commit 99c13b8c88 upstream.
The pat_enabled() logic is broken on CPUs which do not support PAT and
where the initialization code fails to call pat_init(). Due to that the
enabled flag stays true and pat_enabled() returns true wrongfully.
As a consequence the mappings, e.g. for Xorg, are set up with the wrong
caching mode and the required MTRR setups are omitted.
To cure this the following changes are required:
1) Make pat_enabled() return true only if PAT initialization was
invoked and successful.
2) Invoke init_cache_modes() unconditionally in setup_arch() and
remove the extra callsites in pat_disable() and the pat disabled
code path in pat_init().
Also rename __pat_enabled to pat_disabled to reflect the real purpose of
this variable.
Fixes: 9cd25aac1f ("x86/mm/pat: Emulate PAT when it is disabled")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Bernhard Held <berny156@gmx.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: "Luis R. Rodriguez" <mcgrof@suse.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1707041749300.3456@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 236222d393 upstream.
According to the Intel datasheet, the REP MOVSB instruction
exposes a pretty heavy setup cost (50 ticks), which hurts
short string copy operations.
This change tries to avoid this cost by calling the explicit
loop available in the unrolled code for strings shorter
than 64 bytes.
The 64 bytes cutoff value is arbitrary from the code logic
point of view - it has been selected based on measurements,
as the largest value that still ensures a measurable gain.
Micro benchmarks of the __copy_from_user() function with
lengths in the [0-63] range show this performance gain
(shorter the string, larger the gain):
- in the [55%-4%] range on Intel Xeon(R) CPU E5-2690 v4
- in the [72%-9%] range on Intel Core i7-4810MQ
Other tested CPUs - namely Intel Atom S1260 and AMD Opteron
8216 - show no difference, because they do not expose the
ERMS feature bit.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/4533a1d101fd460f80e21329a34928fad521c1d4.1498744345.git.pabeni@redhat.com
[ Clarified the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
commit 7ebb916782 upstream.
gcc-7 warns:
In file included from arch/x86/tools/relocs_64.c:17:0:
arch/x86/tools/relocs.c: In function ‘process_64’:
arch/x86/tools/relocs.c:953:2: warning: argument 1 null where non-null expected [-Wnonnull]
qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from arch/x86/tools/relocs.h:6:0,
from arch/x86/tools/relocs_64.c:1:
/usr/include/stdlib.h:741:13: note: in a call to function ‘qsort’ declared here
extern void qsort
This happens because relocs16 is not used for ELF_BITS == 64,
so there is no point in trying to sort it.
Make the sort_relocs(&relocs16) call 32bit only.
Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Link: http://lkml.kernel.org/r/20161215124513.GA289@x4
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d4912215d1 upstream.
WARNING: CPU: 3 PID: 2840 at arch/x86/kvm/vmx.c:10966 nested_vmx_vmexit+0xdcd/0xde0 [kvm_intel]
CPU: 3 PID: 2840 Comm: qemu-system-x86 Tainted: G OE 4.12.0-rc3+ #23
RIP: 0010:nested_vmx_vmexit+0xdcd/0xde0 [kvm_intel]
Call Trace:
? kvm_check_async_pf_completion+0xef/0x120 [kvm]
? rcu_read_lock_sched_held+0x79/0x80
vmx_queue_exception+0x104/0x160 [kvm_intel]
? vmx_queue_exception+0x104/0x160 [kvm_intel]
kvm_arch_vcpu_ioctl_run+0x1171/0x1ce0 [kvm]
? kvm_arch_vcpu_load+0x47/0x240 [kvm]
? kvm_arch_vcpu_load+0x62/0x240 [kvm]
kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
? kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
? __fget+0xf3/0x210
do_vfs_ioctl+0xa4/0x700
? __fget+0x114/0x210
SyS_ioctl+0x79/0x90
do_syscall_64+0x81/0x220
entry_SYSCALL64_slow_path+0x25/0x25
This is triggered occasionally by running both win7 and win2016 in L2, in
addition, EPT is disabled on both L1 and L2. It can't be reproduced easily.
Commit 0b6ac343fc (KVM: nVMX: Correct handling of exception injection) mentioned
that "KVM wants to inject page-faults which it got to the guest. This function
assumes it is called with the exit reason in vmcs02 being a #PF exception".
Commit e011c663 (KVM: nVMX: Check all exceptions for intercept during delivery to
L2) allows to check all exceptions for intercept during delivery to L2. However,
there is no guarantee the exit reason is exception currently, when there is an
external interrupt occurred on host, maybe a time interrupt for host which should
not be injected to guest, and somewhere queues an exception, then the function
nested_vmx_check_exception() will be called and the vmexit emulation codes will
try to emulate the "Acknowledge interrupt on exit" behavior, the warning is
triggered.
Reusing the exit reason from the L2->L0 vmexit is wrong in this case,
the reason must always be EXCEPTION_NMI when injecting an exception into
L1 as a nested vmexit.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Fixes: e011c663b9 ("KVM: nVMX: Check all exceptions for intercept during delivery to L2")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f0367ee1d6 upstream.
Static checker noticed that base3 could be used uninitialized if the
segment was not present (useable). Random stack values probably would
not pass VMCS entry checks.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 1aa366163b ("KVM: x86 emulator: consolidate segment accessors")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 34b0dadbdf upstream.
Static analysis noticed that pmu->nr_arch_gp_counters can be 32
(INTEL_PMC_MAX_GENERIC) and therefore cannot be used to shift 'int'.
I didn't add BUILD_BUG_ON for it as we have a better checker.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 25462f7f52 ("KVM: x86/vPMU: Define kvm_pmu_ops to support vPMU function dispatch")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6ed071f051 upstream.
