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commit f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 upstream.
mc_saved_tmp is a static array allocated on the stack, we need to make
sure mc_saved_count stays within its bounds, otherwise we're overflowing
the stack in _save_mc(). A specially crafted microcode header could lead
to a kernel crash or potentially kernel execution.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd upstream.
On x86-64, __copy_instruction() always returns 0 (error) if the
instruction uses %rip-relative addressing. This is because
kernel_insn_init() is called the second time for 'insn' instance
in such cases and sets all its fields to 0.
Because of this, trying to place a kprobe on such instruction
will fail, register_kprobe() will return -EINVAL.
This patch fixes the problem.
Signed-off-by: Eugene Shatokhin <eugene.shatokhin@rosalab.ru>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20150317100918.28349.94654.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 425be5679fd292a3c36cb1fe423086708a99f11a upstream.
The early_idt_handlers asm code generates an array of entry
points spaced nine bytes apart. It's not really clear from that
code or from the places that reference it what's going on, and
the code only works in the first place because GAS never
generates two-byte JMP instructions when jumping to global
labels.
Clean up the code to generate the correct array stride (member size)
explicitly. This should be considerably more robust against
screw-ups, as GAS will warn if a .fill directive has a negative
count. Using '. =' to advance would have been even more robust
(it would generate an actual error if it tried to move
backwards), but it would pad with nulls, confusing anyone who
tries to disassemble the code. The new scheme should be much
clearer to future readers.
While we're at it, improve the comments and rename the array and
common code.
Binutils may start relaxing jumps to non-weak labels. If so,
this change will fix our build, and we may need to backport this
change.
Before, on x86_64:
0000000000000000 <early_idt_handlers>:
0: 6a 00 pushq $0x0
2: 6a 00 pushq $0x0
4: e9 00 00 00 00 jmpq 9 <early_idt_handlers+0x9>
5: R_X86_64_PC32 early_idt_handler-0x4
...
48: 66 90 xchg %ax,%ax
4a: 6a 08 pushq $0x8
4c: e9 00 00 00 00 jmpq 51 <early_idt_handlers+0x51>
4d: R_X86_64_PC32 early_idt_handler-0x4
...
117: 6a 00 pushq $0x0
119: 6a 1f pushq $0x1f
11b: e9 00 00 00 00 jmpq 120 <early_idt_handler>
11c: R_X86_64_PC32 early_idt_handler-0x4
After:
0000000000000000 <early_idt_handler_array>:
0: 6a 00 pushq $0x0
2: 6a 00 pushq $0x0
4: e9 14 01 00 00 jmpq 11d <early_idt_handler_common>
...
48: 6a 08 pushq $0x8
4a: e9 d1 00 00 00 jmpq 120 <early_idt_handler_common>
4f: cc int3
50: cc int3
...
117: 6a 00 pushq $0x0
119: 6a 1f pushq $0x1f
11b: eb 03 jmp 120 <early_idt_handler_common>
11d: cc int3
11e: cc int3
11f: cc int3
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Binutils <binutils@sourceware.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Jan Beulich <JBeulich@suse.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/ac027962af343b0c599cbfcf50b945ad2ef3d7a8.1432336324.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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savings and to improve performance
commit b253149b843f89cd300cbdbea27ce1f847506f99 upstream.
In Linux-3.9 we removed the mwait_idle() loop:
69fb3676df33 ("x86 idle: remove mwait_idle() and "idle=mwait" cmdline param")
The reasoning was that modern machines should be sufficiently
happy during the boot process using the default_idle() HALT
loop, until cpuidle loads and either acpi_idle or intel_idle
invoke the newer MWAIT-with-hints idle loop.
But two machines reported problems:
1. Certain Core2-era machines support MWAIT-C1 and HALT only.
MWAIT-C1 is preferred for optimal power and performance.
But if they support just C1, cpuidle never loads and
so they use the boot-time default idle loop forever.
2. Some laptops will boot-hang if HALT is used,
but will boot successfully if MWAIT is used.
This appears to be a hidden assumption in BIOS SMI,
that is presumably valid on the proprietary OS
where the BIOS was validated.
https://bugzilla.kernel.org/show_bug.cgi?id=60770
So here we effectively revert the patch above, restoring
the mwait_idle() loop. However, we don't bother restoring
the idle=mwait cmdline parameter, since it appears to add
no value.
Maintainer notes:
For 3.9, simply revert 69fb3676df
for 3.10, patch -F3 applies, fuzz needed due to __cpuinit use in
context For 3.11, 3.12, 3.13, this patch applies cleanly
Tested-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Mike Galbraith <bitbucket@online.de>
Cc: <stable@vger.kernel.org> # 3.9+
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ian Malone <ibmalone@gmail.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/345254a551eb5a6a866e048d7ab570fd2193aca4.1389763084.git.len.brown@intel.com
[ Ported to recent kernels. ]
[ Mike: 3.10 backport ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 80313b3078fcd2ca51970880d90757f05879a193 upstream.
The ASRock Q1900DC-ITX mainboard (Baytrail-D) hangs randomly in
both BIOS and UEFI mode while rebooting unless reboot=pci is
used. Add a quirk to reboot via the pci method.
The problem is very intermittent and hard to debug, it might succeed
rebooting just fine 40 times in a row - but fails half a dozen times
the next day. It seems to be slightly less common in BIOS CSM mode
than native UEFI (with the CSM disabled), but it does happen in either
mode. Since I've started testing this patch in late january, rebooting
has been 100% reliable.
Most of the time it already hangs during POST, but occasionally it
might even make it through the bootloader and the kernel might even
start booting, but then hangs before the mode switch. The same symptoms
occur with grub-efi, gummiboot and grub-pc, just as well as (at least)
kernel 3.16-3.19 and 4.0-rc6 (I haven't tried older kernels than 3.16).
Upgrading to the most current mainboard firmware of the ASRock
Q1900DC-ITX, version 1.20, does not improve the situation.
