If we get a page fault indicating kernel stack overflow, invoke
handle_stack_overflow().  To prevent us from overflowing the stack
again while handling the overflow (because we are likely to have
very little stack space left), call handle_stack_overflow() on the
double-fault stack.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/6d6cf96b3fb9b4c9aa303817e1dc4de0c7c36487.1472603235.git.luto@kernel.org
[ Minor edit. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

Now that the x86 switch_to() uses the standard C calling convention,
the STACK_FRAME_NON_STANDARD() annotation is no longer needed.
Suggested-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-8-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

thread_saved_pc() was using a completely bogus method to get the return
address.  Since switch_to() was previously inlined, there was no sane way
to know where on the stack the return address was stored.  Now with the
frame of a sleeping thread well defined, this can be implemented correctly.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-7-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Instead of setting up a fake pt_regs context, put the kernel thread
function pointer and arg into the unused callee-restored registers
of 'struct fork_frame'.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-6-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Move the low-level context switch code to an out-of-line asm stub instead of
using complex inline asm.  This allows constructing a new stack frame for the
child process to make it seamlessly flow to ret_from_fork without an extra
test and branch in __switch_to().  It also improves code generation for
__schedule() by using the C calling convention instead of clobbering all
registers.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-5-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add 'struct inactive_task_frame', which defines the layout of the stack for
a sleeping process.  For now, the only defined field is the BP register
(frame pointer).
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-4-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

switch_to() no longer saves EFLAGS, so it's bogus to look for it on the
stack.  Set it to zero like 32-bit.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Wessel <jason.wessel@windriver.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/1471106302-10159-3-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Match 64-bit and set gdb_regs[GDB_PC] to zero.  thread.ip is always the
same point in the scheduler (except for newly forked processes), and will
be removed in a future patch.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Wessel <jason.wessel@windriver.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/1471106302-10159-2-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When function graph tracing is enabled, print_context_stack_bp() can
report return_to_handler() as an unreliable address, which is confusing
and misleading: return_to_handler() is really only useful as a hint for
debugging, whereas print_context_stack_bp() users only care about the
actual 'reliable' call path.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c51aef578d8027791b38d2ad9bac0c7f499fde91.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When function graph tracing is enabled for a function, its return
address on the stack is replaced with the address of an ftrace handler
(return_to_handler).

Currently 'return_to_handler' can be reported as reliable.  That's not
ideal, and can actually be misleading.  When saving or dumping the
stack, you normally only care about what led up to that point (the call
path), rather than what will happen in the future (the return path).

That's especially true in the non-oops stack trace case, which isn't
used for debugging.  For example, in a perf profiling operation,
reporting return_to_handler() in the trace would just be confusing.

And in the oops case, where debugging is important, "unreliable" is also
more appropriate there because it serves as a hint that graph tracing
was involved, instead of trying to imply that return_to_handler() was
the real caller.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f8af15749c7d632d3e7f815995831d5b7f82950d.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Use the more reliable version of ftrace_graph_ret_addr() so we no longer
have to worry about the unwinder getting out of sync with the function
graph ret_stack index, which can happen if the unwinder skips any frames
before calling ftrace_graph_ret_addr().

This fixes this issue (and several others like it):

  $ cat /proc/self/stack
  [<ffffffff810489a2>] save_stack_trace_tsk+0x22/0x40
  [<ffffffff81311a89>] proc_pid_stack+0xb9/0x110
  [<ffffffff813127c4>] proc_single_show+0x54/0x80
  [<ffffffff812be088>] seq_read+0x108/0x3e0
  [<ffffffff812923d7>] __vfs_read+0x37/0x140
  [<ffffffff812929d9>] vfs_read+0x99/0x140
  [<ffffffff81293f28>] SyS_read+0x58/0xc0
  [<ffffffff818af97c>] entry_SYSCALL_64_fastpath+0x1f/0xbd
  [<ffffffffffffffff>] 0xffffffffffffffff