On AMD, the effect of set_nmi_mask called by emulate_iret_real and em_rsm
on hflags is reverted later on in x86_emulate_instruction where hflags are
overwritten with ctxt->emul_flags (the kvm_set_hflags call). This manifests
as a hang when rebooting Windows VMs with QEMU, OVMF, and >1 vcpu.
Instead of trying to merge ctxt->emul_flags into vcpu->arch.hflags after
an instruction is emulated, this commit deletes emul_flags altogether and
makes the emulator access vcpu->arch.hflags using two new accessors. This
way all changes, on the emulator side as well as in functions called from
the emulator and accessing vcpu state with emul_to_vcpu, are preserved.
More details on the bug and its manifestation with Windows and OVMF:
It's a KVM bug in the interaction between SMI/SMM and NMI, specific to AMD.
I believe that the SMM part explains why we started seeing this only with
OVMF.
KVM masks and unmasks NMI when entering and leaving SMM. When KVM emulates
the RSM instruction in em_rsm, the set_nmi_mask call doesn't stick because
later on in x86_emulate_instruction we overwrite arch.hflags with
ctxt->emul_flags, effectively reverting the effect of the set_nmi_mask call.
The AMD-specific hflag of interest here is HF_NMI_MASK.
When rebooting the system, Windows sends an NMI IPI to all but the current
cpu to shut them down. Only after all of them are parked in HLT will the
initiating cpu finish the restart. If NMI is masked, other cpus never get
the memo and the initiating cpu spins forever, waiting for
hal!HalpInterruptProcessorsStarted to drop. That's the symptom we observe.
Fixes: a584539b24 ("KVM: x86: pass the whole hflags field to emulator and back")
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbd68d8e84 upstream.
flush_tlb_page() passes a bogus range to flush_tlb_others() and
expects the latter to fix it up. native_flush_tlb_others() has the
fixup but Xen's version doesn't. Move the fixup to
flush_tlb_others().
AFAICS the only real effect is that, without this fix, Xen would
flush everything instead of just the one page on remote vCPUs in
when flush_tlb_page() was called.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: e7b52ffd45 ("x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range")
Link: http://lkml.kernel.org/r/10ed0e4dfea64daef10b87fb85df1746999b4dba.1492844372.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5ed386ec09 upstream.
When this function fails it just sends a SIGSEGV signal to
user-space using force_sig(). This signal is missing
essential information about the cause, e.g. the trap_nr or
an error code.
Fix this by propagating the error to the only caller of
mpx_handle_bd_fault(), do_bounds(), which sends the correct
SIGSEGV signal to the process.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: fe3d197f84 ('x86, mpx: On-demand kernel allocation of bounds tables')
Link: http://lkml.kernel.org/r/1491488362-27198-1-git-send-email-joro@8bytes.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8eabf42ae5 upstream.
Kernel text KASLR is separated into physical address and virtual
address randomization. And for virtual address randomization, we
only randomiza to get an offset between 16M and KERNEL_IMAGE_SIZE.
So the initial value of 'virt_addr' should be LOAD_PHYSICAL_ADDR,
but not the original kernel loading address 'output'.
The bug will cause kernel boot failure if kernel is loaded at a different
position than the address, 16M, which is decided at compiled time.
Kexec/kdump is such practical case.
To fix it, just assign LOAD_PHYSICAL_ADDR to virt_addr as initial
value.
Tested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 8391c73 ("x86/KASLR: Randomize virtual address separately")
Link: http://lkml.kernel.org/r/1498567146-11990-3-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 18e7a45af9 ]
As Peter suggested [1] rejecting non sampling PEBS events,
because they dont make any sense and could cause bugs
in the NMI handler [2].
[1] http://lkml.kernel.org/r/20170103094059.GC3093@worktop
[2] http://lkml.kernel.org/r/1482931866-6018-3-git-send-email-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20170103142454.GA26251@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4538286257 ]
info->si_addr is of type void __user *, so it should be compared against
something from the same address space.
This fixes the following sparse error:
arch/x86/mm/mpx.c:296:27: error: incompatible types in comparison expression (different address spaces)
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 695085b4bc ]
The Intel Denverton microserver uses a 25 MHz TSC crystal,
so we can derive its exact [*] TSC frequency
using CPUID and some arithmetic, eg.:
TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000)
[*] 'exact' is only as good as the crystal, which should be +/- 20ppm
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/306899f94804aece6d8fa8b4223ede3b48dbb59c.1484287748.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ad5013d569 ]
When x86_pmu.num_counters is 32 the shift of the integer constant 1 is
exceeding 32bit and therefor undefined behaviour.
Fix this by shifting 1ULL instead of 1.
Reported-by: CoverityScan CID#1192105 ("Bad bit shift operation")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: http://lkml.kernel.org/r/20170111114310.17928-1-colin.king@canonical.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 6d6daa2094 ]
hswep_uncore_cpu_init() uses a hardcoded physical package id 0 for the boot
cpu. This works as long as the boot CPU is actually on the physical package
0, which is normaly the case after power on / reboot.
But it fails with a NULL pointer dereference when a kdump kernel is started
on a secondary socket which has a different physical package id because the
locigal package translation for physical package 0 does not exist.
Use the logical package id of the boot cpu instead of hard coded 0.
[ tglx: Rewrote changelog once more ]
Fixes: cf6d445f68 ("perf/x86/uncore: Track packages, not per CPU data")
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Harish Chegondi <harish.chegondi@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1483628965-2890-1-git-send-email-prarit@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4e71de7986 ]
The CPU hotplug function intel_pmu_cpu_starting() sets
cpu_hw_events.excl_thread_id unconditionally to 1 when the shared exclusive
counters data structure is already availabe for the sibling thread.