( Searching the web seems to suggest that other Bay Trail-D mainboards
might be affected as well. )
--
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150330224427.0fb58e42@mir
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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__restore_xstate_sig()
commit a7c80ebcac3068b1c3cb27d538d29558c30010c8 upstream.
math_state_restore() assumes it is called with irqs disabled,
but this is not true if the caller is __restore_xstate_sig().
This means that if ia32_fxstate == T and __copy_from_user()
fails, __restore_xstate_sig() returns with irqs disabled too.
This triggers:
BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:41
dump_stack
___might_sleep
? _raw_spin_unlock_irqrestore
__might_sleep
down_read
? _raw_spin_unlock_irqrestore
print_vma_addr
signal_fault
sys32_rt_sigreturn
Change __restore_xstate_sig() to call set_used_math()
unconditionally. This avoids enabling and disabling interrupts
in math_state_restore(). If copy_from_user() fails, we can
simply do fpu_finit() by hand.
[ Note: this is only the first step. math_state_restore() should
not check used_math(), it should set this flag. While
init_fpu() should simply die. ]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150307153844.GB25954@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 956421fbb74c3a6261903f3836c0740187cf038b upstream.
'ret_from_fork' checks TIF_IA32 to determine whether 'pt_regs' and
the related state make sense for 'ret_from_sys_call'. This is
entirely the wrong check. TS_COMPAT would make a little more
sense, but there's really no point in keeping this optimization
at all.
This fixes a return to the wrong user CS if we came from int
0x80 in a 64-bit task.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/4710be56d76ef994ddf59087aad98c000fbab9a4.1424989793.git.luto@amacapital.net
[ Backported from tip:x86/asm. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7ddc6a2199f1da405a2fb68c40db8899b1a8cd87 upstream.
These functions can be executed on the int3 stack, so kprobes
are dangerous. Tracing is probably a bad idea, too.
Fixes: b645af2d5905 ("x86_64, traps: Rework bad_iret")
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/50e33d26adca60816f3ba968875801652507d0c4.1416870125.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.10:
- Use __kprobes instead of NOKPROBE_SYMBOL()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3669ef9fa7d35f573ec9c0e0341b29251c2734a7 upstream.
The Witcher 2 did something like this to allocate a TLS segment index:
struct user_desc u_info;
bzero(&u_info, sizeof(u_info));
u_info.entry_number = (uint32_t)-1;
syscall(SYS_set_thread_area, &u_info);
Strictly speaking, this code was never correct. It should have set
read_exec_only and seg_not_present to 1 to indicate that it wanted
to find a free slot without putting anything there, or it should
have put something sensible in the TLS slot if it wanted to allocate
a TLS entry for real. The actual effect of this code was to
allocate a bogus segment that could be used to exploit espfix.
The set_thread_area hardening patches changed the behavior, causing
set_thread_area to return -EINVAL and crashing the game.
This changes set_thread_area to interpret this as a request to find
a free slot and to leave it empty, which isn't *quite* what the game
expects but should be close enough to keep it working. In
particular, using the code above to allocate two segments will
allocate the same segment both times.
According to FrostbittenKing on Github, this fixes The Witcher 2.
If this somehow still causes problems, we could instead allocate
a limit==0 32-bit data segment, but that seems rather ugly to me.
Fixes: 41bdc78544b8 x86/tls: Validate TLS entries to protect espfix
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/0cb251abe1ff0958b8e468a9a9a905b80ae3a746.1421954363.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 520452172e6b318f3a8bd9d4fe1e25066393de25 upstream.
Many users see this message when booting without knowning that it is
of no importance and that TSC calibration may have succeeded by
another way.
As explained by Paul Bolle in
http://lkml.kernel.org/r/1348488259.1436.22.camel@x61.thuisdomein
"Fast TSC calibration failed" should not be considered as an error
since other calibration methods are being tried afterward. At most,
those send a warning if they fail (not an error). So let's change
the message from error to warning.
[ tglx: Make if pr_info. It's really not important at all ]
Fixes: c767a54ba065 x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
Signed-off-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Link: http://lkml.kernel.org/r/1418106470-6906-1-git-send-email-alexandre.f.demers@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 32c6590d126836a062b3140ed52d898507987017 upstream.
The Hyper-V clocksource is continuous; mark it accordingly.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: jasowang@redhat.com
Cc: gregkh@linuxfoundation.org
Cc: devel@linuxdriverproject.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Link: http://lkml.kernel.org/r/1421108762-3331-1-git-send-email-kys@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 237d28db036e411f22c03cfd5b0f6dc2aa9bf3bc upstream.
If the function graph tracer traces a jprobe callback, the system will
crash. This can easily be demonstrated by compiling the jprobe
sample module that is in the kernel tree, loading it and running the
function graph tracer.
# modprobe jprobe_example.ko
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
# ls
The first two commands end up in a nice crash after the first fork.
(do_fork has a jprobe attached to it, so "ls" just triggers that fork)
The problem is caused by the jprobe_return() that all jprobe callbacks
must end with. The way jprobes works is that the function a jprobe
is attached to has a breakpoint placed at the start of it (or it uses
ftrace if fentry is supported). The breakpoint handler (or ftrace callback)
will copy the stack frame and change the ip address to return to the
jprobe handler instead of the function. The jprobe handler must end
with jprobe_return() which swaps the stack and does an int3 (breakpoint).
This breakpoint handler will then put back the saved stack frame,
simulate the instruction at the beginning of the function it added
a breakpoint to, and then continue on.
For function tracing to work, it hijakes the return address from the
stack frame, and replaces it with a hook function that will trace
the end of the call. This hook function will restore the return
address of the function call.
If the function tracer traces the jprobe handler, the hook function
for that handler will not be called, and its saved return address
will be used for the next function. This will result in a kernel crash.
To solve this, pause function tracing before the jprobe handler is called
and unpause it before it returns back to the function it probed.