  $ echo function_graph > /sys/kernel/debug/tracing/current_tracer

  $ cat /proc/self/stack
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff810394cc>] print_context_stack+0xfc/0x100
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff8103891b>] dump_trace+0x12b/0x350
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff810489a2>] save_stack_trace_tsk+0x22/0x40
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff81311a89>] proc_pid_stack+0xb9/0x110
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff813127c4>] proc_single_show+0x54/0x80
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff812be088>] seq_read+0x108/0x3e0
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff812923d7>] __vfs_read+0x37/0x140
  [<ffffffff818b2428>] return_to_handler+0x0/0x27
  [<ffffffff812929d9>] vfs_read+0x99/0x140
  [<ffffffffffffffff>] 0xffffffffffffffff

Enabling function graph tracing causes the stack trace to change in two
ways:

First, the real call addresses are confusingly interspersed with
'return_to_handler' addresses.  This issue will be fixed by the next
patch.

Second, the stack trace is offset by two frames, because the unwinder
skipped the first two frames and got out of sync with the ret_stack
index.  This patch fixes this issue.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a6d623e36f8d08f9a17bd74d804d201177a23afd.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Convert print_context_stack() and print_context_stack_bp() to use the
arch-independent ftrace_graph_ret_addr() helper.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/56ec97cafc1bf2e34d1119e6443d897db406da86.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When function graph tracing is enabled for a function, ftrace modifies
the stack by replacing the original return address with the address of a
hook function (return_to_handler).

Stack unwinders need a way to get the original return address.  Add an
arch-independent helper function for that named ftrace_graph_ret_addr().

This adds two variations of the function: one depends on
HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, and the other relies on an index state
variable.

The former is recommended because, in some cases, the latter can cause
problems when the unwinder skips stack frames.  It can get out of sync
with the ret_stack index and wrong addresses can be reported for the
stack trace.

Once all arches have been ported to use
HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, we can get rid of the distinction.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/36bd90f762fc5e5af3929e3797a68a64906421cf.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Storing this value will help prevent unwinders from getting out of sync
with the function graph tracer ret_stack.  Now instead of needing a
stateful iterator, they can compare the return address pointer to find
the right ret_stack entry.

Note that an array of 50 ftrace_ret_stack structs is allocated for every
task.  So when an arch implements this, it will add either 200 or 400
bytes of memory usage per task (depending on whether it's a 32-bit or
64-bit platform).
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This saves some memory when HAVE_FUNCTION_GRAPH_FP_TEST isn't defined.
On x86_64 with newer versions of gcc which have -mfentry, it saves 400
bytes per task.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5c7747d9ea7b5cb47ef0a8ce8a6cea6bf7aa94bf.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Make HAVE_FUNCTION_GRAPH_FP_TEST a normal define, independent from
kconfig.  This removes some config file pollution and simplifies the
checking for the fp test.
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2c4e5f05054d6d367f702fd153af7a0109dd5c81.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This allows x86_64 kernels to enable vmapped stacks by setting
HAVE_ARCH_VMAP_STACK=y - which enables the CONFIG_VMAP_STACK=y
high level Kconfig option.

There are a couple of interesting bits:

First, x86 lazily faults in top-level paging entries for the vmalloc
area.  This won't work if we get a page fault while trying to access
the stack: the CPU will promote it to a double-fault and we'll die.
To avoid this problem, probe the new stack when switching stacks and
forcibly populate the pgd entry for the stack when switching mms.

Second, once we have guard pages around the stack, we'll want to
detect and handle stack overflow.

I didn't enable it on x86_32.  We'd need to rework the double-fault
code a bit and I'm concerned about running out of vmalloc virtual
addresses under some workloads.

This patch, by itself, will behave somewhat erratically when the
stack overflows while RSP is still more than a few tens of bytes
above the bottom of the stack.  Specifically, we'll get #PF and make
it to no_context and them oops without reliably triggering a
double-fault, and no_context doesn't know about stack overflows.
The next patch will improve that case.

Thank you to Nadav and Brian for helping me pay enough attention to
the SDM to hopefully get this right.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c88f3e2920b18e6cc621d772a04a62c06869037e.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

If we're using CONFIG_VMAP_STACK=y and we manage to point an sg entry
at the stack, then either the sg page will be in highmem or sg_virt()
will return the direct-map alias.  In neither case will the existing
check_for_stack() implementation realize that it's a stack page.

