x86/irq: Move irq stacks to percpu hot section

No functional change.

Signed-off-by: Brian Gerst <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Uros Bizjak <ubizjak@gmai

x86/irq: Move irq stacks to percpu hot section

No functional change.

Signed-off-by: Brian Gerst <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Uros Bizjak <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

x86/percpu: Move irq_stack variables next to current_task

Further extend struct pcpu_hot with the hard and soft irq stack
pointers.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by

x86/percpu: Move irq_stack variables next to current_task

Further extend struct pcpu_hot with the hard and soft irq stack
pointers.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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x86/mm/64: Improve stack overflow warnings

Current code has an explicit check for hitting the task stack guard;
but overflowing any of the other stacks will get you a non-descript
general #DF warnin

x86/mm/64: Improve stack overflow warnings

Current code has an explicit check for hitting the task stack guard;
but overflowing any of the other stacks will get you a non-descript
general #DF warning.

Improve matters by using get_stack_info_noinstr() to detetrmine if and
which stack guard page got hit, enabling a better stack warning.

In specific, Michael Wang reported what turned out to be an NMI
exception stack overflow, which is now clearly reported as such:

[] BUG: NMI stack guard page was hit at 0000000085fd977b (stack is 000000003a55b09e..00000000d8cce1a5)

Reported-by: Michael Wang <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Michael Wang <[email protected]>
Link: https://lkml.kernel.org/r/YUTE/[email protected]

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x86/irq/64: Adjust the per CPU irq stack pointer by 8

The per CPU hardirq_stack_ptr contains the pointer to the irq stack in the
form that it is ready to be assigned to [ER]SP so that the first push

x86/irq/64: Adjust the per CPU irq stack pointer by 8

The per CPU hardirq_stack_ptr contains the pointer to the irq stack in the
form that it is ready to be assigned to [ER]SP so that the first push ends
up on the top entry of the stack.

But the stack switching on 64 bit has the following rules:

1) Store the current stack pointer (RSP) in the top most stack entry
to allow the unwinder to link back to the previous stack

2) Set RSP to the top most stack entry

3) Invoke functions on the irq stack

4) Pop RSP from the top most stack entry (stored in #1) so it's back
to the original stack.

That requires all stack switching code to decrement the stored pointer by 8
in order to be able to store the current RSP and then set RSP to that
location. That's a pointless exercise.

Do the -8 adjustment right when storing the pointer and make the data type
a void pointer to avoid confusion vs. the struct irq_stack data type which
is on 64bit only used to declare the backing store. Move the definition
next to the inuse flag so they likely end up in the same cache
line. Sticking them into a struct to enforce it is a seperate change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

x86/dumpstack/64: Add noinstr version of get_stack_info()

The get_stack_info() functionality is needed in the entry code for the
#VC exception handler. Provide a version of it in the .text.noinstr
s

x86/dumpstack/64: Add noinstr version of get_stack_info()

The get_stack_info() functionality is needed in the entry code for the
#VC exception handler. Provide a version of it in the .text.noinstr
section which can be called safely from there.

Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/sev-es: Allocate and map an IST stack for #VC handler

Allocate and map an IST stack and an additional fall-back stack for
the #VC handler. The memory for the stacks is allocated only when
SEV-E

x86/sev-es: Allocate and map an IST stack for #VC handler

Allocate and map an IST stack and an additional fall-back stack for
the #VC handler. The memory for the stacks is allocated only when
SEV-ES is active.

The #VC handler needs to use an IST stack because a #VC exception can be
raised from kernel space with unsafe stack, e.g. in the SYSCALL entry
path.

Since the #VC exception can be nested, the #VC handler switches back to
the interrupted stack when entered from kernel space. If switching back
is not possible, the fall-back stack is used.

Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/entry: Remove DBn stacks

Both #DB itself, as all other IST users (NMI, #MC) now clear DR7 on
entry. Combined with not allowing breakpoints on entry/noinstr/NOKPROBE
text and no single step (EFLA

x86/entry: Remove DBn stacks

Both #DB itself, as all other IST users (NMI, #MC) now clear DR7 on
entry. Combined with not allowing breakpoints on entry/noinstr/NOKPROBE
text and no single step (EFLAGS.TF) inside the #DB handler should guarantee
no nested #DB.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/unwind: Prevent false warnings for non-current tasks

There's some daring kernel code out there which dumps the stack of
another task without first making sure the task is inactive. If the
task

x86/unwind: Prevent false warnings for non-current tasks

There's some daring kernel code out there which dumps the stack of
another task without first making sure the task is inactive. If the
task happens to be running while the unwinder is reading the stack,
unusual unwinder warnings can result.

