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Wanpeng Li 2fa5f04f85 x86/entry/64: Fix context tracking state warning when load_gs_index fails 
This warning:

 WARNING: CPU: 0 PID: 3331 at arch/x86/entry/common.c:45 enter_from_user_mode+0x32/0x50
 CPU: 0 PID: 3331 Comm: ldt_gdt_64 Not tainted 4.8.0-rc7+ #13
 Call Trace:
  dump_stack+0x99/0xd0
  __warn+0xd1/0xf0
  warn_slowpath_null+0x1d/0x20
  enter_from_user_mode+0x32/0x50
  error_entry+0x6d/0xc0
  ? general_protection+0x12/0x30
  ? native_load_gs_index+0xd/0x20
  ? do_set_thread_area+0x19c/0x1f0
  SyS_set_thread_area+0x24/0x30
  do_int80_syscall_32+0x7c/0x220
  entry_INT80_compat+0x38/0x50

... can be reproduced by running the GS testcase of the ldt_gdt test unit in
the x86 selftests.

do_int80_syscall_32() will call enter_form_user_mode() to convert context
tracking state from user state to kernel state. The load_gs_index() call
can fail with user gsbase, gsbase will be fixed up and proceed if this
happen.

However, enter_from_user_mode() will be called again in the fixed up path
though it is context tracking kernel state currently.

This patch fixes it by just fixing up gsbase and telling lockdep that IRQs
are off once load_gs_index() failed with user gsbase.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1475197266-3440-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 		2016-09-30 13:53:12 +02:00
..
boot x86/efi: Use efi_exit_boot_services() 2016-09-05 12:40:16 +01:00
configs kconfig: tinyconfig: provide whole choice blocks to avoid warnings 2016-09-01 17:52:01 -07:00
crypto crypto: sha512-mb - fix ctx pointer 2016-08-16 17:09:43 +08:00
entry x86/entry/64: Fix context tracking state warning when load_gs_index fails 2016-09-30 13:53:12 +02:00
events perf/x86/intel/bts: Make it an exclusive PMU 2016-09-22 14:56:08 +02:00
ia32 mm: remove more IS_ERR_VALUE abuses 2016-05-27 15:57:31 -07:00
include x86/init: Fix cr4_init_shadow() on CR4-less machines 2016-09-29 19:08:30 +02:00
kernel x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID 2016-09-30 13:53:04 +02:00
kvm Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-09-18 11:50:48 -07:00
lguest lguest: Read offset of device_cap later 2016-06-10 11:39:09 +02:00
lib x86/mm/kaslr: Fix -Wformat-security warning 2016-08-11 10:58:12 +02:00
math-emu
…
mm x86/mm/pat: Prevent hang during boot when mapping pages 2016-09-20 14:53:00 +01:00
net bpf, x86: add support for constant blinding 2016-05-16 13:49:32 -04:00
oprofile x86/cpufeature: Replace cpu_has_apic with boot_cpu_has() usage 2016-04-13 11:37:41 +02:00
pci PCI: Mark Haswell Power Control Unit as having non-compliant BARs 2016-09-01 08:52:29 -05:00
platform x86/efi: Only map RAM into EFI page tables if in mixed-mode 2016-09-20 14:53:04 +01:00
power x86/power/64: Use __pa() for physical address computation 2016-08-16 00:39:37 +02:00
purgatory Add sancov plugin 2016-06-07 22:57:10 +02:00
ras x86/RAS/AMD: Reduce the number of IPIs when prepping error injection 2016-07-08 11:29:26 +02:00
realmode x86/boot: Rework reserve_real_mode() to allow multiple tries 2016-08-11 11:15:01 +02:00
tools x86/insn: Add AVX-512 support to the instruction decoder 2016-07-21 09:37:11 -03:00
um um/ptrace: Fix the syscall number update after a ptrace 2016-09-07 09:25:04 -07:00
video x86/video: Don't assume all FB devices are PCI devices 2016-03-15 11:08:26 +01:00
xen xen: change the type of xen_vcpu_id to uint32_t 2016-08-24 18:17:27 +01:00
.gitignore
…
Kbuild perf/x86: Move perf_event.c ............... => x86/events/core.c 2016-02-09 10:23:49 +01:00
Kconfig mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS 2016-08-30 10:10:21 -07:00
Kconfig.cpu
…
Kconfig.debug Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 09:32:27 -07:00
Makefile kbuild: abort build on bad stack protector flag 2016-07-26 16:19:19 -07:00
Makefile.um
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Makefile_32.cpu
…