Fix it by explicitly checking for stack pages.

This has no effect by itself.  It's broken out for ease of review.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/448460622731312298bf19dcbacb1606e75de7a9.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

If CONFIG_VMAP_STACK=y is selected, kernel stacks are allocated with
__vmalloc_node_range().

Grsecurity has had a similar feature (called GRKERNSEC_KSTACKOVERFLOW=y)
for a long time.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14c07d4fd173a5b117f51e8b939f9f4323e39899.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

The comment probably meant some old AMD64 incarnation which most likely
never saw the light of day. STAR and LSTAR are two different registers
and STAR sets CS/SS(DS) selectors for *all* modes, not only 32-bit.

So simply remove that comment.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160823172356.15879-1-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Pull two parisc fixes from Helge Deller:
 "The first patch ensures that the high-res cr16 clocksource (which was
  added in kernel 4.7) gets choosen as default clocksource for parisc.

  The second patch moves the #define of EREFUSED down inside errno.h and
  thus unbreaks building the gccgo compiler"

* 'parisc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix order of EREFUSED define in errno.h
  parisc: Fix automatic selection of cr16 clocksource

This is an entirely new driver instead of yet another set of patches
to sb_edac.c because:

1) Mapping from PCI devices to socket/memory controller is significantly
   different. Skylake scatters devices on a socket across a number of
   PCI buses.
2) There is an extra level of interleaving via the "mcroute" register
   that would be a little messy to squeeze into the old driver.
3) Validation is getting too expensive. Changes to sb_edac need to
   be checked against Sandy Bridge, Ivy Bridge, Haswell, Broadwell and
   Knights Landing.
Acked-by: NAristeu Rozanski <aris@redhat.com>
Acked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When building gccgo in userspace, errno.h gets parsed and the go include file
sysinfo.go is generated.

Since EREFUSED is defined to the same value as ECONNREFUSED, and ECONNREFUSED
is defined later on in errno.h, this leads to go complaining that EREFUSED
isn't defined yet.

Fix this trivial problem by moving the define of EREFUSED down after
ECONNREFUSED in errno.h (and clean up the indenting while touching this line).
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

Commit 54b66800 (parisc: Add native high-resolution sched_clock()
implementation) added support to use the CPU-internal cr16 counters as reliable
clocksource with the help of HAVE_UNSTABLE_SCHED_CLOCK.

Sadly the commit missed to remove the hack which prevented cr16 to become the
default clocksource even on SMP systems.
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.7+

The kernel test robot reported a usercopy failure in the new hardened
sanity checks, due to a page-crossing copy of the FPU state into the
task structure.

This happened because the kernel test robot was testing with SLOB, which
doesn't actually do the required book-keeping for slab allocations, and
as a result the hardening code didn't realize that the task struct
allocation was one single allocation - and the sanity checks fail.

Since SLOB doesn't even claim to support hardening (and you really
shouldn't use it), the straightforward solution is to just make the
usercopy hardening code depend on the allocator supporting it.
Reported-by: Nkernel test robot <xiaolong.ye@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull i2c fixes from Wolfram Sang:
 "I2C has some pretty standard driver bugfixes and one minor cleanup"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: meson: Use complete() instead of complete_all()
  i2c: brcmstb: Use complete() instead of complete_all()
  i2c: bcm-kona: Use complete() instead of complete_all()
  i2c: bcm-iproc: Use complete() instead of complete_all()
  i2c: at91: fix support of the "alternative command" feature
  i2c: ocores: add missed clk_disable_unprepare() on failure paths
  i2c: cros-ec-tunnel: Fix usage of cros_ec_cmd_xfer()
  i2c: mux: demux-pinctrl: properly roll back when adding adapter fails

Pull device mapper fixes from Mike Snitzer:

 - a stable fix for DM round robin multipath path selector to disable
   preemption before using this_cpu_ptr()

 - a slight increase in DM crypt's mempool reserves to make swap ontop
   of DM crypt more performant

 - a few DM raid fixes to issues found while testing changes that were
   merged in v4.8-rc1

