| Message ID | 20210720123512.8740-1-will@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Fix arm64 boot regression in 5.14 | expand |
On Tue, 20 Jul 2021 at 14:35, Will Deacon <will@kernel.org> wrote: > > Hi folks, > > Jonathan reports [1] that commit c742199a014d ("mm/pgtable: add stubs > for {pmd/pub}_{set/clear}_huge") breaks the boot on arm64 when huge > mappings are used to map the kernel linear map but the VA size is > configured such that PUDs are folded. This is because the non-functional > pud_set_huge() stub is used to create the linear map, which results in > 1GB holes and a fatal data abort when the kernel attemps to access them. > > Digging further into the issue, it also transpired that huge-vmap is > silently disabled in these configurations as well [2], despite working > correctly in 5.13. The latter issue causes the pgtable selftests to > scream due to a failing consistency check [3]. > > Rather than leave mainline in a terminally broken state for arm64 while > we figure this out, revert the offending commit to get things working > again. Unfortunately, reverting the change in isolation causes a build > breakage for 32-bit PowerPC 8xx machines which recently started relying > on the problematic stubs to support pte-level huge-vmap entries [4]. > Since Christophe is away at the moment, this series first reverts the > PowerPC 8xx change in order to avoid breaking the build. > > I would really like this to land for -rc3 and I can take these via the > arm64 fixes queue if the PowerPC folks are alright with them. > > Cheers, > > Will > > [1] https://lore.kernel.org/r/20210717160118.9855-1-jonathan@marek.ca > [2] https://lore.kernel.org/r/20210719104918.GA6440@willie-the-truck > [3] https://lore.kernel.org/r/CAMuHMdXShORDox-xxaeUfDW3wx2PeggFSqhVSHVZNKCGK-y_vQ@mail.gmail.com/ > [4] https://lore.kernel.org/r/8b972f1c03fb6bd59953035f0a3e4d26659de4f8.1620795204.git.christophe.leroy@csgroup.eu/ > > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Jonathan Marek <jonathan@marek.ca> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Nicholas Piggin <npiggin@gmail.com > Cc: Mike Rapoport <rppt@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Geert Uytterhoeven <geert@linux-m68k.org> > Cc: Marc Zyngier <maz@kernel.org> > Cc: linuxppc-dev@lists.ozlabs.org > Cc: linux-arm-kernel@lists.infradead.org > > --->8 > > Jonathan Marek (1): > Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge" > > Will Deacon (1): > Revert "powerpc/8xx: add support for huge pages on VMAP and VMALLOC" > Reviewed-by: Ard Biesheuvel <ardb@kernel.org> > arch/arm64/mm/mmu.c | 20 ++++----- > arch/powerpc/Kconfig | 2 +- > arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 43 -------------------- > arch/x86/mm/pgtable.c | 34 +++++++--------- > include/linux/pgtable.h | 26 +----------- > 5 files changed, 25 insertions(+), 100 deletions(-) > > -- > 2.32.0.402.g57bb445576-goog >
On 2021-07-20 13:35, Will Deacon wrote: > Hi folks, > > Jonathan reports [1] that commit c742199a014d ("mm/pgtable: add stubs > for {pmd/pub}_{set/clear}_huge") breaks the boot on arm64 when huge > mappings are used to map the kernel linear map but the VA size is > configured such that PUDs are folded. This is because the > non-functional > pud_set_huge() stub is used to create the linear map, which results in > 1GB holes and a fatal data abort when the kernel attemps to access > them. > > Digging further into the issue, it also transpired that huge-vmap is > silently disabled in these configurations as well [2], despite working > correctly in 5.13. The latter issue causes the pgtable selftests to > scream due to a failing consistency check [3]. > > Rather than leave mainline in a terminally broken state for arm64 while > we figure this out, revert the offending commit to get things working > again. Unfortunately, reverting the change in isolation causes a build > breakage for 32-bit PowerPC 8xx machines which recently started relying > on the problematic stubs to support pte-level huge-vmap entries [4]. > Since Christophe is away at the moment, this series first reverts the > PowerPC 8xx change in order to avoid breaking the build. > > I would really like this to land for -rc3 and I can take these via the > arm64 fixes queue if the PowerPC folks are alright with them. > > Cheers, > > Will > > [1] https://lore.kernel.org/r/20210717160118.9855-1-jonathan@marek.ca > [2] https://lore.kernel.org/r/20210719104918.GA6440@willie-the-truck > [3] > https://lore.kernel.org/r/CAMuHMdXShORDox-xxaeUfDW3wx2PeggFSqhVSHVZNKCGK-y_vQ@mail.gmail.com/ > [4] > https://lore.kernel.org/r/8b972f1c03fb6bd59953035f0a3e4d26659de4f8.1620795204.git.christophe.leroy@csgroup.eu/ > > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Jonathan Marek <jonathan@marek.ca> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Nicholas Piggin <npiggin@gmail.com > Cc: Mike Rapoport <rppt@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Geert Uytterhoeven <geert@linux-m68k.org> > Cc: Marc Zyngier <maz@kernel.org> > Cc: linuxppc-dev@lists.ozlabs.org > Cc: linux-arm-kernel@lists.infradead.org > > --->8 > > Jonathan Marek (1): > Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge" > > Will Deacon (1): > Revert "powerpc/8xx: add support for huge pages on VMAP and VMALLOC" > > arch/arm64/mm/mmu.c | 20 ++++----- > arch/powerpc/Kconfig | 2 +- > arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 43 -------------------- > arch/x86/mm/pgtable.c | 34 +++++++--------- > include/linux/pgtable.h | 26 +----------- > 5 files changed, 25 insertions(+), 100 deletions(-) Acked-by: Marc Zyngier <maz@kernel.org> M.