Some other updates:
Used a variable "saved_sp" to hold kcb->jprobe_saved_sp. This makes the
code look a bit cleaner and easier to understand (various tries to fix
this bug required this change).
Note, if fentry is being used, jprobes will change the ip address before
the function graph tracer runs and it will not be able to trace the
function that the jprobe is probing.
Link: http://lkml.kernel.org/r/20150114154329.552437962@goodmis.org
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit af91568e762d04931dcbdd6bef4655433d8b9418 upstream.
The uncore_collect_events functions assumes that event group
might contain only uncore events which is wrong, because it
might contain any type of events.
This bug leads to uncore framework touching 'not' uncore events,
which could end up all sorts of bugs.
One was triggered by Vince's perf fuzzer, when the uncore code
touched breakpoint event private event space as if it was uncore
event and caused BUG:
BUG: unable to handle kernel paging request at ffffffff82822068
IP: [<ffffffff81020338>] uncore_assign_events+0x188/0x250
...
The code in uncore_assign_events() function was looking for
event->hw.idx data while the event was initialized as a
breakpoint with different members in event->hw union.
This patch forces uncore_collect_events() to collect only uncore
events.
Reported-by: Vince Weaver <vince@deater.net>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/1418243031-20367-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3fb2f4237bb452eb4e98f6a5dbd5a445b4fed9d0 upstream.
It turns out that there's a lurking ABI issue. GCC, when
compiling this in a 32-bit program:
struct user_desc desc = {
.entry_number = idx,
.base_addr = base,
.limit = 0xfffff,
.seg_32bit = 1,
.contents = 0, /* Data, grow-up */
.read_exec_only = 0,
.limit_in_pages = 1,
.seg_not_present = 0,
.useable = 0,
};
will leave .lm uninitialized. This means that anything in the
kernel that reads user_desc.lm for 32-bit tasks is unreliable.
Revert the .lm check in set_thread_area(). The value never did
anything in the first place.
Fixes: 0e58af4e1d21 ("x86/tls: Disallow unusual TLS segments")
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/d7875b60e28c512f6a6fc0baf5714d58e7eaadbb.1418856405.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 29fa6825463c97e5157284db80107d1bfac5d77b upstream.
paravirt_enabled has the following effects:
- Disables the F00F bug workaround warning. There is no F00F bug
workaround any more because Linux's standard IDT handling already
works around the F00F bug, but the warning still exists. This
is only cosmetic, and, in any event, there is no such thing as
KVM on a CPU with the F00F bug.
- Disables 32-bit APM BIOS detection. On a KVM paravirt system,
there should be no APM BIOS anyway.
- Disables tboot. I think that the tboot code should check the
CPUID hypervisor bit directly if it matters.
- paravirt_enabled disables espfix32. espfix32 should *not* be
disabled under KVM paravirt.
The last point is the purpose of this patch. It fixes a leak of the
high 16 bits of the kernel stack address on 32-bit KVM paravirt
guests. Fixes CVE-2014-8134.
Suggested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f647d7c155f069c1a068030255c300663516420e upstream.
Otherwise, if buggy user code points DS or ES into the TLS
array, they would be corrupted after a context switch.
This also significantly improves the comments and documents some
gotchas in the code.
Before this patch, the both tests below failed. With this
patch, the es test passes, although the gsbase test still fails.
----- begin es test -----
/*
* Copyright (c) 2014 Andy Lutomirski
* GPL v2
*/
static unsigned short GDT3(int idx)
{
return (idx << 3) | 3;
}
static int create_tls(int idx, unsigned int base)
{
struct user_desc desc = {
.entry_number = idx,
.base_addr = base,
.limit = 0xfffff,
.seg_32bit = 1,
.contents = 0, /* Data, grow-up */
.read_exec_only = 0,
.limit_in_pages = 1,
.seg_not_present = 0,
.useable = 0,
};
if (syscall(SYS_set_thread_area, &desc) != 0)
err(1, "set_thread_area");
return desc.entry_number;
}
int main()
{
int idx = create_tls(-1, 0);
printf("Allocated GDT index %d\n", idx);
unsigned short orig_es;
asm volatile ("mov %%es,%0" : "=rm" (orig_es));
int errors = 0;
int total = 1000;
for (int i = 0; i < total; i++) {
asm volatile ("mov %0,%%es" : : "rm" (GDT3(idx)));
usleep(100);
unsigned short es;
asm volatile ("mov %%es,%0" : "=rm" (es));
asm volatile ("mov %0,%%es" : : "rm" (orig_es));
if (es != GDT3(idx)) {
if (errors == 0)
printf("[FAIL]\tES changed from 0x%hx to 0x%hx\n",
GDT3(idx), es);
errors++;
}
}
if (errors) {
printf("[FAIL]\tES was corrupted %d/%d times\n", errors, total);
return 1;
} else {
printf("[OK]\tES was preserved\n");
return 0;
}
}
----- end es test -----
----- begin gsbase test -----
/*
* gsbase.c, a gsbase test
* Copyright (c) 2014 Andy Lutomirski
* GPL v2
*/
static unsigned char *testptr, *testptr2;
static unsigned char read_gs_testvals(void)
{
unsigned char ret;
asm volatile ("movb %%gs:%1, %0" : "=r" (ret) : "m" (*testptr));
return ret;
}
int main()
{
int errors = 0;
testptr = mmap((void *)0x200000000UL, 1, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
if (testptr == MAP_FAILED)
err(1, "mmap");
testptr2 = mmap((void *)0x300000000UL, 1, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
if (testptr2 == MAP_FAILED)
err(1, "mmap");
*testptr = 0;
*testptr2 = 1;
if (syscall(SYS_arch_prctl, ARCH_SET_GS,
(unsigned long)testptr2 - (unsigned long)testptr) != 0)
err(1, "ARCH_SET_GS");
usleep(100);
if (read_gs_testvals() == 1) {
printf("[OK]\tARCH_SET_GS worked\n");
} else {
printf("[FAIL]\tARCH_SET_GS failed\n");
errors++;
}
asm volatile ("mov %0,%%gs" : : "r" (0));
if (read_gs_testvals() == 0) {
printf("[OK]\tWriting 0 to gs worked\n");
} else {
printf("[FAIL]\tWriting 0 to gs failed\n");
errors++;
}
usleep(100);
if (read_gs_testvals() == 0) {
printf("[OK]\tgsbase is still zero\n");
} else {
printf("[FAIL]\tgsbase was corrupted\n");
errors++;
}
return errors == 0 ? 0 : 1;
}
----- end gsbase test -----
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/509d27c9fec78217691c3dad91cec87e1006b34a.1418075657.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 0e58af4e1d2166e9e33375a0f121e4867010d4f8 upstream.
