[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86/xen: Delay get_cpu_cap until stack canary is established
On 03/31/2018 01:38 PM, Jason Andryuk wrote: On Wed, Mar 21, 2018, 5:12 PM Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx <mailto:boris.ostrovsky@xxxxxxxxxx>> wrote: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@xxxxxxxxx <mailto:jandryuk@xxxxxxxxx>> > Applied to for-linus-4.17Thanks. If it's not too late, can this be cc: stable? We can always try ;-) This is 4.15 and 4.16 only, I believe. -boris If not, I'll submit the request after it is in Linus's tree.-Jason _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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