linux.git/arch, branch v3.18.72

ARC: Re-enable MMU upon Machine Check exception

2017-09-27T08:57:21+00:00

commit 1ee55a8f7f6b7ca4c0c59e0b4b4e3584a085c2d3 upstream.

I recently came upon a scenario where I would get a double fault
machine check exception tiriggered by a kernel module.
However the ensuing crash stacktrace (ksym lookup) was not working
correctly.

Turns out that machine check auto-disables MMU while modules are allocated
in kernel vaddr spapce.

This patch re-enables the MMU before start printing the stacktrace
making stacktracing of modules work upon a fatal exception.

Signed-off-by: Jose Abreu 
Reviewed-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
[vgupta: moved code into low level handler to avoid in 2 places]
Signed-off-by: Greg Kroah-Hartman

powerpc: Fix DAR reporting when alignment handler faults

2017-09-27T08:57:19+00:00

commit f9effe925039cf54489b5c04e0d40073bb3a123d upstream.

Anton noticed that if we fault part way through emulating an unaligned
instruction, we don't update the DAR to reflect that.

The DAR value is eventually reported back to userspace as the address
in the SEGV signal, and if userspace is using that value to demand
fault then it can be confused by us not setting the value correctly.

This patch is ugly as hell, but is intended to be the minimal fix and
back ports easily.

Signed-off-by: Michael Ellerman 
Reviewed-by: Paul Mackerras 
Signed-off-by: Greg Kroah-Hartman

ARM: 8692/1: mm: abort uaccess retries upon fatal signal

2017-09-13T21:03:47+00:00

commit 746a272e44141af24a02f6c9b0f65f4c4598ed42 upstream.

When there's a fatal signal pending, arm's do_page_fault()
implementation returns 0. The intent is that we'll return to the
faulting userspace instruction, delivering the signal on the way.

However, if we take a fatal signal during fixing up a uaccess, this
results in a return to the faulting kernel instruction, which will be
instantly retried, resulting in the same fault being taken forever. As
the task never reaches userspace, the signal is not delivered, and the
task is left unkillable. While the task is stuck in this state, it can
inhibit the forward progress of the system.

To avoid this, we must ensure that when a fatal signal is pending, we
apply any necessary fixup for a faulting kernel instruction. Thus we
will return to an error path, and it is up to that code to make forward
progress towards delivering the fatal signal.

Signed-off-by: Mark Rutland 
Reviewed-by: Steve Capper 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

x86/tools: Fix gcc-7 warning in relocs.c

2017-09-02T05:05:46+00:00

commit 7ebb916782949621ff6819acf373a06902df7679 upstream.

gcc-7 warns:

In file included from arch/x86/tools/relocs_64.c:17:0:
arch/x86/tools/relocs.c: In function ‘process_64’:
arch/x86/tools/relocs.c:953:2: warning: argument 1 null where non-null expected [-Wnonnull]
  qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from arch/x86/tools/relocs.h:6:0,
                 from arch/x86/tools/relocs_64.c:1:
/usr/include/stdlib.h:741:13: note: in a call to function ‘qsort’ declared here
 extern void qsort

This happens because relocs16 is not used for ELF_BITS == 64,
so there is no point in trying to sort it.

Make the sort_relocs(&relocs16) call 32bit only.

Signed-off-by: Markus Trippelsdorf 
Link: http://lkml.kernel.org/r/20161215124513.GA289@x4
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86-64: Handle PC-relative relocations on per-CPU data

2017-09-02T05:05:46+00:00

commit 6d24c5f72dfb26e5fa7f02fa9266dfdbae41adba upstream.

This is in preparation of using RIP-relative addressing in many of the
per-CPU accesses.

Signed-off-by: Jan Beulich 
Link: http://lkml.kernel.org/r/5458A15A0200007800044A9A@mail.emea.novell.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

arm64: fpsimd: Prevent registers leaking across exec

2017-09-02T05:05:46+00:00

commit 096622104e14d8a1db4860bd557717067a0515d2 upstream.

There are some tricky dependencies between the different stages of
flushing the FPSIMD register state during exec, and these can race
with context switch in ways that can cause the old task's regs to
leak across.  In particular, a context switch during the memset() can
cause some of the task's old FPSIMD registers to reappear.

Disabling preemption for this small window would be no big deal for
performance: preemption is already disabled for similar scenarios
like updating the FPSIMD registers in sigreturn.

So, instead of rearranging things in ways that might swap existing
subtle bugs for new ones, this patch just disables preemption
around the FPSIMD state flushing so that races of this type can't
occur here.  This brings fpsimd_flush_thread() into line with other
code paths.

