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| author | Zhenzhong Duan <zhenzhong.duan@oracle.com> | 2019-07-14 17:15:32 +0800 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2019-07-17 08:09:59 +0200 |
| commit | b23e5844dfe78a80ba672793187d3f52e4b528d7 (patch) | |
| tree | e5ee85eac34d65720e2ce7189ae8adc3fcbd123c /arch/x86/include/asm/traps.h | |
| parent | bef6e0ae7420bfddfb150dda529bbe835f87b9f2 (diff) | |
| download | linux-b23e5844dfe78a80ba672793187d3f52e4b528d7.tar.gz linux-b23e5844dfe78a80ba672793187d3f52e4b528d7.tar.bz2 linux-b23e5844dfe78a80ba672793187d3f52e4b528d7.zip | |
xen/pv: Fix a boot up hang revealed by int3 self test
Commit 7457c0da024b ("x86/alternatives: Add int3_emulate_call()
selftest") is used to ensure there is a gap setup in int3 exception stack
which could be used for inserting call return address.
This gap is missed in XEN PV int3 exception entry path, then below panic
triggered:
[ 0.772876] general protection fault: 0000 [#1] SMP NOPTI
[ 0.772886] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0+ #11
[ 0.772893] RIP: e030:int3_magic+0x0/0x7
[ 0.772905] RSP: 3507:ffffffff82203e98 EFLAGS: 00000246
[ 0.773334] Call Trace:
[ 0.773334] alternative_instructions+0x3d/0x12e
[ 0.773334] check_bugs+0x7c9/0x887
[ 0.773334] ? __get_locked_pte+0x178/0x1f0
[ 0.773334] start_kernel+0x4ff/0x535
[ 0.773334] ? set_init_arg+0x55/0x55
[ 0.773334] xen_start_kernel+0x571/0x57a
For 64bit PV guests, Xen's ABI enters the kernel with using SYSRET, with
%rcx/%r11 on the stack. To convert back to "normal" looking exceptions,
the xen thunks do 'xen_*: pop %rcx; pop %r11; jmp *'.
E.g. Extracting 'xen_pv_trap xenint3' we have:
xen_xenint3:
pop %rcx;
pop %r11;
jmp xenint3
As xenint3 and int3 entry code are same except xenint3 doesn't generate
a gap, we can fix it by using int3 and drop useless xenint3.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'arch/x86/include/asm/traps.h')
| -rw-r--r-- | arch/x86/include/asm/traps.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 7d6f3f3fad78..f2bd284abc16 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -40,7 +40,7 @@ asmlinkage void simd_coprocessor_error(void); asmlinkage void xen_divide_error(void); asmlinkage void xen_xennmi(void); asmlinkage void xen_xendebug(void); -asmlinkage void xen_xenint3(void); +asmlinkage void xen_int3(void); asmlinkage void xen_overflow(void); asmlinkage void xen_bounds(void); asmlinkage void xen_invalid_op(void); |