This works during the boot process because the first sibling gets threadid
0 assigned and the second sibling which shares the data structure gets 1.
But when the first thread of the core is offlined and onlined again it
shares the data structure with the second thread and gets exclusive thread
id 1 assigned as well.
Prevent this by checking the threadid of the already online thread.
[ tglx: Rewrote changelog ]
Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Cc: NuoHan Qiao <qiaonuohan@huawei.com>
Cc: ak@linux.intel.com
Cc: peterz@infradead.org
Cc: kan.liang@intel.com
Cc: dave.hansen@linux.intel.com
Cc: eranian@google.com
Cc: qiaonuohan@huawei.com
Cc: davidcc@google.com
Cc: guohanjun@huawei.com
Link: http://lkml.kernel.org/r/1484536871-3131-1-git-send-email-zhouchengming1@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ce2e852ecc ]
emulator_fix_hypercall() replaces hypercall with vmcall instruction,
but it does not handle GP exception properly when writes the new instruction.
It can return X86EMUL_PROPAGATE_FAULT without setting exception information.
This leads to incorrect emulation and triggers
WARN_ON(ctxt->exception.vector > 0x1f) in x86_emulate_insn()
as discovered by syzkaller fuzzer:
WARNING: CPU: 2 PID: 18646 at arch/x86/kvm/emulate.c:5558
Call Trace:
warn_slowpath_null+0x2c/0x40 kernel/panic.c:582
x86_emulate_insn+0x16a5/0x4090 arch/x86/kvm/emulate.c:5572
x86_emulate_instruction+0x403/0x1cc0 arch/x86/kvm/x86.c:5618
emulate_instruction arch/x86/include/asm/kvm_host.h:1127 [inline]
handle_exception+0x594/0xfd0 arch/x86/kvm/vmx.c:5762
vmx_handle_exit+0x2b7/0x38b0 arch/x86/kvm/vmx.c:8625
vcpu_enter_guest arch/x86/kvm/x86.c:6888 [inline]
vcpu_run arch/x86/kvm/x86.c:6947 [inline]
Set exception information when write in emulator_fix_hypercall() fails.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: kvm@vger.kernel.org
Cc: syzkaller@googlegroups.com
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fc5f9d5f15 upstream.
Jeff Moyer reported that on his system with two memory regions 0~64G and
1T~1T+192G, and kernel option "memmap=192G!1024G" added, enabling KASLR
will make the system hang intermittently during boot. While adding 'nokaslr'
won't.
The back trace is:
Oops: 0000 [#1] SMP
RIP: memcpy_erms()
[ .... ]
Call Trace:
pmem_rw_page()
bdev_read_page()
do_mpage_readpage()
mpage_readpages()
blkdev_readpages()
__do_page_cache_readahead()
force_page_cache_readahead()
page_cache_sync_readahead()
generic_file_read_iter()
blkdev_read_iter()
__vfs_read()
vfs_read()
SyS_read()
entry_SYSCALL_64_fastpath()
This crash happens because the for loop count calculation in sync_global_pgds()
is not correct. When a mapping area crosses PGD entries, we should
calculate the starting address of region which next PGD covers and assign
it to next for loop count, but not add PGDIR_SIZE directly. The old
code works right only if the mapping area is an exact multiple of PGDIR_SIZE,
otherwize the end region could be skipped so that it can't be synchronized
to all other processes from kernel PGD init_mm.pgd.
In Jeff's system, emulated pmem area [1024G, 1216G) is smaller than
PGDIR_SIZE. While 'nokaslr' works because PAGE_OFFSET is 1T aligned, it
makes this area be mapped inside one PGD entry. With KASLR enabled,
this area could cross two PGD entries, then the next PGD entry won't
be synced to all other processes. That is why we saw empty PGD.
Fix it.
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1493864747-8506-1-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fb3a5055cd upstream.
Current DTLB load/store miss events (0x608/0x649) only counts 4K,2M and
4M page size.
Need to extend the events to support any page size (4K/2M/4M/1G).
The complete DTLB load/store miss events are:
DTLB_LOAD_MISSES.WALK_COMPLETED 0xe08
DTLB_STORE_MISSES.WALK_COMPLETED 0xe49
Signed-off-by: Kan Liang <Kan.liang@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/20170619142609.11058-1-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1be7107fbe upstream.
Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.
This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.
Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.
One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications. For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).
Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.
Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.
Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 861ce4a324 upstream.
'__vmalloc_start_set' currently only gets set in initmem_init() when
!CONFIG_NEED_MULTIPLE_NODES. This breaks detection of vmalloc address
with virt_addr_valid() with CONFIG_NEED_MULTIPLE_NODES=y, causing
a kernel crash:
[mm/usercopy] 517e1fbeb6: kernel BUG at arch/x86/mm/physaddr.c:78!
Set '__vmalloc_start_set' appropriately for that case as well.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: dc16ecf7fd ("x86-32: use specific __vmalloc_start_set flag in __virt_addr_valid")
Link: http://lkml.kernel.org/r/1494278596-30373-1-git-send-email-labbott@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9bc1f09f6f upstream.
INFO: task gnome-terminal-:1734 blocked for more than 120 seconds.
Not tainted 4.12.0-rc4+ #8
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
gnome-terminal- D 0 1734 1015 0x00000000
Call Trace:
__schedule+0x3cd/0xb30
schedule+0x40/0x90
kvm_async_pf_task_wait+0x1cc/0x270
? __vfs_read+0x37/0x150
? prepare_to_swait+0x22/0x70
do_async_page_fault+0x77/0xb0
? do_async_page_fault+0x77/0xb0
async_page_fault+0x28/0x30
This is triggered by running both win7 and win2016 on L1 KVM simultaneously,
and then gives stress to memory on L1, I can observed this hang on L1 when
at least ~70% swap area is occupied on L0.
