linux-stable.git/arch, branch v6.4.10 Linux kernel stable tree x86/CPU/AMD: Do not leak quotient data after a division by 0 2023-08-11T10:14:29+00:00 Borislav Petkov (AMD) bp@alien8.de 2023-08-04T22:06:43+00:00 c9c0b889e2d33d49b06bb716b95a192ed3449173 commit 77245f1c3c6495521f6a3af082696ee2f8ce3921 upstream. Under certain circumstances, an integer division by 0 which faults, can leave stale quotient data from a previous division operation on Zen1 microarchitectures. Do a dummy division 0/1 before returning from the #DE exception handler in order to avoid any leaks of potentially sensitive data. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: <stable@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 77245f1c3c6495521f6a3af082696ee2f8ce3921 upstream.

Under certain circumstances, an integer division by 0 which faults, can
leave stale quotient data from a previous division operation on Zen1
microarchitectures.

Do a dummy division 0/1 before returning from the #DE exception handler
in order to avoid any leaks of potentially sensitive data.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: dts: nxp/imx6sll: fix wrong property name in usbphy node 2023-08-11T10:14:27+00:00 Xu Yang xu.yang_2@nxp.com 2023-07-17T02:28:33+00:00 7f87080d2e9744f67da17121363729c21cba4e53 [ Upstream commit ee70b908f77a9d8f689dea986f09e6d7dc481934 ] Property name "phy-3p0-supply" is used instead of "phy-reg_3p0-supply". Fixes: 9f30b6b1a957 ("ARM: dts: imx: Add basic dtsi file for imx6sll") cc: <stable@vger.kernel.org> Signed-off-by: Xu Yang <xu.yang_2@nxp.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ee70b908f77a9d8f689dea986f09e6d7dc481934 ]

Property name "phy-3p0-supply" is used instead of "phy-reg_3p0-supply".

Fixes: 9f30b6b1a957 ("ARM: dts: imx: Add basic dtsi file for imx6sll")
cc: <stable@vger.kernel.org>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/mm/altmap: Fix altmap boundary check 2023-08-11T10:14:27+00:00 Aneesh Kumar K.V aneesh.kumar@linux.ibm.com 2023-07-24T18:13:20+00:00 bbfa34c97d8b8e2e12647cd4dc2f141ae241d90a [ Upstream commit 6722b25712054c0f903b839b8f5088438dd04df3 ] altmap->free includes the entire free space from which altmap blocks can be allocated. So when checking whether the kernel is doing altmap block free, compute the boundary correctly, otherwise memory hotunplug can fail. Fixes: 9ef34630a461 ("powerpc/mm: Fallback to RAM if the altmap is unusable") Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230724181320.471386-1-aneesh.kumar@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 6722b25712054c0f903b839b8f5088438dd04df3 ]

altmap->free includes the entire free space from which altmap blocks
can be allocated. So when checking whether the kernel is doing altmap
block free, compute the boundary correctly, otherwise memory hotunplug
can fail.

Fixes: 9ef34630a461 ("powerpc/mm: Fallback to RAM if the altmap is unusable")
Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230724181320.471386-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
arm64/ptrace: Don't enable SVE when setting streaming SVE 2023-08-11T10:14:23+00:00 Mark Brown broonie@kernel.org 2023-08-03T18:33:21+00:00 64b7ae70678bb074f1b7e606483ff24ca36764e2 commit 045aecdfcb2e060db142d83a0f4082380c465d2c upstream. Systems which implement SME without also implementing SVE are architecturally valid but were not initially supported by the kernel, unfortunately we missed one issue in the ptrace code. The SVE register setting code is shared between SVE and streaming mode SVE. When we set full SVE register state we currently enable TIF_SVE unconditionally, in the case where streaming SVE is being configured on a system that supports vanilla SVE this is not an issue since we always initialise enough state for both vector lengths but on a system which only support SME it will result in us attempting to restore the SVE vector length after having set streaming SVE registers. Fix this by making the enabling of SVE conditional on setting SVE vector state. If we set streaming SVE state and SVE was not already enabled this will result in a SVE access trap on next use of normal SVE, this will cause us to flush our register state but this is fine since the only way to trigger a SVE access trap would be to exit streaming mode which will cause the in register state to be flushed anyway. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-1-49df214bfb3e@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 045aecdfcb2e060db142d83a0f4082380c465d2c upstream.

