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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS fix from Borislav Petkov:
- Flush out logged errors immediately after MCA banks configuration
changes over sysfs have been done instead of waiting until something
else triggers the workqueue later - another error or the polling
interval cycle is reached
* tag 'ras_urgent_for_v6.3_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Make sure logged MCEs are processed after sysfs update
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
"There's a little bit more 'movement' in there for my taste but it
needs to happen and should make the code better after it.
- Check cmdline_find_option()'s return value before further
processing
- Clear temporary storage in the resctrl code to prevent access to an
unexistent MSR
- Add a simple throttling mechanism to protect the hypervisor from
potentially malicious SEV guests issuing requests in rapid
succession.
In order to not jeopardize the sanity of everyone involved in
maintaining this code, the request issuing side has received a
cleanup, split in more or less trivial, small and digestible
pieces. Otherwise, the code was threatening to become an
unmaintainable mess.
Therefore, that cleanup is marked indirectly also for stable so
that there's no differences between the upstream code and the
stable variant when it comes down to backporting more there"
* tag 'x86_urgent_for_v6.3_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Fix use of uninitialized buffer in sme_enable()
x86/resctrl: Clear staged_config[] before and after it is used
virt/coco/sev-guest: Add throttling awareness
virt/coco/sev-guest: Convert the sw_exit_info_2 checking to a switch-case
virt/coco/sev-guest: Do some code style cleanups
virt/coco/sev-guest: Carve out the request issuing logic into a helper
virt/coco/sev-guest: Remove the disable_vmpck label in handle_guest_request()
virt/coco/sev-guest: Simplify extended guest request handling
virt/coco/sev-guest: Check SEV_SNP attribute at probe time
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
- cleanup for xen time handling
- enable the VGA console in a Xen PVH dom0
- cleanup in the xenfs driver
* tag 'for-linus-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: remove unnecessary (void*) conversions
x86/PVH: obtain VGA console info in Dom0
x86/xen/time: cleanup xen_tsc_safe_clocksource
xen: update arch/x86/include/asm/xen/cpuid.h
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- fixes to the ASID allocator to avoid leaking stale mappings between
tasks
- fix the vmalloc fault handler to tolerate huge pages
* tag 'riscv-for-linus-6.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: mm: Support huge page in vmalloc_fault()
riscv: asid: Fixup stale TLB entry cause application crash
Revert "riscv: mm: notify remote harts about mmu cache updates"
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Vasily Gorbik:
- Update defconfigs
- Fix early boot code by adding missing intersection check to prevent
potential overwriting of the ipl report
- Fix a use-after-free issue in s390-specific code related to PCI
resources being retained after hot-unplugging individual functions,
by removing the resources from the PCI bus's resource list and using
the zpci_bar_struct's resource pointer directly
* tag 's390-6.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: update defconfigs
PCI: s390: Fix use-after-free of PCI resources with per-function hotplug
s390/ipl: add missing intersection check to ipl_report handling
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- Fix false detection of read faults, introduced by execute-only
support
- Fix a build failure when GENERIC_ALLOCATOR is not selected
Thanks to Russell Currey, Randy Dunlap, Michal Suchánek, Nathan Lynch,
and Benjamin Gray.
* tag 'powerpc-6.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/mm: Fix false detection of read faults
powerpc/pseries: RTAS work area requires GENERIC_ALLOCATOR
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Pull kvm fixes from Paolo Bonzini:
"ARM64:
- Address a rather annoying bug w.r.t. guest timer offsetting. The
synchronization of timer offsets between vCPUs was broken, leading
to inconsistent timer reads within the VM.
x86:
- New tests for the slow path of the EVTCHNOP_send Xen hypercall
- Add missing nVMX consistency checks for CR0 and CR4
- Fix bug that broke AMD GATag on 512 vCPU machines
Selftests:
- Skip hugetlb tests if huge pages are not available
- Sync KVM exit reasons"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: selftests: Sync KVM exit reasons in selftests
KVM: selftests: Add macro to generate KVM exit reason strings
KVM: selftests: Print expected and actual exit reason in KVM exit reason assert
KVM: selftests: Make vCPU exit reason test assertion common
KVM: selftests: Add EVTCHNOP_send slow path test to xen_shinfo_test
KVM: selftests: Use enum for test numbers in xen_shinfo_test
KVM: selftests: Add helpers to make Xen-style VMCALL/VMMCALL hypercalls
KVM: selftests: Move the guts of kvm_hypercall() to a separate macro
KVM: SVM: WARN if GATag generation drops VM or vCPU ID information
KVM: SVM: Modify AVIC GATag to support max number of 512 vCPUs
KVM: SVM: Fix a benign off-by-one bug in AVIC physical table mask
selftests: KVM: skip hugetlb tests if huge pages are not available
KVM: VMX: Use tabs instead of spaces for indentation
KVM: VMX: Fix indentation coding style issue
KVM: nVMX: remove unnecessary #ifdef
KVM: nVMX: add missing consistency checks for CR0 and CR4
KVM: arm64: timers: Convert per-vcpu virtual offset to a global value
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cmdline_find_option() may fail before doing any initialization of
the buffer array. This may lead to unpredictable results when the same
buffer is used later in calls to strncmp() function. Fix the issue by
returning early if cmdline_find_option() returns an error.
Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.
Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230306160656.14844-1-n.zhandarovich@fintech.ru
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As a temporary storage, staged_config[] in rdt_domain should be cleared
before and after it is used. The stale value in staged_config[] could
cause an MSR access error.
