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  1. 23 Mar, 2018 2 commits
  3. 20 Mar, 2018 4 commits
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  13. 09 Mar, 2018 1 commit
    • Francis Deslauriers's avatar
      x86/kprobes: Fix kernel crash when probing .entry_trampoline code · c07a8f8b
      Francis Deslauriers authored 
      Disable the kprobe probing of the entry trampoline:

.entry_trampoline is a code area that is used to ensure page table
isolation between userspace and kernelspace.

At the beginning of the execution of the trampoline, we load the
kernel's CR3 register. This has the effect of enabling the translation
of the kernel virtual addresses to physical addresses. Before this
happens most kernel addresses can not be translated because the running
process' CR3 is still used.

If a kprobe is placed on the trampoline code before that change of the
CR3 register happens the kernel crashes because int3 handling pages are
not accessible.

To fix this, add the .entry_trampoline section to the kprobe blacklist
to prohibit the probing of code before all the kernel pages are
accessible.
Signed-off-by: default avatarFrancis Deslauriers <francis.deslauriers@efficios.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.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: mathieu.desnoyers@efficios.com
Cc: mhiramat@kernel.org
Link: http://lkml.kernel.org/r/1520565492-4637-2-git-send-email-francis.deslauriers@efficios.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      c07a8f8b
  15. 08 Mar, 2018 10 commits
  17. 07 Mar, 2018 7 commits
  19. 01 Mar, 2018 1 commit
    • Thomas Gleixner's avatar
      x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table · 945fd17a
      Thomas Gleixner authored 
      The separation of the cpu_entry_area from the fixmap missed the fact that
on 32bit non-PAE kernels the cpu_entry_area mapping might not be covered in
initial_page_table by the previous synchronizations.

This results in suspend/resume failures because 32bit utilizes initial page
table for resume. The absence of the cpu_entry_area mapping results in a
triple fault, aka. insta reboot.

With PAE enabled this works by chance because the PGD entry which covers
the fixmap and other parts incindentally provides the cpu_entry_area
mapping as well.

Synchronize the initial page table after setting up the cpu entry
area. Instead of adding yet another copy of the same code, move it to a
function and invoke it from the various places.

It needs to be investigated if the existing calls in setup_arch() and
setup_per_cpu_areas() can be replaced by the later invocation from
setup_cpu_entry_areas(), but that's beyond the scope of this fix.

Fixes: 92a0f81d ("x86/cpu_entry_area: Move it out of the fixmap")
Reported-by: default avatarWoody Suwalski <terraluna977@gmail.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarWoody Suwalski <terraluna977@gmail.com>
Cc: William Grant <william.grant@canonical.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1802282137290.1392@nanos.tec.linutronix.de
      945fd17a
  21. 28 Feb, 2018 2 commits
  23. 23 Feb, 2018 2 commits
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