Users have no business installing custom code segments into the
GDT, and segments that are not present but are otherwise valid
are a historical source of interesting attacks.
For completeness, block attempts to set the L bit. (Prior to
this patch, the L bit would have been silently dropped.)
This is an ABI break. I've checked glibc, musl, and Wine, and
none of them look like they'll have any trouble.
Note to stable maintainers: this is a hardening patch that fixes
no known bugs. Given the possibility of ABI issues, this
probably shouldn't be backported quickly.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 41bdc78544b8a93a9c6814b8bbbfef966272abbe upstream.
Installing a 16-bit RW data segment into the GDT defeats espfix.
AFAICT this will not affect glibc, Wine, or dosemu at all.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 338b522ca43cfd32d11a370f4203bcd089c6c877 upstream.
With -cpu host, KVM reports LBR and extra_regs support, if the host has
support.
When the guest perf driver tries to access LBR or extra_regs MSR,
it #GPs all MSR accesses,since KVM doesn't handle LBR and extra_regs support.
So check the related MSRs access right once at initialization time to avoid
the error access at runtime.
For reproducing the issue, please build the kernel with CONFIG_KVM_INTEL = y
(for host kernel).
And CONFIG_PARAVIRT = n and CONFIG_KVM_GUEST = n (for guest kernel).
Start the guest with -cpu host.
Run perf record with --branch-any or --branch-filter in guest to trigger LBR
Run perf stat offcore events (E.g. LLC-loads/LLC-load-misses ...) in guest to
trigger offcore_rsp #GP
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/1405365957-20202-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dongsu Park <dongsu.park@profitbricks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit c1118b3602c2329671ad5ec8bdf8e374323d6343 upstream.
On x86_64, kernel text mappings are mapped read-only with CONFIG_DEBUG_RODATA.
In that case, KVM will fail to patch VMCALL instructions to VMMCALL
as required on AMD processors.
The failure mode is currently a divide-by-zero exception, which obviously
is a KVM bug that has to be fixed. However, picking the right instruction
between VMCALL and VMMCALL will be faster and will help if you cannot upgrade
the hypervisor.
Reported-by: Chris Webb <chris@arachsys.com>
Tested-by: Chris Webb <chris@arachsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 2cd3949f702692cf4c5d05b463f19cd706a92dd3 upstream.
We have some very similarly named command-line options:
arch/x86/kernel/cpu/common.c:__setup("noxsave", x86_xsave_setup);
arch/x86/kernel/cpu/common.c:__setup("noxsaveopt", x86_xsaveopt_setup);
arch/x86/kernel/cpu/common.c:__setup("noxsaves", x86_xsaves_setup);
__setup() is designed to match options that take arguments, like
"foo=bar" where you would have:
__setup("foo", x86_foo_func...);
The problem is that "noxsave" actually _matches_ "noxsaves" in
the same way that "foo" matches "foo=bar". If you boot an old
kernel that does not know about "noxsaves" with "noxsaves" on the
command line, it will interpret the argument as "noxsave", which
is not what you want at all.
This makes the "noxsave" handler only return success when it finds
an *exact* match.
[ tglx: We really need to make __setup() more robust. ]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141111220133.FE053984@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit b645af2d5905c4e32399005b867987919cbfc3ae upstream.
It's possible for iretq to userspace to fail. This can happen because
of a bad CS, SS, or RIP.
Historically, we've handled it by fixing up an exception from iretq to
land at bad_iret, which pretends that the failed iret frame was really
the hardware part of #GP(0) from userspace. To make this work, there's
an extra fixup to fudge the gs base into a usable state.
This is suboptimal because it loses the original exception. It's also
buggy because there's no guarantee that we were on the kernel stack to
begin with. For example, if the failing iret happened on return from an
NMI, then we'll end up executing general_protection on the NMI stack.
This is bad for several reasons, the most immediate of which is that
general_protection, as a non-paranoid idtentry, will try to deliver
signals and/or schedule from the wrong stack.
This patch throws out bad_iret entirely. As a replacement, it augments
the existing swapgs fudge into a full-blown iret fixup, mostly written
in C. It's should be clearer and more correct.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 6f442be2fb22be02cafa606f1769fa1e6f894441 upstream.
On a 32-bit kernel, this has no effect, since there are no IST stacks.
On a 64-bit kernel, #SS can only happen in user code, on a failed iret
to user space, a canonical violation on access via RSP or RBP, or a
genuine stack segment violation in 32-bit kernel code. The first two
cases don't need IST, and the latter two cases are unlikely fatal bugs,
and promoting them to double faults would be fine.
This fixes a bug in which the espfix64 code mishandles a stack segment
violation.
This saves 4k of memory per CPU and a tiny bit of code.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit af726f21ed8af2cdaa4e93098dc211521218ae65 upstream.
There's nothing special enough about the espfix64 double fault fixup to
justify writing it in assembly. Move it to C.
This also fixes a bug: if the double fault came from an IST stack, the
old asm code would return to a partially uninitialized stack frame.
Fixes: 3891a04aafd668686239349ea58f3314ea2af86b
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 1996388e9f4e3444db8273bc08d25164d2967c21 upstream.
This was discussed back in February:
https://lkml.org/lkml/2014/2/18/956
But I never saw a patch come out of it.
On IvyBridge we share the SandyBridge cache event tables, but the
dTLB-load-miss event is not compatible. Patch it up after
the fact to the proper DTLB_LOAD_MISSES.DEMAND_LD_MISS_CAUSES_A_WALK
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1407141528200.17214@vincent-weaver-1.umelst.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Hou Pengyang <houpengyang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit c0a717f23dccdb6e3b03471bc846fdc636f2b353 upstream.
Save the patch while we're running on the BSP instead of later, before
the initrd has been jettisoned. More importantly, on 32-bit we need to
access the physical address instead of the virtual.
This way we actually do find it on the APs instead of having to go
through the initrd each time.
Tested-by: Richard Hendershot <rshendershot@mchsi.com>
Fixes: 5335ba5cf475 ("x86, microcode, AMD: Fix early ucode loading")
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 4750a0d112cbfcc744929f1530ffe3193436766c upstream.
Konrad triggered the following splat below in a 32-bit guest on an AMD
box. As it turns out, in save_microcode_in_initrd_amd() we're using the
*physical* address of the container *after* we have enabled paging and
thus we #PF in load_microcode_amd() when trying to access the microcode
container in the ramdisk range.
Because the ramdisk is exactly there:
[ 0.000000] RAMDISK: [mem 0x35e04000-0x36ef9fff]
and we fault at 0x35e04304.
And since this guest doesn't relocate the ramdisk, we don't do the
computation which will give us the correct virtual address and we end up
with the PA.
So, we should actually be using virtual addresses on 32-bit too by the
time we're freeing the initrd. Do that then!
Unpacking initramfs...
BUG: unable to handle kernel paging request at 35d4e304
IP: [<c042e905>] load_microcode_amd+0x25/0x4a0
*pde = 00000000
Oops: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.1-302.fc21.i686 #1
Hardware name: Xen HVM domU, BIOS 4.4.1 10/01/2014
task: f5098000 ti: f50d0000 task.ti: f50d0000
EIP: 0060:[<c042e905>] EFLAGS: 00010246 CPU: 0
EIP is at load_microcode_amd+0x25/0x4a0
EAX: 00000000 EBX: f6e9ec4c ECX: 00001ec4 EDX: 00000000
ESI: f5d4e000 EDI: 35d4e2fc EBP: f50d1ed0 ESP: f50d1e94
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 35d4e304 CR3: 00e33000 CR4: 000406d0
Stack:
00000000 00000000 f50d1ebc f50d1ec4 f5d4e000 c0d7735a f50d1ed0 15a3d17f
f50d1ec4 00600f20 00001ec4 bfb83203 f6e9ec4c f5d4e000 c0d7735a f50d1ed8
c0d80861 f50d1ee0 c0d80429 f50d1ef0 c0d889a9 f5d4e000 c0000000 f50d1f04
Call Trace:
? unpack_to_rootfs
? unpack_to_rootfs
save_microcode_in_initrd_amd
save_microcode_in_initrd
free_initrd_mem
populate_rootfs
? unpack_to_rootfs
do_one_initcall
? unpack_to_rootfs
? repair_env_string
? proc_mkdir
kernel_init_freeable
kernel_init
ret_from_kernel_thread
? rest_init
Reported-and-tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
References: https://bugzilla.redhat.com/show_bug.cgi?id=1158204
Fixes: 75a1ba5b2c52 ("x86, microcode, AMD: Unify valid container checks")
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20141101100100.GA4462@pd.tnic
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 81f49a8fd7088cfcb588d182eeede862c0e3303e upstream.
is_compat_task() is the wrong check for audit arch; the check should
be is_ia32_task(): x32 syscalls should be AUDIT_ARCH_X86_64, not
AUDIT_ARCH_I386.
CONFIG_AUDITSYSCALL is currently incompatible with x32, so this has
no visible effect.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/a0138ed8c709882aec06e4acc30bfa9b623b8717.1409954077.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit b47dcbdc5161d3d5756f430191e2840d9b855492 upstream.
If the TSC is unusable or disabled, then this patch fixes:
- Confusion while trying to clear old APIC interrupts.
- Division by zero and incorrect programming of the TSC deadline
timer.
This fixes boot if the CPU has a TSC deadline timer but a missing or
broken TSC. The failure to boot can be observed with qemu using
-cpu qemu64,-tsc,+tsc-deadline
This also happens to me in nested KVM for unknown reasons.
With this patch, I can boot cleanly (although without a TSC).
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Bandan Das <bsd@redhat.com>
Link: http://lkml.kernel.org/r/e2fa274e498c33988efac0ba8b7e3120f7f92d78.1413393027.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 849f5d894383d25c49132437aa289c9a9c98d5df upstream.
Add Braswell PCI ID to list of supported ID's for the IOSF driver.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: http://lkml.kernel.org/r/1411017231-20807-2-git-send-email-david.e.box@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit aece118e487a744eafcdd0c77fe32b55ee2092a1 upstream.
Intel processors which don't report cache information via cpuid(2)
or cpuid(4) need quirk code in the legacy_cache_size callback to
report this data. For Intel that callback is is intel_size_cache().
This patch enables calling of cpu_detect_cache_sizes() inside of
init_intel() and hence the calling of the legacy_cache callback in
intel_size_cache(). Adding this call will ensure that PIII Tualatin
currently in intel_size_cache() and Quark SoC X1000 being added to
intel_size_cache() in this patch will report their respective cache
sizes.
This model of calling cpu_detect_cache_sizes() is consistent with
AMD/Via/Cirix/Transmeta and Centaur.
Also added is a string to idenitfy the Quark as Quark SoC X1000
giving better and more descriptive output via /proc/cpuinfo
Adding cpu_detect_cache_sizes to init_intel() will enable calling
of intel_size_cache() on Intel processors which currently no code
can reach. Therefore this patch will also re-enable reporting
of PIII Tualatin cache size information as well as add
Quark SoC X1000 support.