Here is a reproducer on a system with 16 usable CLOSIDs for a 15-way L3
Cache (MBA should be disabled if the number of CLOSIDs for MB is less than
16.) :
mount -t resctrl resctrl -o cdp /sys/fs/resctrl
mkdir /sys/fs/resctrl/p{1..7}
umount /sys/fs/resctrl/
mount -t resctrl resctrl /sys/fs/resctrl
mkdir /sys/fs/resctrl/p{1..8}
An error occurs when creating resource group named p8:
unchecked MSR access error: WRMSR to 0xca0 (tried to write 0x00000000000007ff) at rIP: 0xffffffff82249142 (cat_wrmsr+0x32/0x60)
Call Trace:
<IRQ>
__flush_smp_call_function_queue+0x11d/0x170
__sysvec_call_function+0x24/0xd0
sysvec_call_function+0x89/0xc0
</IRQ>
<TASK>
asm_sysvec_call_function+0x16/0x20
When creating a new resource control group, hardware will be configured
by the following process:
rdtgroup_mkdir()
rdtgroup_mkdir_ctrl_mon()
rdtgroup_init_alloc()
resctrl_arch_update_domains()
resctrl_arch_update_domains() iterates and updates all resctrl_conf_type
whose have_new_ctrl is true. Since staged_config[] holds the same values as
when CDP was enabled, it will continue to update the CDP_CODE and CDP_DATA
configurations. When group p8 is created, get_config_index() called in
resctrl_arch_update_domains() will return 16 and 17 as the CLOSIDs for
CDP_CODE and CDP_DATA, which will be translated to an invalid register -
0xca0 in this scenario.
Fix it by clearing staged_config[] before and after it is used.
[reinette: re-order commit tags]
Fixes: 75408e43509e ("x86/resctrl: Allow different CODE/DATA configurations to be staged")
Suggested-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Shawn Wang <shawnwang@linux.alibaba.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/2fad13f49fbe89687fc40e9a5a61f23a28d1507a.1673988935.git.reinette.chatre%40intel.com
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To support detection of read faults with Radix execute-only memory, the
vma_is_accessible() check in access_error() (which checks for PROT_NONE)
was replaced with a check to see if VM_READ was missing, and if so,
returns true to assert the fault was caused by a bad read.
This is incorrect, as it ignores that both VM_WRITE and VM_EXEC imply
read on powerpc, as defined in protection_map[]. This causes mappings
containing VM_WRITE or VM_EXEC without VM_READ to misreport the cause of
page faults, since the MMU is still allowing reads.
Correct this by restoring the original vma_is_accessible() check for
PROT_NONE mappings, and adding a separate check for Radix PROT_EXEC-only
mappings.
Fixes: 395cac7752b9 ("powerpc/mm: Support execute-only memory on the Radix MMU")
Reported-by: Michal Suchánek <msuchanek@suse.de>
Link: https://lore.kernel.org/r/20230308152702.GR19419@kitsune.suse.cz
Tested-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230310050834.63105-1-ruscur@russell.cc
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Since RISC-V supports ioremap() with huge page (pud/pmd) mapping,
However, vmalloc_fault() assumes that the vmalloc range is limited
to pte mappings. To complete the vmalloc_fault() function by adding
huge page support.
Fixes: 310f541a027b ("riscv: Enable HAVE_ARCH_HUGE_VMAP for 64BIT")
Cc: stable@vger.kernel.org
Signed-off-by: Dylan Jhong <dylan@andestech.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230310075021.3919290-1-dylan@andestech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Do not allow histogram values to have modifies. They can cause a NULL
pointer dereference if they do.
- Warn if hist_field_name() is passed a NULL. Prevent the NULL pointer
dereference mentioned above.
- Fix invalid address look up race in lookup_rec()
- Define ftrace_stub_graph conditionally to prevent linker errors
- Always check if RCU is watching at all tracepoint locations
* tag 'trace-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Make tracepoint lockdep check actually test something
ftrace,kcfi: Define ftrace_stub_graph conditionally
ftrace: Fix invalid address access in lookup_rec() when index is 0
tracing: Check field value in hist_field_name()
tracing: Do not let histogram values have some modifiers
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A new platform-op was added to Xen to allow obtaining the same VGA
console information PV Dom0 is handed. Invoke the new function and have
the output data processed by xen_init_vga().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/8f315e92-7bda-c124-71cc-478ab9c5e610@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
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WARN if generating a GATag given a VM ID and vCPU ID doesn't yield the
same IDs when pulling the IDs back out of the tag. Don't bother adding
error handling to callers, this is very much a paranoid sanity check as
KVM fully controls the VM ID and is supposed to reject too-big vCPU IDs.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-Id: <20230207002156.521736-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Define AVIC_VCPU_ID_MASK based on AVIC_PHYSICAL_MAX_INDEX, i.e. the mask
that effectively controls the largest guest physical APIC ID supported by
x2AVIC, instead of hardcoding the number of bits to 8 (and the number of
VM bits to 24).
The AVIC GATag is programmed into the AMD IOMMU IRTE to provide a
reference back to KVM in case the IOMMU cannot inject an interrupt into a
non-running vCPU. In such a case, the IOMMU notifies software by creating
a GALog entry with the corresponded GATag, and KVM then uses the GATag to
find the correct VM+vCPU to kick. Dropping bit 8 from the GATag results
in kicking the wrong vCPU when targeting vCPUs with x2APIC ID > 255.
Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode")
Cc: stable@vger.kernel.org
Reported-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-Id: <20230207002156.521736-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Define the "physical table max index mask" as bits 8:0, not 9:0. x2AVIC
currently supports a max of 512 entries, i.e. the max index is 511, and
the inputs to GENMASK_ULL() are inclusive. The bug is benign as bit 9 is
reserved and never set by KVM, i.e. KVM is just clearing bits that are
guaranteed to be zero.
Note, as of this writing, APM "Rev. 3.39-October 2022" incorrectly states
that bits 11:8 are reserved in Table B-1. VMCB Layout, Control Area. I.e.
that table wasn't updated when x2AVIC support was added.
Opportunistically fix the comment for the max AVIC ID to align with the
code, and clean up comment formatting too.
Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode")
Cc: stable@vger.kernel.org
Cc: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-Id: <20230207002156.521736-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Code indentation should use tabs where possible and miss a '*'.
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Message-Id: <tencent_A492CB3F9592578451154442830EA1B02C07@qq.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Code indentation should use tabs where possible.
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Message-Id: <tencent_31E6ACADCB6915E157CF5113C41803212107@qq.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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nested_vmx_check_controls() has already run by the time KVM checks host state,
so the "host address space size" exit control can only be set on x86-64 hosts.
Simplify the condition at the cost of adding some dead code to 32-bit kernels.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The effective values of the guest CR0 and CR4 registers may differ from
those included in the VMCS12. In particular, disabling EPT forces
CR4.PAE=1 and disabling unrestricted guest mode forces CR0.PG=CR0.PE=1.
Therefore, checks on these bits cannot be delegated to the processor
and must be performed by KVM.
Reported-by: Reima ISHII <ishiir@g.ecc.u-tokyo.ac.jp>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for 6.3, part #1
A single patch to address a rather annoying bug w.r.t. guest timer
offsetting. Effectively the synchronization of timer offsets between
vCPUs was broken, leading to inconsistent timer reads within the VM.
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The RTAS work area allocator uses code that is built by
GENERIC_ALLOCATOR, so the PSERIES Kconfig should select the
required Kconfig symbol to fix multiple build errors.
powerpc64-linux-ld: arch/powerpc/platforms/pseries/rtas-work-area.o: in function `.rtas_work_area_allocator_init':
rtas-work-area.c:(.init.text+0x288): undefined reference to `.gen_pool_create'
powerpc64-linux-ld: rtas-work-area.c:(.init.text+0x2dc): undefined reference to `.gen_pool_set_algo'
powerpc64-linux-ld: rtas-work-area.c:(.init.text+0x310): undefined reference to `.gen_pool_add_owner'
powerpc64-linux-ld: rtas-work-area.c:(.init.text+0x43c): undefined reference to `.gen_pool_destroy'
powerpc64-linux-ld: arch/powerpc/platforms/pseries/rtas-work-area.o:(.toc+0x0): undefined reference to `gen_pool_first_fit_order_align'
powerpc64-linux-ld: arch/powerpc/platforms/pseries/rtas-work-area.o: in function `.__rtas_work_area_alloc':
rtas-work-area.c:(.ref.text+0x14c): undefined reference to `.gen_pool_alloc_algo_owner'
powerpc64-linux-ld: rtas-work-area.c:(.ref.text+0x238): undefined reference to `.gen_pool_alloc_algo_owner'
powerpc64-linux-ld: arch/powerpc/platforms/pseries/rtas-work-area.o: in function `.rtas_work_area_free':
rtas-work-area.c:(.ref.text+0x44c): undefined reference to `.gen_pool_free_owner'
Fixes: 43033bc62d34 ("powerpc/pseries: add RTAS work area allocator")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230223070116.660-2-rdunlap@infradead.org
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A potentially malicious SEV guest can constantly hammer the hypervisor
using this driver to send down requests and thus prevent or at least
considerably hinder other guests from issuing requests to the secure
processor which is a shared platform resource.
Therefore, the host is permitted and encouraged to throttle such guest
requests.
Add the capability to handle the case when the hypervisor throttles
excessive numbers of requests issued by the guest. Otherwise, the VM
platform communication key will be disabled, preventing the guest from
attesting itself.
Realistically speaking, a well-behaved guest should not even care about
throttling. During its lifetime, it would end up issuing a handful of
requests which the hardware can easily handle.
This is more to address the case of a malicious guest. Such guest should
get throttled and if its VMPCK gets disabled, then that's its own
wrongdoing and perhaps that guest even deserves it.
To the implementation: the hypervisor signals with SNP_GUEST_REQ_ERR_BUSY
that the guest requests should be throttled. That error code is returned
in the upper 32-bit half of exitinfo2 and this is part of the GHCB spec
v2.
So the guest is given a throttling period of 1 minute in which it
retries the request every 2 seconds. This is a good default but if it
turns out to not pan out in practice, it can be tweaked later.
For safety, since the encryption algorithm in GHCBv2 is AES_GCM, control
must remain in the kernel to complete the request with the current
sequence number. Returning without finishing the request allows the
guest to make another request but with different message contents. This
is IV reuse, and breaks cryptographic protections.
[ bp:
- Rewrite commit message and do a simplified version.