Fixes: 674c242c9323 ("arm64: flush FP/SIMD state correctly after execve()")
Reviewed-by: Ard Biesheuvel 
Signed-off-by: Dave Martin 
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

arm64: flush FP/SIMD state correctly after execve()

2017-09-02T05:05:46+00:00

commit 674c242c9323d3c293fc4f9a3a3a619fe3063290 upstream.

When a task calls execve(), its FP/SIMD state is flushed so that
none of the original program state is observeable by the incoming
program.

However, since this flushing consists of setting the in-memory copy
of the FP/SIMD state to all zeroes, the CPU field is set to CPU 0 as
well, which indicates to the lazy FP/SIMD preserve/restore code that
the FP/SIMD state does not need to be reread from memory if the task
is scheduled again on CPU 0 without any other tasks having entered
userland (or used the FP/SIMD in kernel mode) on the same CPU in the
mean time. If this happens, the FP/SIMD state of the old program will
still be present in the registers when the new program starts.

So set the CPU field to the invalid value of NR_CPUS when performing
the flush, by calling fpsimd_flush_task_state().

Reported-by: Chunyan Zhang 
Reported-by: Janet Liu 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

x86/io: Add "memory" clobber to insb/insw/insl/outsb/outsw/outsl

2017-09-02T05:05:46+00:00

commit 7206f9bf108eb9513d170c73f151367a1bdf3dbf upstream.

The x86 version of insb/insw/insl uses an inline assembly that does
not have the target buffer listed as an output. This can confuse
the compiler, leading it to think that a subsequent access of the
buffer is uninitialized:

  drivers/net/wireless/wl3501_cs.c: In function ‘wl3501_mgmt_scan_confirm’:
  drivers/net/wireless/wl3501_cs.c:665:9: error: ‘sig.status’ is used uninitialized in this function [-Werror=uninitialized]
  drivers/net/wireless/wl3501_cs.c:668:12: error: ‘sig.cap_info’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  drivers/net/sb1000.c: In function 'sb1000_rx':
  drivers/net/sb1000.c:775:9: error: 'st[0]' is used uninitialized in this function [-Werror=uninitialized]
  drivers/net/sb1000.c:776:10: error: 'st[1]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  drivers/net/sb1000.c:784:11: error: 'st[1]' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I tried to mark the exact input buffer as an output here, but couldn't
figure it out. As suggested by Linus, marking all memory as clobbered
however is good enough too. For the outs operations, I also add the
memory clobber, to force the input to be written to local variables.
This is probably already guaranteed by the "asm volatile", but it can't
hurt to do this for symmetry.

Suggested-by: Linus Torvalds 
Signed-off-by: Arnd Bergmann 
Acked-by: Linus Torvalds 
Cc: Borislav Petkov 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Tom Lendacky 
Link: http://lkml.kernel.org/r/20170719125310.2487451-5-arnd@arndb.de
Link: https://lkml.org/lkml/2017/7/12/605
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

arm64: mm: abort uaccess retries upon fatal signal

2017-09-02T05:05:45+00:00

commit 289d07a2dc6c6b6f3e4b8a62669320d99dbe6c3d upstream.

When there's a fatal signal pending, arm64's do_page_fault()
implementation returns 0. The intent is that we'll return to the
faulting userspace instruction, delivering the signal on the way.

However, if we take a fatal signal during fixing up a uaccess, this
results in a return to the faulting kernel instruction, which will be
instantly retried, resulting in the same fault being taken forever. As
the task never reaches userspace, the signal is not delivered, and the
task is left unkillable. While the task is stuck in this state, it can
inhibit the forward progress of the system.

To avoid this, we must ensure that when a fatal signal is pending, we
apply any necessary fixup for a faulting kernel instruction. Thus we
will return to an error path, and it is up to that code to make forward
progress towards delivering the fatal signal.

Cc: Catalin Marinas 
Cc: Laura Abbott 
Reviewed-by: Steve Capper 
Tested-by: Steve Capper 
Reviewed-by: James Morse 
Tested-by: James Morse 
Signed-off-by: Mark Rutland 
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

ARM: 8632/1: ftrace: fix syscall name matching

2017-08-11T16:30:16+00:00

[ Upstream commit 270c8cf1cacc69cb8d99dea812f06067a45e4609 ]

ARM has a few system calls (most notably mmap) for which the names of
the functions which are referenced in the syscall table do not match the
names of the syscall tracepoints.  As a consequence of this, these
tracepoints are not made available.  Implement
arch_syscall_match_sym_name to fix this and allow tracing even these
system calls.

Signed-off-by: Rabin Vincent 
Signed-off-by: Russell King 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman