On Thu, 03 Dec, at 11:58:33PM, Kosuke Tatsukawa wrote:
> The kernel panics early in boot on a x86_64 server if the eXecute
> Disable (XD) bit is set to disabled in the uEFI firmware. The message
> in the kernel log buffer looks like below.
> ------------------------------------------------------------------------
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc3 #1
> [ 0.000000] 0000000000000000 261c6fa13723be1b ffffffff819b7e40 ffffffff8131f320
> [ 0.000000] ffffffffffffffff ffffffff819b7f30 ffffffff81b261b0 000000000000001c
> [ 0.000000] ffffffff81d77a1c 0000000000000010 00000000be35a000 ffffffffff200000
> [ 0.000000] Call Trace:
> [ 0.000000] [<ffffffff8131f320>] dump_stack+0x44/0x64
> [ 0.000000] [<ffffffff81b261b0>] early_idt_handler_common+0x90/0xd0
> [ 0.000000] [<ffffffff81b2f1c5>] ? setup_arch+0x1f1/0xce0
> [ 0.000000] [<ffffffff81b2f1c5>] ? setup_arch+0x1f1/0xce0
> [ 0.000000] [<ffffffff81b26120>] ? early_idt_handler_array+0x120/0x120
> [ 0.000000] [<ffffffff81b26d81>] start_kernel+0xe6/0x4f0
> [ 0.000000] [<ffffffff81b26120>] ? early_idt_handler_array+0x120/0x120
> [ 0.000000] [<ffffffff81b26120>] ? early_idt_handler_array+0x120/0x120
> [ 0.000000] [<ffffffff81b265ee>] x86_64_start_reservations+0x2a/0x2c
> [ 0.000000] [<ffffffff81b2673c>] x86_64_start_kernel+0x14c/0x16f
> [ 0.000000] RIP 0x80000000be359163
> ------------------------------------------------------------------------
>
> The panic occurs because __early_set_fixmap() called from
> parse_setup_data() unconditionally sets the PTE with FIXMAP_PAGE_NORMAL,
> which contains _PAGE_NX and causes an exception.
>
> This patch modifies __early_set_fixmap() to set _PAGE_NX only when the
> hardware supports it. It also moves the call to x86_configure_nx()
> earlier in setup_arch() before __early_set_fixmap() is first called.
>
> The above problem occurs after __early_set_fixmap() is called from
> parse_setup_data(). However, since setup_olpc_ofw_pgd() can also call
> __early_set_fixmap(), the patch moves the call to x86_configure_nx()
> before that.
>
> Signed-off-by: Kosuke Tatsukawa <tatsu@xxxxxxxxxxxxx>
> ---
> arch/x86/kernel/setup.c | 18 +++++++++---------
> arch/x86/mm/ioremap.c | 3 +++
> 2 files changed, 12 insertions(+), 9 deletions(-)
Could you try booting with the commit 04633df0c43d ("x86/cpu: Call
verify_cpu() after having entered long mode too") instead? It's part
of v4.4-rc1.
Allowing NX to be disabled should be avoided.
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