This is due to async pf was injected to L2 which should be injected to L1,
L2 guest starts receiving pagefault w/ bogus %cr2(apf token from the host
actually), and L1 guest starts accumulating tasks stuck in D state in
kvm_async_pf_task_wait() since missing PAGE_READY async_pfs.
This patch fixes the hang by doing async pf when executing L1 guest.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a3641631d1 upstream.
If "i" is the last element in the vcpu->arch.cpuid_entries[] array, it
potentially can be exploited the vulnerability. this will out-of-bounds
read and write. Luckily, the effect is small:
/* when no next entry is found, the current entry[i] is reselected */
for (j = i + 1; ; j = (j + 1) % nent) {
struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
if (ej->function == e->function) {
It reads ej->maxphyaddr, which is user controlled. However...
ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
After cpuid_entries there is
int maxphyaddr;
struct x86_emulate_ctxt emulate_ctxt; /* 16-byte aligned */
So we have:
- cpuid_entries at offset 1B50 (6992)
- maxphyaddr at offset 27D0 (6992 + 3200 = 10192)
- padding at 27D4...27DF
- emulate_ctxt at 27E0
And it writes in the padding. Pfew, writing the ops field of emulate_ctxt
would have been much worse.
This patch fixes it by modding the index to avoid the out-of-bounds
access. Worst case, i == j and ej->function == e->function,
the loop can bail out.
Reported-by: Moguofang <moguofang@huawei.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Guofang Mo <moguofang@huawei.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bbaf0e2b1c upstream.
native_safe_halt enables interrupts, and you just shouldn't
call rcu_irq_enter() with interrupts enabled. Reorder the
call with the following local_irq_disable() to respect the
invariant.
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3780578761 upstream.
The boot code Makefile contains a straight 'readelf' invocation. This
causes build warnings in cross compile environments, when there is no
unprefixed readelf accessible via $PATH.
Add the missing $(CROSS_COMPILE) prefix.
[ tglx: Rewrote changelog ]
Fixes: 98f7852537 ("x86/boot: Refuse to build with data relocations")
Signed-off-by: Rob Landley <rob@landley.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: "H.J. Lu" <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/ced18878-693a-9576-a024-113ef39a22c0@landley.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2d1f406139 upstream.
Export the function which checks whether an MCE is a memory error to
other users so that we can reuse the logic. Drop the boot_cpu_data use,
while at it, as mce.cpuvendor already has the CPU vendor in there.
Integrate a piece from a patch from Vishal Verma
<vishal.l.verma@intel.com> to export it for modules (nfit).
The main reason we're exporting it is that the nfit handler
nfit_handle_mce() needs to detect a memory error properly before doing
its recovery actions.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Link: http://lkml.kernel.org/r/20170519093915.15413-2-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 33c9e97290 upstream.
The code to fetch a 64-bit value from user space was entirely buggered,
and has been since the code was merged in early 2016 in commit
b2f680380d ("x86/mm/32: Add support for 64-bit __get_user() on 32-bit
kernels").
Happily the buggered routine is almost certainly entirely unused, since
the normal way to access user space memory is just with the non-inlined
"get_user()", and the inlined version didn't even historically exist.
The normal "get_user()" case is handled by external hand-written asm in
arch/x86/lib/getuser.S that doesn't have either of these issues.
There were two independent bugs in __get_user_asm_u64():
- it still did the STAC/CLAC user space access marking, even though
that is now done by the wrapper macros, see commit 11f1a4b975
("x86: reorganize SMAP handling in user space accesses").
This didn't result in a semantic error, it just means that the
inlined optimized version was hugely less efficient than the
allegedly slower standard version, since the CLAC/STAC overhead is
quite high on modern Intel CPU's.
- the double register %eax/%edx was marked as an output, but the %eax
part of it was touched early in the asm, and could thus clobber other
inputs to the asm that gcc didn't expect it to touch.
In particular, that meant that the generated code could look like
this:
mov (%eax),%eax
mov 0x4(%eax),%edx
where the load of %edx obviously was _supposed_ to be from the 32-bit
word that followed the source of %eax, but because %eax was
overwritten by the first instruction, the source of %edx was
basically random garbage.
The fixes are trivial: remove the extraneous STAC/CLAC entries, and mark
the 64-bit output as early-clobber to let gcc know that no inputs should
alias with the output register.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit cbfc6c9184 upstream.
Huawei folks reported a read out-of-bounds vulnerability in kvm pio emulation.
- "inb" instruction to access PIT Mod/Command register (ioport 0x43, write only,
a read should be ignored) in guest can get a random number.
- "rep insb" instruction to access PIT register port 0x43 can control memcpy()
in emulator_pio_in_emulated() to copy max 0x400 bytes but only read 1 bytes,
which will disclose the unimportant kernel memory in host but no crash.
The similar test program below can reproduce the read out-of-bounds vulnerability:
void hexdump(void *mem, unsigned int len)
{
unsigned int i, j;
for(i = 0; i < len + ((len % HEXDUMP_COLS) ? (HEXDUMP_COLS - len % HEXDUMP_COLS) : 0); i++)
{
/* print offset */
if(i % HEXDUMP_COLS == 0)
{
printf("0x%06x: ", i);
}
/* print hex data */
if(i < len)
{
printf("%02x ", 0xFF & ((char*)mem)[i]);
}
else /* end of block, just aligning for ASCII dump */
{
printf(" ");
}
/* print ASCII dump */
if(i % HEXDUMP_COLS == (HEXDUMP_COLS - 1))
{
for(j = i - (HEXDUMP_COLS - 1); j <= i; j++)
{
if(j >= len) /* end of block, not really printing */
{
putchar(' ');
}
else if(isprint(((char*)mem)[j])) /* printable char */
{
putchar(0xFF & ((char*)mem)[j]);
}
else /* other char */
{
putchar('.');
}
}
putchar('\n');
}
}
}
int main(void)
{
int i;
if (iopl(3))
{
err(1, "set iopl unsuccessfully\n");
return -1;
}
static char buf[0x40];
/* test ioport 0x40,0x41,0x42,0x43,0x44,0x45 */
memset(buf, 0xab, sizeof(buf));
asm volatile("push %rdi;");
asm volatile("mov %0, %%rdi;"::"q"(buf));
asm volatile ("mov $0x40, %rdx;");
asm volatile ("in %dx,%al;");
asm volatile ("stosb;");
asm volatile ("mov $0x41, %rdx;");
asm volatile ("in %dx,%al;");
asm volatile ("stosb;");
asm volatile ("mov $0x42, %rdx;");
asm volatile ("in %dx,%al;");
asm volatile ("stosb;");
asm volatile ("mov $0x43, %rdx;");
asm volatile ("in %dx,%al;");
asm volatile ("stosb;");
asm volatile ("mov $0x44, %rdx;");
asm volatile ("in %dx,%al;");
asm volatile ("stosb;");
asm volatile ("mov $0x45, %rdx;");
asm volatile ("in %dx,%al;");
asm volatile ("stosb;");
asm volatile ("pop %rdi;");
hexdump(buf, 0x40);
printf("\n");
/* ins port 0x40 */
memset(buf, 0xab, sizeof(buf));
asm volatile("push %rdi;");
asm volatile("mov %0, %%rdi;"::"q"(buf));
asm volatile ("mov $0x20, %rcx;");
asm volatile ("mov $0x40, %rdx;");
asm volatile ("rep insb;");
asm volatile ("pop %rdi;");
hexdump(buf, 0x40);
printf("\n");
/* ins port 0x43 */
memset(buf, 0xab, sizeof(buf));
asm volatile("push %rdi;");
asm volatile("mov %0, %%rdi;"::"q"(buf));
asm volatile ("mov $0x20, %rcx;");
asm volatile ("mov $0x43, %rdx;");
asm volatile ("rep insb;");
asm volatile ("pop %rdi;");
hexdump(buf, 0x40);
printf("\n");
return 0;
}
The vcpu->arch.pio_data buffer is used by both in/out instrutions emulation
w/o clear after using which results in some random datas are left over in
the buffer. Guest reads port 0x43 will be ignored since it is write only,
however, the function kernel_pio() can't distigush this ignore from successfully
reads data from device's ioport. There is no new data fill the buffer from
port 0x43, however, emulator_pio_in_emulated() will copy the stale data in
the buffer to the guest unconditionally. This patch fixes it by clearing the
buffer before in instruction emulation to avoid to grant guest the stale data
in the buffer.
In addition, string I/O is not supported for in kernel device. So there is no
iteration to read ioport %RCX times for string I/O. The function kernel_pio()
just reads one round, and then copy the io size * %RCX to the guest unconditionally,
actually it copies the one round ioport data w/ other random datas which are left
over in the vcpu->arch.pio_data buffer to the guest. This patch fixes it by
introducing the string I/O support for in kernel device in order to grant the right
ioport datas to the guest.
Before the patch:
0x000000: fe 38 93 93 ff ff ab ab .8......
0x000008: ab ab ab ab ab ab ab ab ........
0x000010: ab ab ab ab ab ab ab ab ........
0x000018: ab ab ab ab ab ab ab ab ........
0x000020: ab ab ab ab ab ab ab ab ........
0x000028: ab ab ab ab ab ab ab ab ........
0x000030: ab ab ab ab ab ab ab ab ........
0x000038: ab ab ab ab ab ab ab ab ........
0x000000: f6 00 00 00 00 00 00 00 ........
0x000008: 00 00 00 00 00 00 00 00 ........
0x000010: 00 00 00 00 4d 51 30 30 ....MQ00
0x000018: 30 30 20 33 20 20 20 20 00 3
0x000020: ab ab ab ab ab ab ab ab ........
0x000028: ab ab ab ab ab ab ab ab ........
0x000030: ab ab ab ab ab ab ab ab ........
0x000038: ab ab ab ab ab ab ab ab ........
0x000000: f6 00 00 00 00 00 00 00 ........
0x000008: 00 00 00 00 00 00 00 00 ........
0x000010: 00 00 00 00 4d 51 30 30 ....MQ00
0x000018: 30 30 20 33 20 20 20 20 00 3
0x000020: ab ab ab ab ab ab ab ab ........
0x000028: ab ab ab ab ab ab ab ab ........
0x000030: ab ab ab ab ab ab ab ab ........
0x000038: ab ab ab ab ab ab ab ab ........
After the patch:
0x000000: 1e 02 f8 00 ff ff ab ab ........
0x000008: ab ab ab ab ab ab ab ab ........
0x000010: ab ab ab ab ab ab ab ab ........
0x000018: ab ab ab ab ab ab ab ab ........
0x000020: ab ab ab ab ab ab ab ab ........
0x000028: ab ab ab ab ab ab ab ab ........
0x000030: ab ab ab ab ab ab ab ab ........
0x000038: ab ab ab ab ab ab ab ab ........
0x000000: d2 e2 d2 df d2 db d2 d7 ........
0x000008: d2 d3 d2 cf d2 cb d2 c7 ........
0x000010: d2 c4 d2 c0 d2 bc d2 b8 ........