- The stable tags are supposed to denote that a cleanup should go
upfront before backporting this so that any future fixes to this
can preserve the sanity of the backporter(s). ]
Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs")
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org> # d6fd48eff750 ("virt/coco/sev-guest: Check SEV_SNP attribute at probe time")
Cc: <stable@kernel.org> # 970ab823743f (" virt/coco/sev-guest: Simplify extended guest request handling")
Cc: <stable@kernel.org> # c5a338274bdb ("virt/coco/sev-guest: Remove the disable_vmpck label in handle_guest_request()")
Cc: <stable@kernel.org> # 0fdb6cc7c89c ("virt/coco/sev-guest: Carve out the request issuing logic into a helper")
Cc: <stable@kernel.org> # d25bae7dc7b0 ("virt/coco/sev-guest: Do some code style cleanups")
Cc: <stable@kernel.org> # fa4ae42cc60a ("virt/coco/sev-guest: Convert the sw_exit_info_2 checking to a switch-case")
Link: https://lore.kernel.org/r/20230214164638.1189804-2-dionnaglaze@google.com
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snp_issue_guest_request() checks the value returned by the hypervisor in
sw_exit_info_2 and returns a different error depending on it.
Convert those checks into a switch-case to make it more readable when
more error values are going to be checked in the future.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230307192449.24732-8-bp@alien8.de
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Return a specific error code - -ENOSPC - to signal the too small cert
data buffer instead of checking exit code and exitinfo2.
While at it, hoist the *fw_err assignment in snp_issue_guest_request()
so that a proper error value is returned to the callers.
[ Tom: check override_err instead of err. ]
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230307192449.24732-4-bp@alien8.de
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No need to check it on every ioctl. And yes, this is a common SEV driver
but it does only SNP-specific operations currently. This can be
revisited later, when more use cases appear.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230307192449.24732-3-bp@alien8.de
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Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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On s390 PCI functions may be hotplugged individually even when they
belong to a multi-function device. In particular on an SR-IOV device VFs
may be removed and later re-added.
In commit a50297cf8235 ("s390/pci: separate zbus creation from
scanning") it was missed however that struct pci_bus and struct
zpci_bus's resource list retained a reference to the PCI functions MMIO
resources even though those resources are released and freed on
hot-unplug. These stale resources may subsequently be claimed when the
PCI function re-appears resulting in use-after-free.
One idea of fixing this use-after-free in s390 specific code that was
investigated was to simply keep resources around from the moment a PCI
function first appeared until the whole virtual PCI bus created for
a multi-function device disappears. The problem with this however is
that due to the requirement of artificial MMIO addreesses (address
cookies) extra logic is then needed to keep the address cookies
compatible on re-plug. At the same time the MMIO resources semantically
belong to the PCI function so tying their lifecycle to the function
seems more logical.
Instead a simpler approach is to remove the resources of an individually
hot-unplugged PCI function from the PCI bus's resource list while
keeping the resources of other PCI functions on the PCI bus untouched.
This is done by introducing pci_bus_remove_resource() to remove an
individual resource. Similarly the resource also needs to be removed
from the struct zpci_bus's resource list. It turns out however, that
there is really no need to add the MMIO resources to the struct
zpci_bus's resource list at all and instead we can simply use the
zpci_bar_struct's resource pointer directly.
Fixes: a50297cf8235 ("s390/pci: separate zbus creation from scanning")
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20230306151014.60913-2-schnelle@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
|
|
The code which handles the ipl report is searching for a free location
in memory where it could copy the component and certificate entries to.
It checks for intersection between the sections required for the kernel
and the component/certificate data area, but fails to check whether
the data structures linking these data areas together intersect.
This might cause the iplreport copy code to overwrite the iplreport
itself. Fix this by adding two addtional intersection checks.
Cc: <stable@vger.kernel.org>
Fixes: 9641b8cc733f ("s390/ipl: read IPL report at early boot")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
|
|
A recent change introduced a flag to queue up errors found during
boot-time polling. These errors will be processed during late init once
the MCE subsystem is fully set up.
A number of sysfs updates call mce_restart() which goes through a subset
of the CPU init flow. This includes polling MCA banks and logging any
errors found. Since the same function is used as boot-time polling,
errors will be queued. However, the system is now past late init, so the
errors will remain queued until another error is found and the workqueue
is triggered.
Call mce_schedule_work() at the end of mce_restart() so that queued
errors are processed.
Fixes: 3bff147b187d ("x86/mce: Defer processing of early errors")
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230301221420.2203184-1-yazen.ghannam@amd.com
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
"A single erratum fix for AMD machines:
- Disable XSAVES on AMD Zen1 and Zen2 machines due to an erratum. No
impact to anything as those machines will fallback to XSAVEC which
is equivalent there"
* tag 'x86_urgent_for_v6.3_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/CPU/AMD: Disable XSAVES on AMD family 0x17
|
|
Having a per-vcpu virtual offset is a pain. It needs to be synchronized
on each update, and expands badly to a setup where different timers can
have different offsets, or have composite offsets (as with NV).
So let's start by replacing the use of the CNTVOFF_EL2 shadow register
(which we want to reclaim for NV anyway), and make the virtual timer
carry a pointer to a VM-wide offset.
This simplifies the code significantly. It also addresses two terrible bugs:
- The use of CNTVOFF_EL2 leads to some nice offset corruption
when the sysreg gets reset, as reported by Joey.
- The kvm mutex is taken from a vcpu ioctl, which goes against
the locking rules...
Reported-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230224173915.GA17407@e124191.cambridge.arm.com
Tested-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20230224191640.3396734-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
|
|
Pull misc fixes from Al Viro:
"pick_file() speculation fix + fix for alpha mis(merge,cherry-pick)
The fs/file.c one is a genuine missing speculation barrier in
pick_file() (reachable e.g. via close(2)). The alpha one is strictly
speaking not a bug fix, but only because confusion between
preempt_enable() and preempt_disable() is harmless on architecture
without CONFIG_PREEMPT.
