From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel@lists.infradead.org,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux-s390@vger.kernel.org,
Sebastian Ott <sebott@linux.vnet.ibm.com>
Subject: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM)
Date: Thu, 11 Feb 2016 19:22:23 +0100 [thread overview]
Message-ID: <20160211192223.4b517057@thinkpad> (raw)
Hi,
Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and
he also bisected this to commit 61f5d698 "mm: re-enable THP". Further
review of the THP rework patches, which cannot be bisected, revealed
commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs"
(and also similar commits for other archs).
This commit removes the THP splitting bit and also the architecture
implementation of pmdp_splitting_flush(), which took care of the IPI for
fast_gup serialization. The commit message says
pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as
needed for fast_gup
The assumption that a TLB flush will also produce an IPI is wrong on s390,
and maybe also on other architectures, and I thought that this was actually
the main reason for having an arch-specific pmdp_splitting_flush().
At least PowerPC and ARM also had an individual implementation of
pmdp_splitting_flush() that used kick_all_cpus_sync() instead of a TLB
flush to send the IPI, and those were also removed. Putting the arch
maintainers and mailing lists on cc to verify.
On s390 this will break the IPI serialization against fast_gup, which
would certainly explain the random kernel crashes, please revert or fix
the pmdp_splitting_flush() removal.
Regards,
Gerald
WARNING: multiple messages have this Message-ID (diff)
From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel@lists.infradead.org,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux-s390@vger.kernel.org,
Sebastian Ott <sebott@linux.vnet.ibm.com>
Subject: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM)
Date: Thu, 11 Feb 2016 19:22:23 +0100 [thread overview]
Message-ID: <20160211192223.4b517057@thinkpad> (raw)
Hi,
Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and
he also bisected this to commit 61f5d698 "mm: re-enable THP". Further
review of the THP rework patches, which cannot be bisected, revealed
commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs"
(and also similar commits for other archs).
This commit removes the THP splitting bit and also the architecture
implementation of pmdp_splitting_flush(), which took care of the IPI for
fast_gup serialization. The commit message says
pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as
needed for fast_gup
The assumption that a TLB flush will also produce an IPI is wrong on s390,
and maybe also on other architectures, and I thought that this was actually
the main reason for having an arch-specific pmdp_splitting_flush().
At least PowerPC and ARM also had an individual implementation of
pmdp_splitting_flush() that used kick_all_cpus_sync() instead of a TLB
flush to send the IPI, and those were also removed. Putting the arch
maintainers and mailing lists on cc to verify.
On s390 this will break the IPI serialization against fast_gup, which
would certainly explain the random kernel crashes, please revert or fix
the pmdp_splitting_flush() removal.
Regards,
Gerald
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WARNING: multiple messages have this Message-ID (diff)
From: gerald.schaefer@de.ibm.com (Gerald Schaefer)
To: linux-arm-kernel@lists.infradead.org
Subject: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM)
Date: Thu, 11 Feb 2016 19:22:23 +0100 [thread overview]
Message-ID: <20160211192223.4b517057@thinkpad> (raw)
Hi,
Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and
he also bisected this to commit 61f5d698 "mm: re-enable THP". Further
review of the THP rework patches, which cannot be bisected, revealed
commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs"
(and also similar commits for other archs).
This commit removes the THP splitting bit and also the architecture
implementation of pmdp_splitting_flush(), which took care of the IPI for
fast_gup serialization. The commit message says
pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as
needed for fast_gup
The assumption that a TLB flush will also produce an IPI is wrong on s390,
and maybe also on other architectures, and I thought that this was actually
the main reason for having an arch-specific pmdp_splitting_flush().
At least PowerPC and ARM also had an individual implementation of
pmdp_splitting_flush() that used kick_all_cpus_sync() instead of a TLB
flush to send the IPI, and those were also removed. Putting the arch
maintainers and mailing lists on cc to verify.
On s390 this will break the IPI serialization against fast_gup, which
would certainly explain the random kernel crashes, please revert or fix
the pmdp_splitting_flush() removal.