0x000018: d2 b4 d2 b0 d2 ac d2 a8 ........
0x000020: ab ab ab ab ab ab ab ab ........
0x000028: ab ab ab ab ab ab ab ab ........
0x000030: ab ab ab ab ab ab ab ab ........
0x000038: ab ab ab ab ab ab ab ab ........
0x000000: 00 00 00 00 00 00 00 00 ........
0x000008: 00 00 00 00 00 00 00 00 ........
0x000010: 00 00 00 00 00 00 00 00 ........
0x000018: 00 00 00 00 00 00 00 00 ........
0x000020: ab ab ab ab ab ab ab ab ........
0x000028: ab ab ab ab ab ab ab ab ........
0x000030: ab ab ab ab ab ab ab ab ........
0x000038: ab ab ab ab ab ab ab ab ........
Reported-by: Moguofang <moguofang@huawei.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Moguofang <moguofang@huawei.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e2c2206a18 upstream.
BUG: using __this_cpu_read() in preemptible [00000000] code: qemu-system-x86/2809
caller is __this_cpu_preempt_check+0x13/0x20
CPU: 2 PID: 2809 Comm: qemu-system-x86 Not tainted 4.11.0+ #13
Call Trace:
dump_stack+0x99/0xce
check_preemption_disabled+0xf5/0x100
__this_cpu_preempt_check+0x13/0x20
get_kvmclock_ns+0x6f/0x110 [kvm]
get_time_ref_counter+0x5d/0x80 [kvm]
kvm_hv_process_stimers+0x2a1/0x8a0 [kvm]
? kvm_hv_process_stimers+0x2a1/0x8a0 [kvm]
? kvm_arch_vcpu_ioctl_run+0xac9/0x1ce0 [kvm]
kvm_arch_vcpu_ioctl_run+0x5bf/0x1ce0 [kvm]
kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
? kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
? __fget+0xf3/0x210
do_vfs_ioctl+0xa4/0x700
? __fget+0x114/0x210
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x23/0xc2
RIP: 0033:0x7f9d164ed357
? __this_cpu_preempt_check+0x13/0x20
This can be reproduced by run kvm-unit-tests/hyperv_stimer.flat w/
CONFIG_PREEMPT and CONFIG_DEBUG_PREEMPT enabled.
Safe access to per-CPU data requires a couple of constraints, though: the
thread working with the data cannot be preempted and it cannot be migrated
while it manipulates per-CPU variables. If the thread is preempted, the
thread that replaces it could try to work with the same variables; migration
to another CPU could also cause confusion. However there is no preemption
disable when reads host per-CPU tsc rate to calculate the current kvmclock
timestamp.
This patch fixes it by utilizing get_cpu/put_cpu pair to guarantee both
__this_cpu_read() and rdtsc() are not preempted.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a575813bfe upstream.
Reported by syzkaller:
BUG: unable to handle kernel paging request at ffffffffc07f6a2e
IP: report_bug+0x94/0x120
PGD 348e12067
P4D 348e12067
PUD 348e14067
PMD 3cbd84067
PTE 80000003f7e87161
Oops: 0003 [#1] SMP
CPU: 2 PID: 7091 Comm: kvm_load_guest_ Tainted: G OE 4.11.0+ #8
task: ffff92fdfb525400 task.stack: ffffbda6c3d04000
RIP: 0010:report_bug+0x94/0x120
RSP: 0018:ffffbda6c3d07b20 EFLAGS: 00010202
do_trap+0x156/0x170
do_error_trap+0xa3/0x170
? kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
? mark_held_locks+0x79/0xa0
? retint_kernel+0x10/0x10
? trace_hardirqs_off_thunk+0x1a/0x1c
do_invalid_op+0x20/0x30
invalid_op+0x1e/0x30
RIP: 0010:kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
? kvm_load_guest_fpu.part.175+0x1c/0x170 [kvm]
kvm_arch_vcpu_ioctl_run+0xed6/0x1b70 [kvm]
kvm_vcpu_ioctl+0x384/0x780 [kvm]
? kvm_vcpu_ioctl+0x384/0x780 [kvm]
? sched_clock+0x13/0x20
? __do_page_fault+0x2a0/0x550
do_vfs_ioctl+0xa4/0x700
? up_read+0x1f/0x40
? __do_page_fault+0x2a0/0x550
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x23/0xc2
SDM mentioned that "The MXCSR has several reserved bits, and attempting to write
a 1 to any of these bits will cause a general-protection exception(#GP) to be
generated". The syzkaller forks' testcase overrides xsave area w/ random values
and steps on the reserved bits of MXCSR register. The damaged MXCSR register
values of guest will be restored to SSEx MXCSR register before vmentry. This
patch fixes it by catching userspace override MXCSR register reserved bits w/
random values and bails out immediately.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 28bf288879 upstream.
If we already entered/are about to enter SMM, don't allow switching to
INIT/SIPI_RECEIVED, otherwise the next call to kvm_apic_accept_events()
will report a warning.
Same applies if we are already in MP state INIT_RECEIVED and SMM is
requested to be turned on. Refuse to set the VCPU events in this case.
Fixes: cd7764fe9f ("KVM: x86: latch INITs while in system management mode")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 33b88e708e upstream.
It appears as though the Broadwell-EP DRAM units share the special
units quirk with Haswell-EP/KNL.
Without this patch, you get really high results (a single DRAM using 20W
of power).
The powercap driver in drivers/powercap/intel_rapl.c already has this
change.
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9abc74a22d upstream.
This is broken since ever but sadly nobody noticed.
Recent versions of GDB set DR_CONTROL unconditionally and
UML dies due to a heap corruption. It turns out that
the PTRACE_POKEUSER was copy&pasted from i386 and assumes
that addresses are 4 bytes long.