Will Deacon <will@kernel.org> a écrit : > Hi folks, > > Jonathan reports [1] that commit c742199a014d ("mm/pgtable: add stubs > for {pmd/pub}_{set/clear}_huge") breaks the boot on arm64 when huge > mappings are used to map the kernel linear map but the VA size is > configured such that PUDs are folded. This is because the non-functional > pud_set_huge() stub is used to create the linear map, which results in > 1GB holes and a fatal data abort when the kernel attemps to access them. > > Digging further into the issue, it also transpired that huge-vmap is > silently disabled in these configurations as well [2], despite working > correctly in 5.13. The latter issue causes the pgtable selftests to > scream due to a failing consistency check [3]. > > Rather than leave mainline in a terminally broken state for arm64 while > we figure this out, revert the offending commit to get things working > again. Unfortunately, reverting the change in isolation causes a build > breakage for 32-bit PowerPC 8xx machines which recently started relying > on the problematic stubs to support pte-level huge-vmap entries [4]. > Since Christophe is away at the moment, this series first reverts the > PowerPC 8xx change in order to avoid breaking the build. > > I would really like this to land for -rc3 and I can take these via the > arm64 fixes queue if the PowerPC folks are alright with them. > If you can drop patch 1, Change patch 2 to add the two following functions in arch/powerpc/mm/nohash/8xx.c : int pud_clear_huge(pud_t *pud) { return 0; } int pmd_clear_huge(pmd_t *pmd) { return 0; } Then feel free to take it via ARM fixes with my acked-by as maintainer of PPC8XX. Christophe > Cheers, > > Will > > [1] https://lore.kernel.org/r/20210717160118.9855-1-jonathan@marek.ca > [2] https://lore.kernel.org/r/20210719104918.GA6440@willie-the-truck > [3] > https://lore.kernel.org/r/CAMuHMdXShORDox-xxaeUfDW3wx2PeggFSqhVSHVZNKCGK-y_vQ@mail.gmail.com/ > [4] > https://lore.kernel.org/r/8b972f1c03fb6bd59953035f0a3e4d26659de4f8.1620795204.git.christophe.leroy@csgroup.eu/ > > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Jonathan Marek <jonathan@marek.ca> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Nicholas Piggin <npiggin@gmail.com > Cc: Mike Rapoport <rppt@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Geert Uytterhoeven <geert@linux-m68k.org> > Cc: Marc Zyngier <maz@kernel.org> > Cc: linuxppc-dev@lists.ozlabs.org > Cc: linux-arm-kernel@lists.infradead.org > > --->8 > > Jonathan Marek (1): > Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge" > > Will Deacon (1): > Revert "powerpc/8xx: add support for huge pages on VMAP and VMALLOC" > > arch/arm64/mm/mmu.c | 20 ++++----- > arch/powerpc/Kconfig | 2 +- > arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 43 -------------------- > arch/x86/mm/pgtable.c | 34 +++++++--------- > include/linux/pgtable.h | 26 +----------- > 5 files changed, 25 insertions(+), 100 deletions(-) > > -- > 2.32.0.402.g57bb445576-goog
Hi folks, Jonathan reports [1] that commit c742199a014d ("mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge") breaks the boot on arm64 when huge mappings are used to map the kernel linear map but the VA size is configured such that PUDs are folded. This is because the non-functional pud_set_huge() stub is used to create the linear map, which results in 1GB holes and a fatal data abort when the kernel attemps to access them. Digging further into the issue, it also transpired that huge-vmap is silently disabled in these configurations as well [2], despite working correctly in 5.13. The latter issue causes the pgtable selftests to scream due to a failing consistency check [3]. Rather than leave mainline in a terminally broken state for arm64 while we figure this out, revert the offending commit to get things working again. Unfortunately, reverting the change in isolation causes a build breakage for 32-bit PowerPC 8xx machines which recently started relying on the problematic stubs to support pte-level huge-vmap entries [4]. Since Christophe is away at the moment, this series first reverts the PowerPC 8xx change in order to avoid breaking the build. I would really like this to land for -rc3 and I can take these via the arm64 fixes queue if the PowerPC folks are alright with them. Cheers, Will [1] https://lore.kernel.org/r/20210717160118.9855-1-jonathan@marek.ca [2] https://lore.kernel.org/r/20210719104918.GA6440@willie-the-truck [3] https://lore.kernel.org/r/CAMuHMdXShORDox-xxaeUfDW3wx2PeggFSqhVSHVZNKCGK-y_vQ@mail.gmail.com/ [4] https://lore.kernel.org/r/8b972f1c03fb6bd59953035f0a3e4d26659de4f8.1620795204.git.christophe.leroy@csgroup.eu/ Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Paul Mackerras <paulus@samba.org> Cc: Jonathan Marek <jonathan@marek.ca> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com Cc: Mike Rapoport <rppt@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Marc Zyngier <maz@kernel.org> Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-arm-kernel@lists.infradead.org --->8 Jonathan Marek (1): Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge" Will Deacon (1): Revert "powerpc/8xx: add support for huge pages on VMAP and VMALLOC" arch/arm64/mm/mmu.c | 20 ++++----- arch/powerpc/Kconfig | 2 +- arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 43 -------------------- arch/x86/mm/pgtable.c | 34 +++++++--------- include/linux/pgtable.h | 26 +----------- 5 files changed, 25 insertions(+), 100 deletions(-)