Messages in this thread | | | Subject | Re: [PATCH] x86/xen: Delay get_cpu_cap until stack canary is established | From | Boris Ostrovsky <> | Date | Wed, 21 Mar 2018 17:14:21 -0400 |
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On 03/19/2018 12:58 PM, Jason Andryuk wrote: > Commit 2cc42bac1c79 ("x86-64/Xen: eliminate W+X mappings") introduced a > call to get_cpu_cap, which is fstack-protected. This is works on x86-64 > as commit 4f277295e54c ("x86/xen: init %gs very early to avoid page > faults with stack protector") ensures the stack protector is configured, > but it it did not cover x86-32. > > Delay calling get_cpu_cap until after xen_setup_gdt has initialized the > stack canary. Without this, a 32bit PV machine crashes early > in boot. > (XEN) Domain 0 (vcpu#0) crashed on cpu#0: > (XEN) ----[ Xen-4.6.6-xc x86_64 debug=n Tainted: C ]---- > (XEN) CPU: 0 > (XEN) RIP: e019:[<00000000c10362f8>] > > And the PV kernel IP corresponds to init_scattered_cpuid_features > 0xc10362f8 <+24>: mov %gs:0x14,%eax > > Fixes 2cc42bac1c79 ("x86-64/Xen: eliminate W+X mappings") > > Signed-off-by: Jason Andryuk <jandryuk@gmail.com> >
Applied to for-linus-4.17
-boris
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