WSL2-Linux-Kernel/arch
Zhenzhong Duan b23e5844df xen/pv: Fix a boot up hang revealed by int3 self test
Commit 7457c0da02 ("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>
2019-07-17 08:09:59 +02:00
..
alpha Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
arc Kbuild updates for v5.3 2019-07-12 16:03:16 -07:00
arm Merge branch 'i2c/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-07-15 21:10:39 -07:00
arm64 pci-v5.3-changes 2019-07-15 20:44:49 -07:00
c6x Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2019-07-10 21:42:03 -07:00
csky Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
h8300 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2019-07-10 21:42:03 -07:00
hexagon Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-07-08 21:48:15 -07:00
ia64 TTY / Serial driver updates for 5.3-rc1 2019-07-11 15:38:21 -07:00
m68k Merge branch 'akpm' (patches from Andrew) 2019-07-12 11:40:28 -07:00
microblaze clone3-v5.3 2019-07-11 10:09:44 -07:00
mips asm-generic: remove ptrace.h 2019-07-12 15:41:33 -07:00
nds32 Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
nios2 nios2 update for v5.3-rc1 2019-07-12 15:38:05 -07:00
openrisc dma-mapping updates for Linux 5.3 2019-07-12 15:13:55 -07:00
parisc Kbuild updates for v5.3 2019-07-12 16:03:16 -07:00
powerpc HMM patches for 5.3 2019-07-14 19:42:11 -07:00
riscv Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
s390 Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
sh asm-generic: remove ptrace.h 2019-07-12 15:41:33 -07:00
sparc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2019-07-13 16:04:19 -07:00
um This pull request contains the following changes for UML: 2019-07-14 17:17:34 -07:00
unicore32 Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
x86 xen/pv: Fix a boot up hang revealed by int3 self test 2019-07-17 08:09:59 +02:00
xtensa dma-mapping updates for Linux 5.3 2019-07-12 15:13:55 -07:00
.gitignore
Kconfig