Looks like alpha.git picked the wrong version of patch - that braino
used to be there in early versions, but it had been fixed quite a
while ago..."
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: prevent out-of-bounds array speculation when closing a file descriptor
alpha: fix lazy-FPU mis(merged/applied/whatnot)
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- RISC-V architecture-specific ELF attributes have been disabled in the
kernel builds
- A fix for a locking failure while during errata patching that
manifests on SiFive-based systems
- A fix for a KASAN failure during stack unwinding
- A fix for some lockdep failures during text patching
* tag 'riscv-for-linus-6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: Don't check text_mutex during stop_machine
riscv: Use READ_ONCE_NOCHECK in imprecise unwinding stack mode
RISC-V: fix taking the text_mutex twice during sifive errata patching
RISC-V: Stop emitting attributes
|
|
When CONFIG_FUNCTION_GRAPH_TRACER is disabled, __kcfi_typeid_ftrace_stub_graph
is missing, causing a link failure:
ld.lld: error: undefined symbol: __kcfi_typeid_ftrace_stub_graph
referenced by arch/x86/kernel/ftrace_64.o:(__cfi_ftrace_stub_graph) in archive vmlinux.a
Mark the reference to it as conditional on the same symbol, as
is done on arm64.
Link: https://lore.kernel.org/linux-trace-kernel/20230131093643.3850272-1-arnd@kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Fixes: 883bbbffa5a4 ("ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()")
See-also: 2598ac6ec493 ("arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
entries"
Sergey Matyukevich <geomatsi@gmail.com> says:
Some time ago two different patches have been posted to fix stale TLB
entries that caused applications crashes.
The patch [0] suggested 'aggregating' mm_cpumask, i.e. current cpu is not
cleared for the switched-out task in switch_mm function. For additional
explanations see the commit message by Guo Ren. The same approach is
used by arc architecture, so another good comment is for switch_mm
in arch/arc/include/asm/mmu_context.h.
The patch [1] attempted to reduce the number of TLB flushes by deferring
(and possibly avoiding) them for CPUs not running the task.
Patch [1] has been merged. However we already have two bug reports from
different vendors. So apparently something is missing in the approach
suggested in [1]. In both cases the patch [0] fixed the issue.
This patch series reverts [1] and replaces it by [0].
[0] https://lore.kernel.org/linux-riscv/20221111075902.798571-1-guoren@kernel.org/
[1] https://lore.kernel.org/linux-riscv/20220829205219.283543-1-geomatsi@gmail.com/
* b4-shazam-merge:
riscv: asid: Fixup stale TLB entry cause application crash
Revert "riscv: mm: notify remote harts about mmu cache updates"
Link: https://lore.kernel.org/r/20230226150137.1919750-1-geomatsi@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
After use_asid_allocator is enabled, the userspace application will
crash by stale TLB entries. Because only using cpumask_clear_cpu without
local_flush_tlb_all couldn't guarantee CPU's TLB entries were fresh.
Then set_mm_asid would cause the user space application to get a stale
value by stale TLB entry, but set_mm_noasid is okay.
Here is the symptom of the bug:
unhandled signal 11 code 0x1 (coredump)
0x0000003fd6d22524 <+4>: auipc s0,0x70
0x0000003fd6d22528 <+8>: ld s0,-148(s0) # 0x3fd6d92490
=> 0x0000003fd6d2252c <+12>: ld a5,0(s0)
(gdb) i r s0
s0 0x8082ed1cc3198b21 0x8082ed1cc3198b21
(gdb) x /2x 0x3fd6d92490
0x3fd6d92490: 0xd80ac8a8 0x0000003f
The core dump file shows that register s0 is wrong, but the value in
memory is correct. Because 'ld s0, -148(s0)' used a stale mapping entry
in TLB and got a wrong result from an incorrect physical address.
When the task ran on CPU0, which loaded/speculative-loaded the value of
address(0x3fd6d92490), then the first version of the mapping entry was
PTWed into CPU0's TLB.
When the task switched from CPU0 to CPU1 (No local_tlb_flush_all here by
asid), it happened to write a value on the address (0x3fd6d92490). It
caused do_page_fault -> wp_page_copy -> ptep_clear_flush ->
ptep_get_and_clear & flush_tlb_page.
The flush_tlb_page used mm_cpumask(mm) to determine which CPUs need TLB
flush, but CPU0 had cleared the CPU0's mm_cpumask in the previous
switch_mm. So we only flushed the CPU1 TLB and set the second version
mapping of the PTE. When the task switched from CPU1 to CPU0 again, CPU0
still used a stale TLB mapping entry which contained a wrong target
physical address. It raised a bug when the task happened to read that
value.
CPU0 CPU1
- switch 'task' in
- read addr (Fill stale mapping
entry into TLB)
- switch 'task' out (no tlb_flush)
- switch 'task' in (no tlb_flush)
- write addr cause pagefault
do_page_fault() (change to
new addr mapping)
wp_page_copy()
ptep_clear_flush()
ptep_get_and_clear()
& flush_tlb_page()
write new value into addr
- switch 'task' out (no tlb_flush)
- switch 'task' in (no tlb_flush)
- read addr again (Use stale
mapping entry in TLB)
get wrong value from old phyical
addr, BUG!
The solution is to keep all CPUs' footmarks of cpumask(mm) in switch_mm,
which could guarantee to invalidate all stale TLB entries during TLB
flush.