Comment text and cache flow logic suggested by Thomas Gleixner
Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: davej@redhat.com
Cc: hmh@hmh.eng.br
Link: http://lkml.kernel.org/r/1412641189-12415-3-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 04725ad59474d24553d526fa774179ecd2922342 upstream.
Introduce PCI IDs macro for the list of supported product:
BayTrail & Quark X1000.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Link: http://lkml.kernel.org/r/1399668248-24199-5-git-send-email-david.e.box@linux.intel.com
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 90916e048c1e0c1d379577e43ab9b8e331490cfb upstream.
Add PCI device ID, i.e. that of the Host Bridge,
for IOSF MBI driver.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Link: http://lkml.kernel.org/r/1399668248-24199-4-git-send-email-david.e.box@linux.intel.com
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6b8f0c8780c71d78624f736d7849645b64cc88b7 upstream.
Currently drivers that run on non-IOSF systems (Core/Xeon) can't use the IOSF
driver on SOC's without selecting it which forces an unnecessary and limiting
dependency. Provides dummy functions to allow these modules to conditionally
use the driver on IOSF equipped platforms without impacting their ability to
compile and load on non-IOSF platforms. Build default m to ensure availability
on x86 SOC's.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: http://lkml.kernel.org/r/1399668248-24199-2-git-send-email-david.e.box@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 8c7aa698baca5e8f1ba9edb68081f1e7a1abf455 upstream.
The NT flag doesn't do anything in long mode other than causing IRET
to #GP. Oddly, CPL3 code can still set NT using popf.
Entry via hardware or software interrupt clears NT automatically, so
the only relevant entries are fast syscalls.
If user code causes kernel code to run with NT set, then there's at
least some (small) chance that it could cause trouble. For example,
user code could cause a call to EFI code with NT set, and who knows
what would happen? Apparently some games on Wine sometimes do
this (!), and, if an IRET return happens, they will segfault. That
segfault cannot be handled, because signal delivery fails, too.
This patch programs the CPU to clear NT on entry via SYSCALL (both
32-bit and 64-bit, by my reading of the AMD APM), and it clears NT
in software on entry via SYSENTER.
To save a few cycles, this borrows a trick from Jan Beulich in Xen:
it checks whether NT is set before trying to clear it. As a result,
it seems to have very little effect on SYSENTER performance on my
machine.
There's another minor bug fix in here: it looks like the CFI
annotations were wrong if CONFIG_AUDITSYSCALL=n.
Testers beware: on Xen, SYSENTER with NT set turns into a GPF.
I haven't touched anything on 32-bit kernels.
The syscall mask change comes from a variant of this patch by Anish
Bhatt.
Note to stable maintainers: there is no known security issue here.
A misguided program can set NT and cause the kernel to try and fail
to deliver SIGSEGV, crashing the program. This patch fixes Far Cry
on Wine: https://bugs.winehq.org/show_bug.cgi?id=33275
Reported-by: Anish Bhatt <anish@chelsio.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/395749a5d39a29bd3e4b35899cf3a3c1340e5595.1412189265.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 66463db4fc5605d51c7bb81d009d5bf30a783a2c upstream.
save_xstate_sig()->drop_init_fpu() doesn't look right. setup_rt_frame()
can fail after that, in this case the next setup_rt_frame() triggered
by SIGSEGV won't save fpu simply because the old state was lost. This
obviously mean that fpu won't be restored after sys_rt_sigreturn() from
SIGSEGV handler.
Shift drop_init_fpu() into !failed branch in handle_signal().
Test-case (needs -O2):
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <pthread.h>
#include <assert.h>
volatile double D;
void test(double d)
{
int pid = getpid();
for (D = d; D == d; ) {
/* sys_tkill(pid, SIGHUP); asm to avoid save/reload
* fp regs around "C" call */
asm ("" : : "a"(200), "D"(pid), "S"(1));
asm ("syscall" : : : "ax");
}
printf("ERR!!\n");
}
void sigh(int sig)
{
}
char altstack[4096 * 10] __attribute__((aligned(4096)));
void *tfunc(void *arg)
{
for (;;) {
mprotect(altstack, sizeof(altstack), PROT_READ);
mprotect(altstack, sizeof(altstack), PROT_READ|PROT_WRITE);
}
}
int main(void)
{
stack_t st = {
.ss_sp = altstack,
.ss_size = sizeof(altstack),
.ss_flags = SS_ONSTACK,
};
struct sigaction sa = {
.sa_handler = sigh,
};
pthread_t pt;
sigaction(SIGSEGV, &sa, NULL);
sigaltstack(&st, NULL);
sa.sa_flags = SA_ONSTACK;
sigaction(SIGHUP, &sa, NULL);
pthread_create(&pt, NULL, tfunc, NULL);
test(123.456);
return 0;
}
Reported-by: Bean Anderson <bean@azulsystems.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175713.GA21646@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit df24fb859a4e200d9324e2974229fbb7adf00aef upstream.
Add preempt_disable() + preempt_enable() around math_state_restore() in
__restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin()
can overwrite fpu->state we are going to restore.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175717.GA21649@redhat.com
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ee1b5b165c0a2f04d2107e634e51f05d0eb107de upstream.
Quark x1000 advertises PGE via the standard CPUID method
PGE bits exist in Quark X1000's PTEs. In order to flush
an individual PTE it is necessary to reload CR3 irrespective
of the PTE.PGE bit.
See Quark Core_DevMan_001.pdf section 6.4.11
This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to
crash and burn on this platform.
Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 24223657806a0ebd0ae5c9caaf7b021091889cf2 upstream.
CPUs which should support the RAPL counters according to
Family/Model/Stepping may still issue #GP when attempting to access
the RAPL MSRs. This may happen when Linux is running under KVM and
we are passing-through host F/M/S data, for example. Use rdmsrl_safe
to first access the RAPL_POWER_UNIT MSR; if this fails, do not
attempt to use this PMU.