Regards,
Gerald
next reply other threads:[~2016-02-11 18:22 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-11 18:22 Gerald Schaefer [this message]
2016-02-11 18:22 ` [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) Gerald Schaefer
2016-02-11 18:22 ` Gerald Schaefer
2016-02-11 19:09 ` Kirill A. Shutemov
2016-02-11 19:09 ` Kirill A. Shutemov
2016-02-11 19:09 ` Kirill A. Shutemov
2016-02-11 19:12 ` Kirill A. Shutemov
2016-02-11 19:12 ` Kirill A. Shutemov
2016-02-11 19:12 ` Kirill A. Shutemov
2016-02-12 12:21 ` Sebastian Ott
2016-02-12 12:21 ` Sebastian Ott
2016-02-12 12:21 ` Sebastian Ott
2016-02-11 19:57 ` Gerald Schaefer
2016-02-11 19:57 ` Gerald Schaefer
2016-02-11 19:57 ` Gerald Schaefer
2016-02-12 4:04 ` Aneesh Kumar K.V
2016-02-12 4:04 ` Aneesh Kumar K.V
2016-02-12 4:04 ` Aneesh Kumar K.V
2016-02-12 11:59 ` Gerald Schaefer
2016-02-12 11:59 ` Gerald Schaefer
2016-02-12 11:59 ` Gerald Schaefer
2016-02-12 16:17 ` Aneesh Kumar K.V
2016-02-12 16:17 ` Aneesh Kumar K.V
2016-02-12 16:17 ` Aneesh Kumar K.V
2016-02-12 10:01 ` Will Deacon
2016-02-12 10:01 ` Will Deacon
2016-02-12 10:01 ` Will Deacon
2016-02-12 10:12 ` Sebastian Ott
2016-02-12 10:12 ` Sebastian Ott
2016-02-12 10:12 ` Sebastian Ott
2016-02-12 15:52 ` Will Deacon
2016-02-12 15:52 ` Will Deacon
2016-02-12 15:52 ` Will Deacon
2016-02-12 15:41 ` Kirill A. Shutemov
2016-02-12 15:41 ` Kirill A. Shutemov
2016-02-12 15:41 ` Kirill A. Shutemov
2016-02-12 15:57 ` Christian Borntraeger
2016-02-12 15:57 ` Christian Borntraeger
2016-02-12 15:57 ` Christian Borntraeger
2016-02-12 17:16 ` Gerald Schaefer
2016-02-12 17:16 ` Gerald Schaefer
2016-02-12 17:16 ` Gerald Schaefer
2016-02-12 23:15 ` Kirill A. Shutemov
2016-02-12 23:15 ` Kirill A. Shutemov
2016-02-12 23:15 ` Kirill A. Shutemov
2016-02-13 11:58 ` Sebastian Ott
2016-02-13 11:58 ` Sebastian Ott
2016-02-13 11:58 ` Sebastian Ott
2016-02-15 11:31 ` Kirill A. Shutemov
2016-02-15 11:31 ` Kirill A. Shutemov
2016-02-15 11:31 ` Kirill A. Shutemov
2016-02-15 16:38 ` Sebastian Ott
2016-02-15 16:38 ` Sebastian Ott
2016-02-15 16:38 ` Sebastian Ott
2016-02-15 18:37 ` Gerald Schaefer
2016-02-15 18:37 ` Gerald Schaefer
2016-02-15 18:37 ` Gerald Schaefer
2016-02-15 18:37 ` Gerald Schaefer
2016-02-15 21:35 ` Kirill A. Shutemov
2016-02-15 21:35 ` Kirill A. Shutemov
2016-02-15 21:35 ` Kirill A. Shutemov
2016-02-16 9:54 ` Sebastian Ott
2016-02-16 9:54 ` Sebastian Ott
2016-02-16 9:54 ` Sebastian Ott
2016-02-16 16:24 ` Gerald Schaefer
2016-02-16 16:24 ` Gerald Schaefer
2016-02-16 16:24 ` Gerald Schaefer
2016-02-16 16:24 ` Gerald Schaefer
2016-02-17 15:04 ` Kirill A. Shutemov
2016-02-17 15:04 ` Kirill A. Shutemov
2016-02-17 15:04 ` Kirill A. Shutemov
2016-02-17 19:04 ` Sebastian Ott
2016-02-17 19:04 ` Sebastian Ott
2016-02-17 19:04 ` Sebastian Ott
2016-02-16 18:46 ` Christian Borntraeger