Fixes: 65d4b9c53017 ("RISC-V: Implement ASID allocator")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: Zong Li <zong.li@sifive.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com>
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230226150137.1919750-3-geomatsi@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
This reverts the remaining bits of commit 4bd1d80efb5a ("riscv: mm:
notify remote harts harts about mmu cache updates").
According to bug reports, suggested approach to fix stale TLB entries
is not sufficient. It needs to be replaced by a more robust solution.
Fixes: 4bd1d80efb5a ("riscv: mm: notify remote harts about mmu cache updates")
Reported-by: Zong Li <zong.li@sifive.com>
Reported-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com>
Cc: stable@vger.kernel.org
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230226150137.1919750-2-geomatsi@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
We're currently using stop_machine() to update ftrace & kprobes, which
means that the thread that takes text_mutex during may not be the same
as the thread that eventually patches the code. This isn't actually a
race because the lock is still held (preventing any other concurrent
accesses) and there is only one thread running during stop_machine(),
but it does trigger a lockdep failure.
This patch just elides the lockdep check during stop_machine.
Fixes: c15ac4fd60d5 ("riscv/ftrace: Add dynamic function tracer support")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230303143754.4005217-1-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
When CONFIG_FRAME_POINTER is unset, the stack unwinding function
walk_stackframe randomly reads the stack and then, when KASAN is enabled,
it can lead to the following backtrace:
[ 0.000000] ==================================================================
[ 0.000000] BUG: KASAN: stack-out-of-bounds in walk_stackframe+0xa6/0x11a
[ 0.000000] Read of size 8 at addr ffffffff81807c40 by task swapper/0
[ 0.000000]
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.2.0-12919-g24203e6db61f #43
[ 0.000000] Hardware name: riscv-virtio,qemu (DT)
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff80007ba8>] walk_stackframe+0x0/0x11a
[ 0.000000] [<ffffffff80099ecc>] init_param_lock+0x26/0x2a
[ 0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[ 0.000000] [<ffffffff80c49c80>] dump_stack_lvl+0x22/0x36
[ 0.000000] [<ffffffff80c3783e>] print_report+0x198/0x4a8
[ 0.000000] [<ffffffff80099ecc>] init_param_lock+0x26/0x2a
[ 0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[ 0.000000] [<ffffffff8015f68a>] kasan_report+0x9a/0xc8
[ 0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[ 0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[ 0.000000] [<ffffffff8006e99c>] desc_make_final+0x80/0x84
[ 0.000000] [<ffffffff8009a04e>] stack_trace_save+0x88/0xa6
[ 0.000000] [<ffffffff80099fc2>] filter_irq_stacks+0x72/0x76
[ 0.000000] [<ffffffff8006b95e>] devkmsg_read+0x32a/0x32e
[ 0.000000] [<ffffffff8015ec16>] kasan_save_stack+0x28/0x52
[ 0.000000] [<ffffffff8006e998>] desc_make_final+0x7c/0x84
[ 0.000000] [<ffffffff8009a04a>] stack_trace_save+0x84/0xa6
[ 0.000000] [<ffffffff8015ec52>] kasan_set_track+0x12/0x20
[ 0.000000] [<ffffffff8015f22e>] __kasan_slab_alloc+0x58/0x5e
[ 0.000000] [<ffffffff8015e7ea>] __kmem_cache_create+0x21e/0x39a
[ 0.000000] [<ffffffff80e133ac>] create_boot_cache+0x70/0x9c
[ 0.000000] [<ffffffff80e17ab2>] kmem_cache_init+0x6c/0x11e
[ 0.000000] [<ffffffff80e00fd6>] mm_init+0xd8/0xfe
[ 0.000000] [<ffffffff80e011d8>] start_kernel+0x190/0x3ca
[ 0.000000]
[ 0.000000] The buggy address belongs to stack of task swapper/0
[ 0.000000] and is located at offset 0 in frame:
[ 0.000000] stack_trace_save+0x0/0xa6
[ 0.000000]
[ 0.000000] This frame has 1 object:
[ 0.000000] [32, 56) 'c'
[ 0.000000]
[ 0.000000] The buggy address belongs to the physical page:
[ 0.000000] page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x81a07
[ 0.000000] flags: 0x1000(reserved|zone=0)
[ 0.000000] raw: 0000000000001000 ff600003f1e3d150 ff600003f1e3d150 0000000000000000
[ 0.000000] raw: 0000000000000000 0000000000000000 00000001ffffffff
[ 0.000000] page dumped because: kasan: bad access detected
[ 0.000000]
[ 0.000000] Memory state around the buggy address:
[ 0.000000] ffffffff81807b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 0.000000] ffffffff81807b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 0.000000] >ffffffff81807c00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 f3
[ 0.000000] ^
[ 0.000000] ffffffff81807c80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
[ 0.000000] ffffffff81807d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 0.000000] ==================================================================
Fix that by using READ_ONCE_NOCHECK when reading the stack in imprecise
mode.
Fixes: 5d8544e2d007 ("RISC-V: Generic library routines and assembly")
Reported-by: Chathura Rajapaksha <chathura.abeyrathne.lk@gmail.com>
Link: https://lore.kernel.org/all/CAD7mqryDQCYyJ1gAmtMm8SASMWAQ4i103ptTb0f6Oda=tPY2=A@mail.gmail.com/
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230308091639.602024-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Including fixes from netfilter and bpf.