Fix that by using 8 as address size in the calculation.
Reported-by: jie cao <cj3054@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8376efd31d upstream.
Commit 11e63f6d92 added cache flushing for unaligned writes from an
iovec, covering the first and last cache line of a >= 8 byte write and
the first cache line of a < 8 byte write. But an unaligned write of
2-7 bytes can still cover two cache lines, so make sure we flush both
in that case.
Fixes: 11e63f6d92 ("x86, pmem: fix broken __copy_user_nocache ...")
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d594aa0277 upstream.
The minimum size for a new stack (512 bytes) setup for arch/x86/boot components
when the bootloader does not setup/provide a stack for the early boot components
is not "enough".
The setup code executing as part of early kernel startup code, uses the stack
beyond 512 bytes and accidentally overwrites and corrupts part of the BSS
section. This is exposed mostly in the early video setup code, where
it was corrupting BSS variables like force_x, force_y, which in-turn affected
kernel parameters such as screen_info (screen_info.orig_video_cols) and
later caused an exception/panic in console_init().
Most recent boot loaders setup the stack for early boot components, so this
stack overwriting into BSS section issue has not been exposed.
Signed-off-by: Ashish Kalra <ashish@bluestacks.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170419152015.10011-1-ashishkalra@Ashishs-MacBook-Pro.local
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 69861e0a52 upstream.
When booted as pv-guest the p2m list presented by the Xen is already
mapped to virtual addresses. In dom0 case the hypervisor might make use
of 2M- or 1G-pages for this mapping. Unfortunately while being properly
aligned in virtual and machine address space, those pages might not be
aligned properly in guest physical address space.
So when trying to obtain the guest physical address of such a page
pud_pfn() and pmd_pfn() must be avoided as those will mask away guest
physical address bits not being zero in this special case.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 84d582d236 upstream.
Recent discussion (http://marc.info/?l=xen-devel&m=149192184523741)
established that commit 72a9b18629 ("xen: Remove event channel
notification through Xen PCI platform device") (and thus commit
da72ff5bfc ("partially revert "xen: Remove event channel
notification through Xen PCI platform device"")) are unnecessary and,
in fact, prevent HVM guests from booting on Xen releases prior to 4.0
Therefore we revert both of those commits.
The summary of that discussion is below:
Here is the brief summary of the current situation:
Before the offending commit (72a9b18629):
1) INTx does not work because of the reset_watches path.
2) The reset_watches path is only taken if you have Xen > 4.0
3) The Linux Kernel by default will use vector inject if the hypervisor
support. So even INTx does not work no body running the kernel with
Xen > 4.0 would notice. Unless he explicitly disabled this feature
either in the kernel or in Xen (and this can only be disabled by
modifying the code, not user-supported way to do it).
After the offending commit (+ partial revert):
1) INTx is no longer support for HVM (only for PV guests).
2) Any HVM guest The kernel will not boot on Xen < 4.0 which does
not have vector injection support. Since the only other mode
supported is INTx which.
So based on this summary, I think before commit (72a9b18629) we were
in much better position from a user point of view.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Ross Lagerwall <ross.lagerwall@citrix.com>
Cc: xen-devel@lists.xenproject.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ab007cc94f upstream.
The PML feature is not exposed to guests so we should not be forwarding
the vmexit either.
This commit fixes BSOD 0x20001 (HYPERVISOR_ERROR) when running Hyper-V
enabled Windows Server 2016 in L1 on hardware that supports PML.
Fixes: 843e433057 ("KVM: VMX: Add PML support in VMX")
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1fb883bb82 upstream.
L2 was running with uninitialized PML fields which led to incomplete
dirty bitmap logging. This manifested as all kinds of subtle erratic
behavior of the nested guest.
Fixes: 843e433057 ("KVM: VMX: Add PML support in VMX")
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 80354c2902 upstream.
The interrupt line used for the watchdog is 12, according to the official
Intel Edison BSP code.
And indeed after fixing it we start getting an interrupt and thus the
watchdog starts working again:
[ 191.699951] Kernel panic - not syncing: Kernel Watchdog
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 78a3bb9e40 ("x86: intel-mid: add watchdog platform code for Merrifield")
Link: http://lkml.kernel.org/r/20170312150744.45493-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 75013fb16f upstream.
Fix to the exception table entry check by using probed address
instead of the address of copied instruction.
This bug may cause unexpected kernel panic if user probe an address
where an exception can happen which should be fixup by __ex_table
(e.g. copy_from_user.)
Unless user puts a kprobe on such address, this doesn't
cause any problem.
This bug has been introduced years ago, by commit:
464846888d ("x86/kprobes: Fix a bug which can modify kernel code permanently").
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 464846888d ("x86/kprobes: Fix a bug which can modify kernel code permanently")
Link: http://lkml.kernel.org/r/148829899399.28855.12581062400757221722.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 68dee8e2f2 upstream.
commit 8fd524b355 ("x86: Kill bad_dma_address variable") has killed
bad_dma_address variable and used instead of macro DMA_ERROR_CODE
which is always zero. Since dma_addr is unsigned, the statement
dma_addr >= DMA_ERROR_CODE
is always true, and not needed.
arch/x86/kernel/pci-calgary_64.c: In function ‘iommu_free’:
arch/x86/kernel/pci-calgary_64.c:299:2: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
if (unlikely((dma_addr >= DMA_ERROR_CODE) && (dma_addr < badend))) {
Fixes: 8fd524b355 ("x86: Kill bad_dma_address variable")
Signed-off-by: Nikola Pajkovsky <npajkovsky@suse.cz>
Cc: iommu@lists.linux-foundation.org
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Muli Ben-Yehuda <mulix@mulix.org>
Link: http://lkml.kernel.org/r/7612c0f9dd7c1290407dbf8e809def922006920b.1479161177.git.npajkovsky@suse.cz
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a9b4f08770 upstream.
commit d32932d02e removed the irq_retrigger callback from the IO-APIC
chip and did not add it to the new IO-APIC-IR irq chip.