Systems which implement SME without also implementing SVE are
architecturally valid but were not initially supported by the kernel,
unfortunately we missed one issue in the ptrace code.

The SVE register setting code is shared between SVE and streaming mode
SVE. When we set full SVE register state we currently enable TIF_SVE
unconditionally, in the case where streaming SVE is being configured on a
system that supports vanilla SVE this is not an issue since we always
initialise enough state for both vector lengths but on a system which only
support SME it will result in us attempting to restore the SVE vector
length after having set streaming SVE registers.

Fix this by making the enabling of SVE conditional on setting SVE vector
state. If we set streaming SVE state and SVE was not already enabled this
will result in a SVE access trap on next use of normal SVE, this will cause
us to flush our register state but this is fine since the only way to
trigger a SVE access trap would be to exit streaming mode which will cause
the in register state to be flushed anyway.

Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-1-49df214bfb3e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arm64/ptrace: Flush FP state when setting ZT0 2023-08-11T10:14:23+00:00 Mark Brown broonie@kernel.org 2023-08-03T00:19:06+00:00 0d22576f19038a01572e51b9ebde30dbf1f52b53 commit 89a65c3f170e5c3b05a626046c68354e2afd7912 upstream. When setting ZT0 via ptrace we do not currently force a reload of the floating point register state from memory, do that to ensure that the newly set value gets loaded into the registers on next task execution. The function was templated off the function for FPSIMD which due to our providing the option of embedding a FPSIMD regset within the SVE regset does not directly include the flush. Fixes: f90b529bcbe5 ("arm64/sme: Implement ZT0 ptrace support") Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-zt0-flush-v1-1-72e854eaf96e@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 89a65c3f170e5c3b05a626046c68354e2afd7912 upstream.

When setting ZT0 via ptrace we do not currently force a reload of the
floating point register state from memory, do that to ensure that the newly
set value gets loaded into the registers on next task execution.

The function was templated off the function for FPSIMD which due to our
providing the option of embedding a FPSIMD regset within the SVE regset
does not directly include the flush.

Fixes: f90b529bcbe5 ("arm64/sme: Implement ZT0 ptrace support")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-zt0-flush-v1-1-72e854eaf96e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arm64/fpsimd: Sync FPSIMD state with SVE for SME only systems 2023-08-11T10:14:22+00:00 Mark Brown broonie@kernel.org 2023-08-03T18:33:22+00:00 cfb2b39db5383d1cd269dd140dc2239cb291c726 commit 507ea5dd92d23fcf10e4d1a68a443c86a49753ed upstream. Currently we guard FPSIMD/SVE state conversions with a check for the system supporting SVE but SME only systems may need to sync streaming mode SVE state so add a check for SME support too. These functions are only used by the ptrace code. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-2-49df214bfb3e@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 507ea5dd92d23fcf10e4d1a68a443c86a49753ed upstream.

Currently we guard FPSIMD/SVE state conversions with a check for the system
supporting SVE but SME only systems may need to sync streaming mode SVE
state so add a check for SME support too.  These functions are only used
by the ptrace code.

Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-2-49df214bfb3e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arm64/fpsimd: Clear SME state in the target task when setting the VL 2023-08-11T10:14:22+00:00 Mark Brown broonie@kernel.org 2023-08-02T23:46:39+00:00 789c015d9a18e882993009ac5e1e5f1499895dba commit c9bb40b7f786662e33d71afe236442b0b61f0446 upstream. When setting SME vector lengths we clear TIF_SME to reenable SME traps, doing a reallocation of the backing storage on next use. We do this using clear_thread_flag() which operates on the current thread, meaning that when setting the vector length via ptrace we may both not force traps for the target task and force a spurious flush of any SME state that the tracing task may have. Clear the flag in the target task. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Reported-by: David Spickett <David.Spickett@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-tif-sme-v1-1-88312fd6fbfd@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c9bb40b7f786662e33d71afe236442b0b61f0446 upstream.

When setting SME vector lengths we clear TIF_SME to reenable SME traps,
doing a reallocation of the backing storage on next use. We do this using
clear_thread_flag() which operates on the current thread, meaning that when
setting the vector length via ptrace we may both not force traps for the
target task and force a spurious flush of any SME state that the tracing
task may have.

Clear the flag in the target task.

Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Reported-by: David Spickett <David.Spickett@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-tif-sme-v1-1-88312fd6fbfd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arm64/fpsimd: Sync and zero pad FPSIMD state for streaming SVE 2023-08-11T10:14:22+00:00 Mark Brown broonie@kernel.org 2023-08-03T18:33:23+00:00 0693012274fd01f35981e943e13ef712a09f4abc commit 69af56ae56a48a2522aad906c4461c6c7c092737 upstream. We have a function sve_sync_from_fpsimd_zeropad() which is used by the ptrace code to update the SVE state when the user writes to the the FPSIMD register set. Currently this checks that the task has SVE enabled but this will miss updates for tasks which have streaming SVE enabled if SVE has not been enabled for the thread, also do the conversion if the task has streaming SVE enabled. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-3-49df214bfb3e@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 69af56ae56a48a2522aad906c4461c6c7c092737 upstream.

We have a function sve_sync_from_fpsimd_zeropad() which is used by the
ptrace code to update the SVE state when the user writes to the the
FPSIMD register set.  Currently this checks that the task has SVE
enabled but this will miss updates for tasks which have streaming SVE
enabled if SVE has not been enabled for the thread, also do the
conversion if the task has streaming SVE enabled.

Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-ssve-no-sve-v1-3-49df214bfb3e@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parisc/mm: preallocate fixmap page tables at init 2023-08-11T10:14:22+00:00 Mike Rapoport (IBM) rppt@kernel.org 2023-08-03T06:24:04+00:00 434ebb3960b7f4a013f02422b2677b042f58ed52 commit c2ff2b736c41cc63bb0aaec85cccfead9fbcfe92 upstream. Christoph Biedl reported early OOM on recent kernels: swapper: page allocation failure: order:0, mode:0x100(__GFP_ZERO), nodemask=(null) CPU: 0 PID: 0 Comm: swapper Not tainted 6.3.0-rc4+ #16 Hardware name: 9000/785/C3600 Backtrace: [<10408594>] show_stack+0x48/0x5c [<10e152d8>] dump_stack_lvl+0x48/0x64 [<10e15318>] dump_stack+0x24/0x34 [<105cf7f8>] warn_alloc+0x10c/0x1c8 [<105d068c>] __alloc_pages+0xbbc/0xcf8 [<105d0e4c>] __get_free_pages+0x28/0x78 [<105ad10c>] __pte_alloc_kernel+0x30/0x98 [<10406934>] set_fixmap+0xec/0xf4 [<10411ad4>] patch_map.constprop.0+0xa8/0xdc [<10411bb0>] __patch_text_multiple+0xa8/0x208 [<10411d78>] patch_text+0x30/0x48 [<1041246c>] arch_jump_label_transform+0x90/0xcc [<1056f734>] jump_label_update+0xd4/0x184 [<1056fc9c>] static_key_enable_cpuslocked+0xc0/0x110 [<1056fd08>] static_key_enable+0x1c/0x2c [<1011362c>] init_mem_debugging_and_hardening+0xdc/0xf8 [<1010141c>] start_kernel+0x5f0/0xa98 [<10105da8>] start_parisc+0xb8/0xe4 Mem-Info: active_anon:0 inactive_anon:0 isolated_anon:0 active_file:0 inactive_file:0 isolated_file:0 unevictable:0 dirty:0 writeback:0 slab_reclaimable:0 slab_unreclaimable:0 mapped:0 shmem:0 pagetables:0 sec_pagetables:0 bounce:0 kernel_misc_reclaimable:0 free:0 free_pcp:0 free_cma:0 Node 0 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB +writeback_tmp:0kB kernel_stack:0kB pagetables:0kB sec_pagetables:0kB all_unreclaimable? no Normal free:0kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB +present:1048576kB managed:1039360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 0 Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB 0 total pagecache pages 0 pages in swap cache Free swap = 0kB Total swap = 0kB 262144 pages RAM 0 pages HighMem/MovableOnly 2304 pages reserved Backtrace: [<10411d78>] patch_text+0x30/0x48 [<1041246c>] arch_jump_label_transform+0x90/0xcc [<1056f734>] jump_label_update+0xd4/0x184 [<1056fc9c>] static_key_enable_cpuslocked+0xc0/0x110 [<1056fd08>] static_key_enable+0x1c/0x2c [<1011362c>] init_mem_debugging_and_hardening+0xdc/0xf8 [<1010141c>] start_kernel+0x5f0/0xa98 [<10105da8>] start_parisc+0xb8/0xe4 Kernel Fault: Code=15 (Data TLB miss fault) at addr 0f7fe3c0 CPU: 0 PID: 0 Comm: swapper Not tainted 6.3.0-rc4+ #16 Hardware name: 9000/785/C3600 This happens because patching static key code temporarily maps it via fixmap and if it happens before page allocator is initialized set_fixmap() cannot allocate memory using pte_alloc_kernel(). Make sure that fixmap page tables are preallocated early so that pte_offset_kernel() in set_fixmap() never resorts to pte allocation. Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Helge Deller <deller@gmx.de> Tested-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Tested-by: John David Anglin <dave.anglin@bell.net> Cc: <stable@vger.kernel.org> # v6.4+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c2ff2b736c41cc63bb0aaec85cccfead9fbcfe92 upstream.