Current release - regressions:
- core: avoid skb end_offset change in __skb_unclone_keeptruesize()
- sched:
- act_connmark: handle errno on tcf_idr_check_alloc
- flower: fix fl_change() error recovery path
- ieee802154: prevent user from crashing the host
Current release - new code bugs:
- eth: bnxt_en: fix the double free during device removal
- tools: ynl:
- fix enum-as-flags in the generic CLI
- fully inherit attrs in subsets
- re-license uniformly under GPL-2.0 or BSD-3-clause
Previous releases - regressions:
- core: use indirect calls helpers for sk_exit_memory_pressure()
- tls:
- fix return value for async crypto
- avoid hanging tasks on the tx_lock
- eth: ice: copy last block omitted in ice_get_module_eeprom()
Previous releases - always broken:
- core: avoid double iput when sock_alloc_file fails
- af_unix: fix struct pid leaks in OOB support
- tls:
- fix possible race condition
- fix device-offloaded sendpage straddling records
- bpf:
- sockmap: fix an infinite loop error
- test_run: fix &xdp_frame misplacement for LIVE_FRAMES
- fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTR
- netfilter: tproxy: fix deadlock due to missing BH disable
- phylib: get rid of unnecessary locking
- eth: bgmac: fix *initial* chip reset to support BCM5358
- eth: nfp: fix csum for ipsec offload
- eth: mtk_eth_soc: fix RX data corruption issue
Misc:
- usb: qmi_wwan: add telit 0x1080 composition"
* tag 'net-6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (64 commits)
tools: ynl: fix enum-as-flags in the generic CLI
tools: ynl: move the enum classes to shared code
net: avoid double iput when sock_alloc_file fails
af_unix: fix struct pid leaks in OOB support
eth: fealnx: bring back this old driver
net: dsa: mt7530: permit port 5 to work without port 6 on MT7621 SoC
net: microchip: sparx5: fix deletion of existing DSCP mappings
octeontx2-af: Unlock contexts in the queue context cache in case of fault detection
net/smc: fix fallback failed while sendmsg with fastopen
ynl: re-license uniformly under GPL-2.0 OR BSD-3-Clause
mailmap: update entries for Stephen Hemminger
mailmap: add entry for Maxim Mikityanskiy
nfc: change order inside nfc_se_io error path
ethernet: ice: avoid gcc-9 integer overflow warning
ice: don't ignore return codes in VSI related code
ice: Fix DSCP PFC TLV creation
net: usb: qmi_wwan: add Telit 0x1080 composition
net: usb: cdc_mbim: avoid altsetting toggling for Telit FE990
netfilter: conntrack: adopt safer max chain length
net: tls: fix device-offloaded sendpage straddling records
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
Pull m68k fixes from Geert Uytterhoeven:
- Fix systems with memory at end of 32-bit address space
- Fix initrd on systems where memory does not start at address zero
- Fix 68030 handling of bus errors for addresses in exception tables
* tag 'm68k-for-v6.3-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k: Only force 030 bus error if PC not in exception table
m68k: mm: Move initrd phys_to_virt handling after paging_init()
m68k: mm: Fix systems with memory at end of 32-bit address space
|
|
We fetch %SR value from sigframe; it might have been modified by signal
handler, so we can't trust it with any bits that are not modifiable in
user mode.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This reverts commit d5e2d038dbece821f1af57acbeded3aa9a1832c1.
We have a report of this chip being used on a
SURECOM EP-320X-S 100/10M Ethernet PCI Adapter
which could still have been purchased in some parts
of the world 3 years ago.
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217151
Fixes: d5e2d038dbec ("eth: fealnx: delete the driver for Myson MTD-800")
Link: https://lore.kernel.org/r/20230307171930.4008454-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
The implementation of 'current' on x86 is very intentionally special: it
is a very common thing to look up, and it uses 'this_cpu_read_stable()'
to get the current thread pointer efficiently from per-cpu storage.
And the keyword in there is 'stable': the current thread pointer never
changes as far as a single thread is concerned. Even if when a thread
is preempted, or moved to another CPU, or even across an explicit call
'schedule()' that thread will still have the same value for 'current'.
It is, after all, the kernel base pointer to thread-local storage.
That's why it's stable to begin with, but it's also why it's important
enough that we have that special 'this_cpu_read_stable()' access for it.
So this is all done very intentionally to allow the compiler to treat
'current' as a value that never visibly changes, so that the compiler
can do CSE and combine multiple different 'current' accesses into one.
However, there is obviously one very special situation when the
currently running thread does actually change: inside the scheduler
itself.
So the scheduler code paths are special, and do not have a 'current'
thread at all. Instead there are _two_ threads: the previous and the
next thread - typically called 'prev' and 'next' (or prev_p/next_p)
internally.
So this is all actually quite straightforward and simple, and not all
that complicated.
Except for when you then have special code that is run in scheduler
context, that code then has to be aware that 'current' isn't really a
valid thing. Did you mean 'prev'? Did you mean 'next'?
In fact, even if then look at the code, and you use 'current' after the
new value has been assigned to the percpu variable, we have explicitly
told the compiler that 'current' is magical and always stable. So the
compiler is quite free to use an older (or newer) value of 'current',
and the actual assignment to the percpu storage is not relevant even if
it might look that way.
Which is exactly what happened in the resctl code, that blithely used
'current' in '__resctrl_sched_in()' when it really wanted the new
process state (as implied by the name: we're scheduling 'into' that new
resctl state). And clang would end up just using the old thread pointer
value at least in some configurations.
This could have happened with gcc too, and purely depends on random
compiler details. Clang just seems to have been more aggressive about
moving the read of the per-cpu current_task pointer around.
The fix is trivial: just make the resctl code adhere to the scheduler
rules of using the prev/next thread pointer explicitly, instead of using
'current' in a situation where it just wasn't valid.