* tag 'dm-4.8-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm raid: support raid0 with missing metadata devices
  dm raid: enhance attempt_restore_of_faulty_devices() to support more devices
  dm raid: fix restoring of failed devices regression
  dm raid: fix frozen recovery regression
  dm crypt: increase mempool reserve to better support swapping
  dm round robin: do not use this_cpu_ptr() without having preemption disabled

Pull SCSI fixes from James Bottomley:
 "Six fairly small fixes.  The ipr, mpt3sas and ses ones all trigger
  oopses.  The megaraid one fixes an attach failure on io mapped only
  cards, the fcoe one is an obvious problem in the error path and the
  aacraid one is a theoretical security issue (ability to trick the
  kernel into a buffer overrun)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  ses: Fix racy cleanup of /sys in remove_dev()
  mpt3sas: Fix resume on WarpDrive flash cards
  ipr: Fix sync scsi scan
  megaraid_sas: Fix probing cards without io port
  aacraid: Check size values after double-fetch from user
  fcoe: Use kfree_skb() instead of kfree()

Pull USB fixes from Greg KH:
 "Here are a number of USB fixes for reported issues for your tree.

  The normal amount of gadget fixes, xhci fixes, new device ids, and a
  few other minor things.  All of them have been in linux-next for a
  while, the full details are in the shortlog below"

* tag 'usb-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (43 commits)
  xhci: don't dereference a xhci member after removing xhci
  usb: xhci: Fix panic if disconnect
  xhci: really enqueue zero length TRBs.
  xhci: always handle "Command Ring Stopped" events
  cdc-acm: fix wrong pipe type on rx interrupt xfers
  usb: misc: usbtest: add fix for driver hang
  usb: dwc3: gadget: stop processing on HWO set
  usb: dwc3: don't set last bit for ISOC endpoints
  usb: gadget: rndis: free response queue during REMOTE_NDIS_RESET_MSG
  usb: udc: core: fix error handling
  usb: gadget: fsl_qe_udc: off by one in setup_received_handle()
  usb/gadget: fix gadgetfs aio support.
  usb: gadget: composite: Fix return value in case of error
  usb: gadget: uvc: Fix return value in case of error
  usb: gadget: fix check in sync read from ep in gadgetfs
  usb: misc: usbtest: usbtest_do_ioctl may return positive integer
  usb: dwc3: fix missing platform_set_drvdata() in dwc3_of_simple_probe()
  usb: phy: omap-otg: Fix missing platform_set_drvdata() in omap_otg_probe()
  usb: gadget: configfs: add mutex lock before unregister gadget
  usb: gadget: u_ether: fix dereference after null check coverify warning
  ...

Merge tag 'xfs-iomap-for-linus-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs and iomap fixes from Dave Chinner:
 "Changes in this update:

  Regression fixes for XFS changes introduce in 4.8-rc1:
   - buffer IO accounting assert failure
   - ENOSPC block accounting reservation issue
   - DAX IO path page cache invalidation fix
   - rmapbt on-disk block count in agf
   - correct classification of rmap block type when updating AGFL.
   - iomap support for attribute fork mapping

  Regression fixes for iomap infrastructure in 4.8-rc1:
   - fiemap: honor FIEMAP_FLAG_SYNC
   - fiemap: implement FIEMAP_FLAG_XATTR support to fix XFS regression
   - make mark_page_accessed and pagefault_disable usage consistent with
     other IO paths"

* tag 'xfs-iomap-for-linus-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: remove OWN_AG rmap when allocating a block from the AGFL
  xfs: (re-)implement FIEMAP_FLAG_XATTR
  xfs: simplify xfs_file_iomap_begin
  iomap: mark ->iomap_end as optional
  iomap: prepare iomap_fiemap for attribute mappings
  iomap: fiemap should honor the FIEMAP_FLAG_SYNC flag
  iomap: remove superflous pagefault_disable from iomap_write_actor
  iomap: remove superflous mark_page_accessed from iomap_write_actor
  xfs: store rmapbt block count in the AGF
  xfs: don't invalidate whole file on DAX read/write
  xfs: fix bogus space reservation in xfs_iomap_write_allocate
  xfs: don't assert fail on non-async buffers on ioacct decrement

Merge tag 'hwmon-for-linus-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "Fix a bug in it87 driver and URLs in ftsteutates driver"

* tag 'hwmon-for-linus-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (ftsteutates) Correct ftp urls in driver documentation
  hwmon: (it87) Features mask must be 32 bit wide

Pull more drm fixes from Dave Airlie:
 "Daniel pointed out I'd missed some i915 fixes, and I also found a
  single etnaviv fix I missed.