Christoph Biedl reported early OOM on recent kernels:

    swapper: page allocation failure: order:0, mode:0x100(__GFP_ZERO),
nodemask=(null)
    CPU: 0 PID: 0 Comm: swapper Not tainted 6.3.0-rc4+ #16
    Hardware name: 9000/785/C3600
    Backtrace:
     [<10408594>] show_stack+0x48/0x5c
     [<10e152d8>] dump_stack_lvl+0x48/0x64
     [<10e15318>] dump_stack+0x24/0x34
     [<105cf7f8>] warn_alloc+0x10c/0x1c8
     [<105d068c>] __alloc_pages+0xbbc/0xcf8
     [<105d0e4c>] __get_free_pages+0x28/0x78
     [<105ad10c>] __pte_alloc_kernel+0x30/0x98
     [<10406934>] set_fixmap+0xec/0xf4
     [<10411ad4>] patch_map.constprop.0+0xa8/0xdc
     [<10411bb0>] __patch_text_multiple+0xa8/0x208
     [<10411d78>] patch_text+0x30/0x48
     [<1041246c>] arch_jump_label_transform+0x90/0xcc
     [<1056f734>] jump_label_update+0xd4/0x184
     [<1056fc9c>] static_key_enable_cpuslocked+0xc0/0x110
     [<1056fd08>] static_key_enable+0x1c/0x2c
     [<1011362c>] init_mem_debugging_and_hardening+0xdc/0xf8
     [<1010141c>] start_kernel+0x5f0/0xa98
     [<10105da8>] start_parisc+0xb8/0xe4

    Mem-Info:
    active_anon:0 inactive_anon:0 isolated_anon:0
     active_file:0 inactive_file:0 isolated_file:0
     unevictable:0 dirty:0 writeback:0
     slab_reclaimable:0 slab_unreclaimable:0
     mapped:0 shmem:0 pagetables:0
     sec_pagetables:0 bounce:0
     kernel_misc_reclaimable:0
     free:0 free_pcp:0 free_cma:0
    Node 0 active_anon:0kB inactive_anon:0kB active_file:0kB
inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB
mapped:0kB dirty:0kB writeback:0kB shmem:0kB
+writeback_tmp:0kB kernel_stack:0kB pagetables:0kB sec_pagetables:0kB
all_unreclaimable? no
    Normal free:0kB boost:0kB min:0kB low:0kB high:0kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB
inactive_file:0kB unevictable:0kB writepending:0kB
+present:1048576kB managed:1039360kB mlocked:0kB bounce:0kB free_pcp:0kB
local_pcp:0kB free_cma:0kB
    lowmem_reserve[]: 0 0
    Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB
0*1024kB 0*2048kB 0*4096kB = 0kB
    0 total pagecache pages
    0 pages in swap cache
    Free swap  = 0kB
    Total swap = 0kB
    262144 pages RAM
    0 pages HighMem/MovableOnly
    2304 pages reserved
    Backtrace:
     [<10411d78>] patch_text+0x30/0x48
     [<1041246c>] arch_jump_label_transform+0x90/0xcc
     [<1056f734>] jump_label_update+0xd4/0x184
     [<1056fc9c>] static_key_enable_cpuslocked+0xc0/0x110
     [<1056fd08>] static_key_enable+0x1c/0x2c
     [<1011362c>] init_mem_debugging_and_hardening+0xdc/0xf8
     [<1010141c>] start_kernel+0x5f0/0xa98
     [<10105da8>] start_parisc+0xb8/0xe4

    Kernel Fault: Code=15 (Data TLB miss fault) at addr 0f7fe3c0
    CPU: 0 PID: 0 Comm: swapper Not tainted 6.3.0-rc4+ #16
    Hardware name: 9000/785/C3600

This happens because patching static key code temporarily maps it via
fixmap and if it happens before page allocator is initialized set_fixmap()
cannot allocate memory using pte_alloc_kernel().