There's no race-free way for the unwinder to know whether such a warning
is legitimate, so just disable unwinder warnings for all non-current
tasks.

Reviewed-by: Miroslav Benes <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Link: https://lore.kernel.org/r/ec424a2aea1d461eb30cab48a28c6433de2ab784.1587808742.git.jpoimboe@redhat.com

show more ...

x86/dumpstack/64: Don't evaluate exception stacks before setup

Cyrill reported the following crash:

BUG: unable to handle page fault for address: 0000000000001ff0
#PF: supervisor read access in

x86/dumpstack/64: Don't evaluate exception stacks before setup

Cyrill reported the following crash:

BUG: unable to handle page fault for address: 0000000000001ff0
#PF: supervisor read access in kernel mode
RIP: 0010:get_stack_info+0xb3/0x148

It turns out that if the stack tracer is invoked before the exception stack
mappings are initialized in_exception_stack() can erroneously classify an
invalid address as an address inside of an exception stack:

begin = this_cpu_read(cea_exception_stacks); <- 0
end = begin + sizeof(exception stacks);

i.e. any address between 0 and end will be considered as exception stack
address and the subsequent code will then try to derefence the resulting
stack frame at a non mapped address.

end = begin + (unsigned long)ep->size;
==> end = 0x2000

regs = (struct pt_regs *)end - 1;
==> regs = 0x2000 - sizeof(struct pt_regs *) = 0x1ff0

info->next_sp = (unsigned long *)regs->sp;
==> Crashes due to accessing 0x1ff0

Prevent this by checking the validity of the cea_exception_stack base
address and bailing out if it is zero.

Fixes: afcd21dad88b ("x86/dumpstack/64: Use cpu_entry_area instead of orig_ist")
Reported-by: Cyrill Gorcunov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Cyrill Gorcunov <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]

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x86/irq/64: Rename irq_stack_ptr to hardirq_stack_ptr

Preparatory patch to share code with 32bit.

No functional changes.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav

x86/irq/64: Rename irq_stack_ptr to hardirq_stack_ptr

Preparatory patch to share code with 32bit.

No functional changes.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: "Chang S. Bae" <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Nicolai Stange <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Pingfan Liu <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/dumpstack/64: Speedup in_exception_stack()

The current implementation of in_exception_stack() iterates over the
exception stacks array. Most of the time this is an useless exercise, but
even for

x86/dumpstack/64: Speedup in_exception_stack()

The current implementation of in_exception_stack() iterates over the
exception stacks array. Most of the time this is an useless exercise, but
even for the actual use cases (perf and ftrace) it takes at least 2
iterations to get to the NMI stack.

As the exception stacks and the guard pages are page aligned the loop can
be avoided completely.

Add a initial check whether the stack pointer is inside the full exception
stack area and leave early if not.

Create a lookup table which describes the stack area. The table index is
the page offset from the beginning of the exception stacks. So for any
given stack pointer the page offset is computed and a lookup in the
description table is performed. If it is inside a guard page, return. If
not, use the descriptor to fill in the info structure.

The table is filled at compile time and for the !KASAN case the interesting
page descriptors exactly fit into a single cache line. Just the last guard
page descriptor is in the next cacheline, but that should not be accessed
in the regular case.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/exceptions: Split debug IST stack

The debug IST stack is actually two separate debug stacks to handle #DB
recursion. This is required because the CPU starts always at top of stack
on exception e

x86/exceptions: Split debug IST stack

The debug IST stack is actually two separate debug stacks to handle #DB
recursion. This is required because the CPU starts always at top of stack
on exception entry, which means on #DB recursion the second #DB would
overwrite the stack of the first.

The low level entry code therefore adjusts the top of stack on entry so a
secondary #DB starts from a different stack page. But the stack pages are
adjacent without a guard page between them.

Split the debug stack into 3 stacks which are separated by guard pages. The
3rd stack is never mapped into the cpu_entry_area and is only there to
catch triple #DB nesting:

--- top of DB_stack <- Initial stack
--- end of DB_stack
guard page

--- top of DB1_stack <- Top of stack after entering first #DB
--- end of DB1_stack
guard page

--- top of DB2_stack <- Top of stack after entering second #DB
--- end of DB2_stack
guard page

If DB2 would not act as the final guard hole, a second #DB would point the
top of #DB stack to the stack below #DB1 which would be valid and not catch
the not so desired triple nesting.

The backing store does not allocate any memory for DB2 and its guard page
as it is not going to be mapped into the cpu_entry_area.

- Adjust the low level entry code so it adjusts top of #DB with the offset
between the stacks instead of exception stack size.

- Make the dumpstack code aware of the new stacks.