  So here they are"

* tag 'drm-fixes-for-4.8-rc3-2' of git://people.freedesktop.org/~airlied/linux:
  drm/etnaviv: take GPU lock later in the submit process
  drm/i915: Fix modeset handling during gpu reset, v5.
  drm/i915: fix aliasing_ppgtt leak
  drm/i915: fix WaInsertDummyPushConstPs
  drm/i915: Fix iboost setting for SKL Y/U DP DDI buffer translation entry 2
  drm/i915/gen9: Give one extra block per line for SKL plane WM calculations
  drm/i915: Acquire audio powerwell for HD-Audio registers
  drm/i915: Add missing rpm wakelock to GGTT pread
  drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
  drm/i915: Clean up the extra RPM ref on CHV with i915.enable_rc6=0
  drm/i915: Program iboost settings for HDMI/DVI on SKL
  drm/i915: Fix iboost setting for DDI with 4 lanes on SKL
  drm/i915: Handle ENOSPC after failing to insert a mappable node
  drm/i915: Flush GT idle status upon reset

Pull DeviceTree fixes from Rob Herring:

 - a couple of DT node ref counting fixes

 - fix __unflatten_device_tree for PPC PCI hotplug case

 - rework marking irq controllers as OF_POPULATED in cases where real
   driver is used.

 - disable of_platform_default_populate_init on PPC.  The change in
   initcall order causes problems which need to be sorted out later.

* tag 'devicetree-fixes-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  of: fix reference counting in of_graph_get_endpoint_by_regs
  of/platform: disable the of_platform_default_populate_init() for all the ppc boards
  ARM: imx6: mark GPC node as not populated after irq init to probe pm domain driver
  of/irq: Mark interrupt controllers as populated before initialisation
  drivers/of: Validate device node in __unflatten_device_tree()
  of: Delete an unnecessary check before the function call "of_node_put"

Pull documentation fixes from Jonathan Corbet:
 "Three small fixes for Sphinx-formatted documentation generation"

* tag '4.8-doc-fixes' of git://git.lwn.net/linux:
  doc-rst: customize RTD theme, drop padding of inline literal
  docs: kernel-documentation: remove some highlight directives
  docs: Set the Sphinx default highlight language to "guess"

Collection of i915 fixes.

* tag 'drm-intel-fixes-2016-08-15' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Fix modeset handling during gpu reset, v5.
  drm/i915: fix aliasing_ppgtt leak
  drm/i915: fix WaInsertDummyPushConstPs
  drm/i915: Fix iboost setting for SKL Y/U DP DDI buffer translation entry 2
  drm/i915/gen9: Give one extra block per line for SKL plane WM calculations
  drm/i915: Acquire audio powerwell for HD-Audio registers
  drm/i915: Add missing rpm wakelock to GGTT pread
  drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
  drm/i915: Clean up the extra RPM ref on CHV with i915.enable_rc6=0
  drm/i915: Program iboost settings for HDMI/DVI on SKL
  drm/i915: Fix iboost setting for DDI with 4 lanes on SKL
  drm/i915: Handle ENOSPC after failing to insert a mappable node
  drm/i915: Flush GT idle status upon reset

Single GPU recovery fix
* 'drm-etnaviv-fixes' of git://git.pengutronix.de/git/lst/linux:
  drm/etnaviv: take GPU lock later in the submit process

Pull x86 fixes from Ingo Molnar:
 "An initrd microcode loading fix, and an SMP bootup topology setup fix
  to resolve crashes on SGI/UV systems if the BIOS is configured in a
  certain way"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smp: Fix __max_logical_packages value setup
  x86/microcode/AMD: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y