet Gupta
2013-05-30 11:03 ` Peter Zijlstra
2013-05-31 4:09 ` Max Filippov
2013-05-31 7:55 ` Peter Zijlstra
2013-06-03 9:05 ` Peter Zijlstra
2013-06-03 9:16 ` Ingo Molnar
2013-06-03 10:01 ` Catalin Marinas
2013-06-03 10:04 ` Peter Zijlstra
2013-06-03 10:09 ` Catalin Marinas
2013-06-04 9:52 ` Peter Zijlstra
2013-06-05 0:05 ` Linus Torvalds
2013-06-05 10:26 ` [PATCH] arch, mm: Remove tlb_fast_mode() Peter Zijlstra
2013-05-31 1:40 ` TLB and PTE coherency during munmap Max Filippov
2013-05-28 14:34 ` Konrad Rzeszutek Wilk
2013-05-29 3:23 ` Max Filippov
2013-05-28 15:16 ` Michal Hocko [this message]
2013-05-28 15:23 ` Catalin Marinas
[not found] ` <CAHkRjk4ZNwZvf_Cv+HqfMManodCkEpCPdZokPQ68z3nVG8-+wg@mail.gmail.com>
2013-05-29 4:15 ` Max Filippov
2013-05-29 10:15 ` Catalin Marinas
2013-05-31 1:26 ` Max Filippov
2013-05-31 9:06 ` Catalin Marinas
2013-06-03 9:16 ` Max Filippov
2013-05-29 12:00 ` Vineet Gupta
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