- Adjust the in_debug_stack() implementation and move it into the NMI code
where it belongs. As this is NMI hotpath code, it just checks the full
area between top of DB_stack and bottom of DB1_stack without checking
for the guard page. That's correct because the NMI cannot hit a
stackpointer pointing to the guard page between DB and DB1 stack. Even
if it would, then the NMI operation still is unaffected, but the resume
of the debug exception on the topmost DB stack will crash by touching
the guard page.

[ bp: Make exception_stack_names static const char * const ]

Suggested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: "Chang S. Bae" <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: [email protected]
Cc: Masahiro Yamada <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/dumpstack/64: Use cpu_entry_area instead of orig_ist

The orig_ist[] array is a shadow copy of the IST array in the TSS. The
reason why it exists is that older kernels used two TSS variants with

x86/dumpstack/64: Use cpu_entry_area instead of orig_ist

The orig_ist[] array is a shadow copy of the IST array in the TSS. The
reason why it exists is that older kernels used two TSS variants with
different pointers into the debug stack. orig_ist[] contains the real
starting points.

There is no point anymore to do so because the same information can be
retrieved using the base address of the cpu entry area mapping and the
offsets of the various exception stacks.

No functional change. Preparation for removing orig_ist.

Cc: Josh Poimboeuf <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/exceptions: Make IST index zero based

The defines for the exception stack (IST) array in the TSS are using the
SDM convention IST1 - IST7. That causes all sorts of code to subtract 1 for
array i

x86/exceptions: Make IST index zero based

The defines for the exception stack (IST) array in the TSS are using the
SDM convention IST1 - IST7. That causes all sorts of code to subtract 1 for
array indices related to IST. That's confusing at best and does not provide
any value.

Make the indices zero based and fixup the usage sites. The only code which
needs to adjust the 0 based index is the interrupt descriptor setup which
needs to add 1 now.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: "Chang S. Bae" <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: Dou Liyang <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: [email protected]
Cc: Nicolai Stange <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/dumpstack: Fix off-by-one errors in stack identification

The get_stack_info() function is off-by-one when checking whether an
address is on a IRQ stack or a IST stack. This prevents an overflowe

x86/dumpstack: Fix off-by-one errors in stack identification

The get_stack_info() function is off-by-one when checking whether an
address is on a IRQ stack or a IST stack. This prevents an overflowed
IRQ or IST stack from being dumped properly.

[ tglx: Do the same for 32-bit ]

Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/dumpstack: Unify show_regs()

The 32-bit version uses KERN_EMERG and commit

b0f4c4b32c8e ("bugs, x86: Fix printk levels for panic, softlockups and stack dumps")

changed the 64-bit version to

x86/dumpstack: Unify show_regs()

The 32-bit version uses KERN_EMERG and commit

b0f4c4b32c8e ("bugs, x86: Fix printk levels for panic, softlockups and stack dumps")

changed the 64-bit version to KERN_DEFAULT. The same justification in
that commit that those messages do not belong in the terminal, holds
true for 32-bit also, so make it so.

Make code_bytes static, while at it.

Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack

If the kernel oopses while on the trampoline stack, it will print
"<SYSENTER>" even if SYSENTER is not involved. That is rather confus

x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack

If the kernel oopses while on the trampoline stack, it will print
"<SYSENTER>" even if SYSENTER is not involved. That is rather confusing.

The "SYSENTER" stack is used for a lot more than SYSENTER now. Give it a
better string to display in stack dumps, and rename the kernel code to
match.

Also move the 32-bit code over to the new naming even though it still uses
the entry stack only for SYSENTER.

Signed-off-by: Dave Hansen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

x86/dumpstack: Add get_stack_info() support for the SYSENTER stack

get_stack_info() doesn't currently know about the SYSENTER stack, so
unwinding will fail if we entered the kernel on the SYSENTER s

x86/dumpstack: Add get_stack_info() support for the SYSENTER stack

get_stack_info() doesn't currently know about the SYSENTER stack, so
unwinding will fail if we entered the kernel on the SYSENTER stack
and haven't fully switched off. Teach get_stack_info() about the
SYSENTER stack.

With future patches applied that run part of the entry code on the
SYSENTER stack and introduce an intentional BUG(), I would get:

PANIC: double fault, error_code: 0x0
...
RIP: 0010:do_error_trap+0x33/0x1c0
...
Call Trace:
Code: ...

With this patch, I get:

PANIC: double fault, error_code: 0x0
...
Call Trace:
<SYSENTER>
? async_page_fault+0x36/0x60
? invalid_op+0x22/0x40
? async_page_fault+0x36/0x60
? sync_regs+0x3c/0x40
? sync_regs+0x2e/0x40
? error_entry+0x6c/0xd0
? async_page_fault+0x36/0x60
</SYSENTER>
Code: ...

which is a lot more informative.

Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Laight <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: Eduardo Valentin <[email protected]>
Cc: Greg KH <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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x86/dumpstack: Fix interrupt and exception stack boundary checks

On x86_64, the double fault exception stack is located immediately after
the interrupt stack in memory. This causes confusion in the

x86/dumpstack: Fix interrupt and exception stack boundary checks

On x86_64, the double fault exception stack is located immediately after
the interrupt stack in memory. This causes confusion in the unwinder
when it tries to unwind through an empty interrupt stack, where the
stack pointer points to the address bordering the two stacks. The
unwinder incorrectly thinks it's running on the double fault stack.

Fix this kind of stack border confusion by never considering the
beginning address of an exception or interrupt stack to be part of the
stack.

Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Fixes: 5fe599e02e41 ("x86/dumpstack: Add support for unwinding empty IRQ stacks")
Link: http://lkml.kernel.org/r/bcc142160a5104de5c354c21c394c93a0173943f.1499786555.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>

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x86/debug: Implement __WARN() using UD0

By using "UD0" for WARN()s we remove the function call and its possible
__FILE__ and __LINE__ immediate arguments from the instruction stream.

Total image si

x86/debug: Implement __WARN() using UD0

By using "UD0" for WARN()s we remove the function call and its possible
__FILE__ and __LINE__ immediate arguments from the instruction stream.

Total image size will not change much, what we win in the instruction
stream we'll lose because of the __bug_table entries. Still, saves on
I$ footprint and the total image size does go down a bit.

text data filename
10702123 4530992 defconfig-build/vmlinux.orig
10682460 4530992 defconfig-build/vmlinux.patched

(UML didn't seem to use GENERIC_BUG at all, so remove it)

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>

We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up fro

sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>

We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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x86/dumpstack: Make stack name tags more comprehensible

NMI stack dumps are bracketed by the following tags:

<NMI>
...
<EOE>

The ending tag is kind of confusing if you don't already know wha

x86/dumpstack: Make stack name tags more comprehensible

NMI stack dumps are bracketed by the following tags:

<NMI>
...
<EOE>

The ending tag is kind of confusing if you don't already know what "EOE"
means (end of exception). The same ending tag is also used to mark the
end of all other exceptions' stacks. For example:

<#DF>
...
<EOE>

And similarly, "EOI" is used as the ending tag for interrupts:

<IRQ>
...
<EOI>

Change the tags to be more comprehensible by making them symmetrical and
more XML-esque:

<NMI>
...
</NMI>

<#DF>
...
</#DF>

<IRQ>
...
</IRQ>

Signed-off-by: Josh Poimboeuf <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/180196e3754572540b595bc56b947d43658979a7.1479491159.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>

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x86/dumpstack: Warn on stack recursion

Print a warning if stack recursion is detected.

Use printk_deferred_once() because the unwinder can be called with the
console lock by lockdep via save_stack_

x86/dumpstack: Warn on stack recursion

Print a warning if stack recursion is detected.

Use printk_deferred_once() because the unwinder can be called with the
console lock by lockdep via save_stack_trace().

Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/def18247aafaab480844484398e793f552b79bda.1477496147.git.jpoimboe@redhat.com
[ Unbroke the lines. ]
Signed-off-by: Ingo Molnar <[email protected]>

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x86/dumpstack: Remove raw stack dump

For mostly historical reasons, the x86 oops dump shows the raw stack
values:

...
[registers]
Stack:
ffff880079af7350 ffff880079905400 0000000000000000

x86/dumpstack: Remove raw stack dump

For mostly historical reasons, the x86 oops dump shows the raw stack
values:

...
[registers]
Stack:
ffff880079af7350 ffff880079905400 0000000000000000 ffffc900008f3ae0
ffffffffa0196610 0000000000000001 00010000ffffffff 0000000087654321
0000000000000002 0000000000000000 0000000000000000 0000000000000000
Call Trace:
...

This seems to be an artifact from long ago, and probably isn't needed
anymore. It generally just adds noise to the dump, and it can be
actively harmful because it leaks kernel addresses.

Linus says:

"The stack dump actually goes back to forever, and it used to be
useful back in 1992 or so. But it used to be useful mainly because
stacks were simpler and we didn't have very good call traces anyway. I
definitely remember having used them - I just do not remember having
used them in the last ten+ years.

Of course, it's still true that if you can trigger an oops, you've
likely already lost the security game, but since the stack dump is so
useless, let's aim to just remove it and make games like the above
harder."

This also removes the related 'kstack=' cmdline option and the
'kstack_depth_to_print' sysctl.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/e83bd50df52d8fe88e94d2566426ae40d813bf8f.1477405374.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>

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