That same code is then also used outside of the scheduler context (when
a thread resctl state is explicitly changed), and then we will just pass
in 'current' as that pointer, of course. There is no ambiguity in that
case.
The fix may be trivial, but noticing and figuring out what went wrong
was not. The credit for that goes to Stephane Eranian.
Reported-by: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/lkml/20230303231133.1486085-1-eranian@google.com/
Link: https://lore.kernel.org/lkml/alpine.LFD.2.01.0908011214330.3304@localhost.localdomain/
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Stephane Eranian <eranian@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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AMD Erratum 1386 is summarised as:
XSAVES Instruction May Fail to Save XMM Registers to the Provided
State Save Area
This piece of accidental chronomancy causes the %xmm registers to
occasionally reset back to an older value.
Ignore the XSAVES feature on all AMD Zen1/2 hardware. The XSAVEC
instruction (which works fine) is equivalent on affected parts.
[ bp: Typos, move it into the F17h-specific function. ]
Reported-by: Tavis Ormandy <taviso@gmail.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230307174643.1240184-1-andrew.cooper3@citrix.com
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Chris pointed out that some bonehead, *cough* me *cough*, added two
mutex_locks() to the SiFive errata patching. The second was meant to
have been a mutex_unlock().
This results in errors such as
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
Oops [#1]
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted
6.2.0-rc1-starlight-00079-g9493e6f3ce02 #229
Hardware name: BeagleV Starlight Beta (DT)
epc : __schedule+0x42/0x500
ra : schedule+0x46/0xce
epc : ffffffff8065957c ra : ffffffff80659a80 sp : ffffffff81203c80
gp : ffffffff812d50a0 tp : ffffffff8120db40 t0 : ffffffff81203d68
t1 : 0000000000000001 t2 : 4c45203a76637369 s0 : ffffffff81203cf0
s1 : ffffffff8120db40 a0 : 0000000000000000 a1 : ffffffff81213958
a2 : ffffffff81213958 a3 : 0000000000000000 a4 : 0000000000000000
a5 : ffffffff80a1bd00 a6 : 0000000000000000 a7 : 0000000052464e43
s2 : ffffffff8120db41 s3 : ffffffff80a1ad00 s4 : 0000000000000000
s5 : 0000000000000002 s6 : ffffffff81213938 s7 : 0000000000000000
s8 : 0000000000000000 s9 : 0000000000000001 s10: ffffffff812d7204
s11: ffffffff80d3c920 t3 : 0000000000000001 t4 : ffffffff812e6dd7
t5 : ffffffff812e6dd8 t6 : ffffffff81203bb8
status: 0000000200000100 badaddr: 0000000000000030 cause: 000000000000000d
[<ffffffff80659a80>] schedule+0x46/0xce
[<ffffffff80659dce>] schedule_preempt_disabled+0x16/0x28
[<ffffffff8065ae0c>] __mutex_lock.constprop.0+0x3fe/0x652
[<ffffffff8065b138>] __mutex_lock_slowpath+0xe/0x16
[<ffffffff8065b182>] mutex_lock+0x42/0x4c
[<ffffffff8000ad94>] sifive_errata_patch_func+0xf6/0x18c
[<ffffffff80002b92>] _apply_alternatives+0x74/0x76
[<ffffffff80802ee8>] apply_boot_alternatives+0x3c/0xfa
[<ffffffff80803cb0>] setup_arch+0x60c/0x640
[<ffffffff80800926>] start_kernel+0x8e/0x99c
---[ end trace 0000000000000000 ]---
Reported-by: Chris Hofstaedtler <zeha@debian.org>
Fixes: 9493e6f3ce02 ("RISC-V: take text_mutex during alternative patching")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230302174154.970746-1-conor@kernel.org
[Palmer: pick up Geert's bug report from the thread]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
pull-request: bpf 2023-03-06
We've added 8 non-merge commits during the last 7 day(s) which contain
a total of 9 files changed, 64 insertions(+), 18 deletions(-).
The main changes are:
1) Fix BTF resolver for DATASEC sections when a VAR points at a modifier,
that is, keep resolving such instances instead of bailing out,
from Lorenz Bauer.
2) Fix BPF test framework with regards to xdp_frame info misplacement
in the "live packet" code, from Alexander Lobakin.
3) Fix an infinite loop in BPF sockmap code for TCP/UDP/AF_UNIX,
from Liu Jian.
4) Fix a build error for riscv BPF JIT under PERF_EVENTS=n,
from Randy Dunlap.
5) Several BPF doc fixes with either broken links or external instead
of internal doc links, from Bagas Sanjaya.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: check that modifier resolves after pointer
btf: fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTR
bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
bpf, doc: Link to submitting-patches.rst for general patch submission info
bpf, doc: Do not link to docs.kernel.org for kselftest link
bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()
riscv, bpf: Fix patch_text implicit declaration
bpf, docs: Fix link to BTF doc
====================
Link: https://lore.kernel.org/r/20230306215944.11981-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Looks like a braino that used to be fixed in e.g. #next.alpha
had gotten into alpha.git cherry-picked version of that patch.
Sure, alpha has no preempt, but preempt_enable() in place of
preempt_disable() is actively confusing the readers...
Other than that, the cherry-picked variant matches what I have.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The RISC-V ELF attributes don't contain any useful information. New
toolchains ignore them, but they frequently trip up various older/mixed
toolchains. So just turn them off.
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230223224605.6995-1-palmer@rivosinc.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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