Make sure that fixmap page tables are preallocated early so that
pte_offset_kernel() in set_fixmap() never resorts to pte allocation.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Helge Deller <deller@gmx.de>
Tested-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Tested-by: John David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # v6.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
powerpc/ftrace: Create a dummy stackframe to fix stack unwind 2023-08-11T10:14:22+00:00 Naveen N Rao naveen@kernel.org 2023-06-21T05:13:49+00:00 410b0d2d54e69d7d23c2fead6d3f45c96e57be8e commit 41a506ef71eb38d94fe133f565c87c3e06ccc072 upstream. With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable@vger.kernel.org Signed-off-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 41a506ef71eb38d94fe133f565c87c3e06ccc072 upstream.

With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to
call into ftrace are emitted right at function entry. The instruction
sequence used is minimal to reduce overhead. Crucially, a stackframe is
not created for the function being traced. This breaks stack unwinding
since the function being traced does not have a stackframe for itself.
As such, it never shows up in the backtrace:

/sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled
/sys/kernel/debug/tracing # cat stack_trace
        Depth    Size   Location    (17 entries)
        -----    ----   --------
  0)     4144      32   ftrace_call+0x4/0x44
  1)     4112     432   get_page_from_freelist+0x26c/0x1ad0
  2)     3680     496   __alloc_pages+0x290/0x1280
  3)     3184     336   __folio_alloc+0x34/0x90
  4)     2848     176   vma_alloc_folio+0xd8/0x540
  5)     2672     272   __handle_mm_fault+0x700/0x1cc0
  6)     2400     208   handle_mm_fault+0xf0/0x3f0
  7)     2192      80   ___do_page_fault+0x3e4/0xbe0
  8)     2112     160   do_page_fault+0x30/0xc0
  9)     1952     256   data_access_common_virt+0x210/0x220
 10)     1696     400   0xc00000000f16b100
 11)     1296     384   load_elf_binary+0x804/0x1b80
 12)      912     208   bprm_execve+0x2d8/0x7e0
 13)      704      64   do_execveat_common+0x1d0/0x2f0
 14)      640     160   sys_execve+0x54/0x70
 15)      480      64   system_call_exception+0x138/0x350
 16)      416     416   system_call_common+0x160/0x2c4

Fix this by having ftrace create a dummy stackframe for the function
being traced. With this, backtraces now capture the function being
traced:

/sys/kernel/debug/tracing # cat stack_trace
        Depth    Size   Location    (17 entries)
        -----    ----   --------
  0)     3888      32   _raw_spin_trylock+0x8/0x70
  1)     3856     576   get_page_from_freelist+0x26c/0x1ad0
  2)     3280      64   __alloc_pages+0x290/0x1280
  3)     3216     336   __folio_alloc+0x34/0x90
  4)     2880     176   vma_alloc_folio+0xd8/0x540
  5)     2704     416   __handle_mm_fault+0x700/0x1cc0
  6)     2288      96   handle_mm_fault+0xf0/0x3f0
  7)     2192      48   ___do_page_fault+0x3e4/0xbe0
  8)     2144     192   do_page_fault+0x30/0xc0
  9)     1952     608   data_access_common_virt+0x210/0x220
 10)     1344      16   0xc0000000334bbb50
 11)     1328     416   load_elf_binary+0x804/0x1b80
 12)      912      64   bprm_execve+0x2d8/0x7e0
 13)      848     176   do_execveat_common+0x1d0/0x2f0
 14)      672     192   sys_execve+0x54/0x70
 15)      480      64   system_call_exception+0x138/0x350
 16)      416     416   system_call_common+0x160/0x2c4

This results in two additional stores in the ftrace entry code, but
produces reliable backtraces.

Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable@vger.kernel.org
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>