Signed-off-by: Venkatesh Srinivas <venkateshs@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1394739386-22260-1-git-send-email-venkateshs@google.com
Cc: zheng.z.yan@intel.com
Cc: eranian@google.com
Cc: ak@linux.intel.com
Cc: linux-kernel@vger.kernel.org
[ The patch also silently fixes another bug: rapl_pmu_init() didn't handle the memory alloc failure case previously. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[backport by whissi]
Cc: Thomas D <whissi@whissi.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 03bd4e1f7265548832a76e7919a81f3137c44fd1 upstream.
The following bug can be triggered by hot adding and removing a large number of
xen domain0's vcpus repeatedly:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group
PGD 5a9d5067 PUD 13067 PMD 0
Oops: 0000 [#3] SMP
[...]
Call Trace:
load_balance
? _raw_spin_unlock_irqrestore
idle_balance
__schedule
schedule
schedule_timeout
? lock_timer_base
schedule_timeout_uninterruptible
msleep
lock_device_hotplug_sysfs
online_store
dev_attr_store
sysfs_write_file
vfs_write
SyS_write
system_call_fastpath
Last level cache shared mask is built during CPU up and the
build_sched_domain() routine takes advantage of it to setup
the sched domain CPU topology.
However, llc_shared_mask is not released during CPU disable,
which leads to an invalid sched domainCPU topology.
This patch fix it by releasing the llc_shared_mask correctly
during CPU disable.
Yasuaki also reported that this can happen on real hardware:
https://lkml.org/lkml/2014/7/22/1018
His case is here:
==
Here is an example on my system.
My system has 4 sockets and each socket has 15 cores and HT is
enabled. In this case, each core of sockes is numbered as
follows:
| CPU#
Socket#0 | 0-14 , 60-74
Socket#1 | 15-29, 75-89
Socket#2 | 30-44, 90-104
Socket#3 | 45-59, 105-119
Then llc_shared_mask of CPU#30 has 0x3fff80000001fffc0000000.
It means that last level cache of Socket#2 is shared with
CPU#30-44 and 90-104.
When hot-removing socket#2 and #3, each core of sockets is
numbered as follows:
| CPU#
Socket#0 | 0-14 , 60-74
Socket#1 | 15-29, 75-89
But llc_shared_mask is not cleared. So llc_shared_mask of CPU#30
remains having 0x3fff80000001fffc0000000.
After that, when hot-adding socket#2 and #3, each core of
sockets is numbered as follows:
| CPU#
Socket#0 | 0-14 , 60-74
Socket#1 | 15-29, 75-89
Socket#2 | 30-59
Socket#3 | 90-119
Then llc_shared_mask of CPU#30 becomes
0x3fff8000fffffffc0000000. It means that last level cache of
Socket#2 is shared with CPU#30-59 and 90-104. So the mask has
the wrong value.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Tested-by: Linn Crosetto <linn@hp.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1411547885-48165-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 53b884ac3745353de220d92ef792515c3ae692f0 upstream.
This commit in Linux 3.6:
commit c767a54ba0657e52e6edaa97cbe0b0a8bf1c1655
Author: Joe Perches <joe@perches.com>
Date: Mon May 21 19:50:07 2012 -0700
x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
caused warn_bad_vsyscall to output garbage in the middle of the
line. Revert the bad part of it.
The printk in question isn't actually bare; the level is "%s".
The bug this fixes is purely cosmetic; backports are optional.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/03eac1f24110bbe496ecc12a4df467e0d88466d4.1406330947.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cbace46a9710a480cae51e4611697df5de41713e upstream.
Commit 30919b0bf356 ("x86: avoid low BIOS area when allocating address
space") moved the test for resource allocations that fall within the first
1MB of address space from the PCI-specific path to a generic path, such
that all resource allocations will avoid this area. However, this breaks
ISA cards which need to allocate a memory region within the first 1MB. An
example is the i82365 PCMCIA controller and derivatives like the Ricoh
RF5C296/396 which map part of the PCMCIA socket memory address space into
the first 1MB of system memory address space. They do not work anymore as
no usable memory region exists due to this change:
Intel ISA PCIC probe: Ricoh RF5C296/396 ISA-to-PCMCIA at port 0x3e0 ofs 0x00, 2 sockets
host opts [0]: none
host opts [1]: none
ISA irqs (scanned) = 3,4,5,9,10 status change on irq 10
pcmcia_socket pcmcia_socket1: pccard: PCMCIA card inserted into slot 1
pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean.
pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
pcmcia_socket pcmcia_socket0: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
pcmcia_socket pcmcia_socket0: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
pcmcia_socket pcmcia_socket0: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
pcmcia_socket pcmcia_socket0: cs: memory probe 0x0d0000-0x0dffff: clean.
pcmcia_socket pcmcia_socket0: cs: memory probe 0x0e0000-0x0effff: clean.
pcmcia_socket pcmcia_socket0: cs: memory probe 0x60000000-0x60ffffff: clean.
pcmcia_socket pcmcia_socket0: cs: memory probe 0xa0000000-0xa0ffffff: clean.
pcmcia_socket pcmcia_socket1: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
pcmcia_socket pcmcia_socket1: cs: IO port probe 0xa00-0xaff: clean.
pcmcia_socket pcmcia_socket1: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
pcmcia_socket pcmcia_socket1: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
pcmcia_socket pcmcia_socket1: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
pcmcia_socket pcmcia_socket1: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
pcmcia_socket pcmcia_socket1: cs: memory probe 0x0d0000-0x0dffff: clean.
pcmcia_socket pcmcia_socket1: cs: memory probe 0x0e0000-0x0effff: clean.
pcmcia_socket pcmcia_socket1: cs: memory probe 0x60000000-0x60ffffff: clean.
pcmcia_socket pcmcia_socket1: cs: memory probe 0xa0000000-0xa0ffffff: clean.
pcmcia_socket pcmcia_socket1: cs: memory probe 0x0cc000-0x0effff: excluding 0xe0000-0xeffff
pcmcia_socket pcmcia_socket1: cs: unable to map card memory!
If filtering out the first 1MB is reverted, everything works as expected.
Tested-by: Robert Resch <fli4l@robert.reschpara.de>
Signed-off-by: Christoph Schulz <develop@kristov.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8762e5092828c4dc0f49da5a47a644c670df77f3 upstream.
init_espfix_ap() is currently off by one level when informing hypervisor
that allocated pages will be used for ministacks' page tables.
The most immediate effect of this on a PV guest is that if
'stack_page = __get_free_page()' returns a non-zeroed-out page the hypervisor
will refuse to use it for a page table (which it shouldn't be anyway). This will
result in warnings by both Xen and Linux.
More importantly, a subsequent write to that page (again, by a PV guest) is
likely to result in fatal page fault.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1404926298-5565-1-git-send-email-boris.ostrovsky@oracle.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7209a75d2009dbf7745e2fd354abf25c3deb3ca3 upstream.
This moves the espfix64 logic into native_iret. To make this work,
it gets rid of the native patch for INTERRUPT_RETURN:
INTERRUPT_RETURN on native kernels is now 'jmp native_iret'.
This changes the 16-bit SS behavior on Xen from OOPSing to leaking
some bits of the Xen hypervisor's RSP (I think).
[ hpa: this is a nonzero cost on native, but probably not enough to
measure. Xen needs to fix this in their own code, probably doing
something equivalent to espfix64. ]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/7b8f1d8ef6597cb16ae004a43c56980a7de3cf94.1406129132.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 34273f41d57ee8d854dcd2a1d754cbb546cb548f upstream.
Embedded systems, which may be very memory-size-sensitive, are
extremely unlikely to ever encounter any 16-bit software, so make it
a CONFIG_EXPERT option to turn off support for any 16-bit software
whatsoever.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 197725de65477bc8509b41388157c1a2283542bb upstream.
Make espfix64 a hidden Kconfig option. This fixes the x86-64 UML
build which had broken due to the non-existence of init_espfix_bsp()
in UML: since UML uses its own Kconfig, this option does not appear in
the UML build.
This also makes it possible to make support for 16-bit segments a
configuration option, for the people who want to minimize the size of
the kernel.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e1fe9ed8d2a4937510d0d60e20705035c2609aea upstream.
Sparse warns that the percpu variables aren't declared before they are
defined. Rather than hacking around it, move espfix definitions into
a proper header file.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.
The IRET instruction, when returning to a 16-bit segment, only
restores the bottom 16 bits of the user space stack pointer. This
causes some 16-bit software to break, but it also leaks kernel state
to user space. We have a software workaround for that ("espfix") for
the 32-bit kernel, but it relies on a nonzero stack segment base which
is not available in 64-bit mode.
In checkin:
b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels
we "solved" this by forbidding 16-bit segments on 64-bit kernels, with
the logic that 16-bit support is crippled on 64-bit kernels anyway (no
V86 support), but it turns out that people are doing stuff like
running old Win16 binaries under Wine and expect it to work.
This works around this by creating percpu "ministacks", each of which
is mapped 2^16 times 64K apart. When we detect that the return SS is
on the LDT, we copy the IRET frame to the ministack and use the
relevant alias to return to userspace. The ministacks are mapped
readonly, so if IRET faults we promote #GP to #DF which is an IST
vector and thus has its own stack; we then do the fixup in the #DF
handler.
(Making #GP an IST exception would make the msr_safe functions unsafe
in NMI/MC context, and quite possibly have other effects.)
Special thanks to:
- Andy Lutomirski, for the suggestion of using very small stack slots
and copy (as opposed to map) the IRET frame there, and for the
suggestion to mark them readonly and let the fault promote to #DF.
- Konrad Wilk for paravirt fixup and testing.
- Borislav Petkov for testing help and useful comments.
Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Lutomriski <amluto@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dirk Hohndel <dirk@hohndel.org>
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: comex <comexk@gmail.com>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <stable@vger.kernel.org> # consider after upstream merge
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7ed6fb9b5a5510e4ef78ab27419184741169978a upstream.
This reverts commit fa81511bb0bbb2b1aace3695ce869da9762624ff in
preparation of merging in the proper fix (espfix64).
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8142b215501f8b291a108a202b3a053a265b03dd upstream.
Commit 554086d ("x86_32, entry: Do syscall exit work on badsys
(CVE-2014-4508)") introduced a regression in the x86_32 syscall entry
code, resulting in syscall() not returning proper errors for undefined
syscalls on CPUs supporting the sysenter feature.
The following code:
> int result = syscall(666);
> printf("result=%d errno=%d error=%s\n", result, errno, strerror(errno));
results in:
> result=666 errno=0 error=Success
Obviously, the syscall return value is the called syscall number, but it
should have been an ENOSYS error. When run under ptrace it behaves
correctly, which makes it hard to debug in the wild:
> result=-1 errno=38 error=Function not implemented
The %eax register is the return value register. For debugging via ptrace
the syscall entry code stores the complete register context on the
stack. The badsys handlers only store the ENOSYS error code in the
ptrace register set and do not set %eax like a regular syscall handler
would. The old resume_userspace call chain contains code that clobbers
%eax and it restores %eax from the ptrace registers afterwards. The same
goes for the ptrace-enabled call chain. When ptrace is not used, the
syscall return value is the passed-in syscall number from the untouched
%eax register.
Use %eax as the return value register in syscall_badsys and
sysenter_badsys, like a real syscall handler does, and have the caller
push the value onto the stack for ptrace access.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Link: http://lkml.kernel.org/r/alpine.LNX.2.11.1407221022380.31021@titan.int.lan.stealer.net
Reviewed-and-tested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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