2016-02-16 18:46 ` Christian Borntraeger
2016-02-16 18:46 ` Christian Borntraeger
2016-02-17 19:13 ` Gerald Schaefer
2016-02-17 19:13 ` Gerald Schaefer
2016-02-17 19:13 ` Gerald Schaefer
2016-02-17 23:58 ` Kirill A. Shutemov
2016-02-17 23:58 ` Kirill A. Shutemov
2016-02-17 23:58 ` Kirill A. Shutemov
2016-02-18 15:00 ` Gerald Schaefer
2016-02-18 15:00 ` Gerald Schaefer
2016-02-18 15:00 ` Gerald Schaefer
2016-02-18 17:06 ` Kirill A. Shutemov
2016-02-18 17:06 ` Kirill A. Shutemov
2016-02-18 17:06 ` Kirill A. Shutemov
2016-02-19 14:15 ` Sebastian Ott
2016-02-19 14:15 ` Sebastian Ott
2016-02-19 14:15 ` Sebastian Ott
2016-02-15 16:41 ` Gerald Schaefer
2016-02-15 16:41 ` Gerald Schaefer
2016-02-15 16:41 ` Gerald Schaefer
2016-02-23 10:32 ` Kirill A. Shutemov
2016-02-23 10:32 ` Kirill A. Shutemov
2016-02-23 10:32 ` Kirill A. Shutemov
2016-02-23 17:46 ` Linus Torvalds
2016-02-23 17:46 ` Linus Torvalds
2016-02-23 17:46 ` Linus Torvalds
2016-02-23 17:46 ` Linus Torvalds
2016-02-23 18:19 ` Gerald Schaefer
2016-02-23 18:19 ` Gerald Schaefer
2016-02-23 18:19 ` Gerald Schaefer
2016-02-23 18:47 ` Will Deacon
2016-02-23 18:47 ` Will Deacon
2016-02-23 18:47 ` Will Deacon
2016-02-25 15:49 ` Steve Capper
2016-02-25 15:49 ` Steve Capper
2016-02-25 15:49 ` Steve Capper
2016-02-25 15:49 ` Steve Capper
2016-02-25 16:01 ` Kirill A. Shutemov
2016-02-25 16:01 ` Kirill A. Shutemov
2016-02-25 16:01 ` Kirill A. Shutemov
2016-02-25 16:01 ` Kirill A. Shutemov
2016-02-25 16:08 ` Steve Capper
2016-02-25 16:08 ` Steve Capper
2016-02-25 16:08 ` Steve Capper
2016-02-25 16:08 ` Steve Capper
2016-02-23 19:33 ` Kirill A. Shutemov
2016-02-23 19:33 ` Kirill A. Shutemov
2016-02-23 19:33 ` Kirill A. Shutemov
2016-02-23 20:22 ` Will Deacon
2016-02-23 20:22 ` Will Deacon
2016-02-23 20:22 ` Will Deacon
2016-02-24 10:16 ` Christian Borntraeger
2016-02-24 10:16 ` Christian Borntraeger
2016-02-24 10:16 ` Christian Borntraeger
2016-02-24 10:41 ` Will Deacon
2016-02-24 10:41 ` Will Deacon
2016-02-24 10:41 ` Will Deacon
2016-02-24 10:51 ` Christian Borntraeger
2016-02-24 10:51 ` Christian Borntraeger
2016-02-24 10:51 ` Christian Borntraeger
2016-02-24 11:02 ` Will Deacon
2016-02-24 11:02 ` Will Deacon
2016-02-24 11:02 ` Will Deacon
2016-02-24 17:22 ` Aneesh Kumar K.V
2016-02-24 17:22 ` Aneesh Kumar K.V
2016-02-24 17:22 ` Aneesh Kumar K.V
2016-02-24 8:39 ` Martin Schwidefsky
2016-02-24 8:39 ` Martin Schwidefsky
2016-02-24 8:39 ` Martin Schwidefsky
2016-02-24 12:11 ` Sebastian Ott
2016-02-24 12:11 ` Sebastian Ott
2016-02-24 12:11 ` Sebastian Ott
2016-02-24 16:44 ` Gerald Schaefer
2016-02-24 16:44 ` Gerald Schaefer
2016-02-24 16:44 ` Gerald Schaefer
2016-02-24 8:22 ` Martin Schwidefsky
2016-02-24 8:22 ` Martin Schwidefsky
2016-02-24 8:22 ` Martin Schwidefsky
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