There is no harm because the interrupts are resent in software when the
retrigger callback is NULL, but it's less efficient. So restore them.
[ tglx: Massaged changelog ]
Fixes: d32932d02e ("x86/irq: Convert IOAPIC to use hierarchical irqdomain interfaces")
Signed-off-by: Ruslan Ruslichenko <rruslich@cisco.com>
Cc: xe-linux-external@cisco.com
Link: http://lkml.kernel.org/r/1484662432-13580-1-git-send-email-rruslich@cisco.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5443624bed upstream.
Commit:
8ee83b2ab3 ("perf/x86/intel/pt: Add support for PTWRITE and power event tracing")
forgot to add format strings to the PT driver. So one could enable these features
by setting corresponding bits in the event config, but not by their mnemonic names.
This patch adds the format strings.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Fixes: 8ee83b2ab3 ("perf/x86/intel/pt: Add support for PTWRITE...")
Link: http://lkml.kernel.org/r/20170127151644.8585-2-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 34a477e529 upstream.
On x86-32, with CONFIG_FIRMWARE and multiple CPUs, if you enable function
graph tracing and then suspend to RAM, it will triple fault and reboot when
it resumes.
The first fault happens when booting a secondary CPU:
startup_32_smp()
load_ucode_ap()
prepare_ftrace_return()
ftrace_graph_is_dead()
(accesses 'kill_ftrace_graph')
The early head_32.S code calls into load_ucode_ap(), which has an an
ftrace hook, so it calls prepare_ftrace_return(), which calls
ftrace_graph_is_dead(), which tries to access the global
'kill_ftrace_graph' variable with a virtual address, causing a fault
because the CPU is still in real mode.
The fix is to add a check in prepare_ftrace_return() to make sure it's
running in protected mode before continuing. The check makes sure the
stack pointer is a virtual kernel address. It's a bit of a hack, but
it's not very intrusive and it works well enough.
For reference, here are a few other (more difficult) ways this could
have potentially been fixed:
- Move startup_32_smp()'s call to load_ucode_ap() down to *after* paging
is enabled. (No idea what that would break.)
- Track down load_ucode_ap()'s entire callee tree and mark all the
functions 'notrace'. (Probably not realistic.)
- Pause graph tracing in ftrace_suspend_notifier_call() or bringup_cpu()
or __cpu_up(), and ensure that the pause facility can be queried from
real mode.
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>
Cc: linux-acpi@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/5c1272269a580660703ed2eccf44308e790c7a98.1492123841.git.jpoimboe@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0dc9c639e6 upstream.
The NFIT MCE handler callback (for handling media errors on NVDIMMs)
takes a mutex to add the location of a memory error to a list. But since
the notifier call chain for machine checks (x86_mce_decoder_chain) is
atomic, we get a lockdep splat like:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
in_atomic(): 1, irqs_disabled(): 0, pid: 4, name: kworker/0:0
[..]
Call Trace:
dump_stack
___might_sleep
__might_sleep
mutex_lock_nested
? __lock_acquire
nfit_handle_mce
notifier_call_chain
atomic_notifier_call_chain
? atomic_notifier_call_chain
mce_gen_pool_process
Convert the notifier to a blocking one which gets to run only in process
context.
Boris: remove the notifier call in atomic context in print_mce(). For
now, let's print the MCE on the atomic path so that we can make sure
they go out and get logged at least.
Fixes: 6839a6d96f ("nfit: do an ARS scrub on hitting a latent media error")
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20170411224457.24777-1-vishal.l.verma@intel.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 29f72ce3e4 upstream.
MCA bank 3 is reserved on systems pre-Fam17h, so it didn't have a name.
However, MCA bank 3 is defined on Fam17h systems and can be accessed
using legacy MSRs. Without a name we get a stack trace on Fam17h systems
when trying to register sysfs files for bank 3 on kernels that don't
recognize Scalable MCA.
Call MCA bank 3 "decode_unit" since this is what it represents on
Fam17h. This will allow kernels without SMCA support to see this bank on
Fam17h+ and prevent the stack trace. This will not affect older systems
since this bank is reserved on them, i.e. it'll be ignored.
Tested on AMD Fam15h and Fam17h systems.
WARNING: CPU: 26 PID: 1 at lib/kobject.c:210 kobject_add_internal
kobject: (ffff88085bb256c0): attempted to be registered with empty name!
...
Call Trace:
kobject_add_internal
kobject_add
kobject_create_and_add
threshold_create_device
threshold_init_device
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1490102285-3659-1-git-send-email-Yazen.Ghannam@amd.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a4866aa812 upstream.
Under CONFIG_STRICT_DEVMEM, reading System RAM through /dev/mem is
disallowed. However, on x86, the first 1MB was always allowed for BIOS
and similar things, regardless of it actually being System RAM. It was
possible for heap to end up getting allocated in low 1MB RAM, and then
read by things like x86info or dd, which would trip hardened usercopy:
usercopy: kernel memory exposure attempt detected from ffff880000090000 (dma-kmalloc-256) (4096 bytes)
This changes the x86 exception for the low 1MB by reading back zeros for
System RAM areas instead of blindly allowing them. More work is needed to
extend this to mmap, but currently mmap doesn't go through usercopy, so
hardened usercopy won't Oops the kernel.
Reported-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Tested-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
