AuxXxilium/linux_dsm_epyc7002
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827409b2f5
linux_dsm_epyc7002/arch
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Ingo Molnar 827409b2f5 x86/fpu/math-emu: Fix crash in fork() 
During later stages of math-emu bootup the following crash triggers:

	 math_emulate: 0060:c100d0a8
	 Kernel panic - not syncing: Math emulation needed in kernel
	 CPU: 0 PID: 1511 Comm: login Not tainted 4.2.0-rc7+ #1012
	 [...]
	 Call Trace:
	  [<c181d50d>] dump_stack+0x41/0x52
	  [<c181c918>] panic+0x77/0x189
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c164c2d7>] math_emulate+0xba7/0xbd0
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c1109c3c>] ? __alloc_pages_nodemask+0x12c/0x870
	  [<c136ac20>] ? proc_clear_tty+0x40/0x70
	  [<c136ac6e>] ? session_clear_tty+0x1e/0x30
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c1003575>] do_device_not_available+0x45/0x70
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c18258e6>] error_code+0x5a/0x60
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c100c205>] arch_dup_task_struct+0x25/0x30
	  [<c1048cea>] copy_process.part.51+0xea/0x1480
	  [<c115a8e5>] ? dput+0x175/0x200
	  [<c136af70>] ? no_tty+0x30/0x30
	  [<c1157242>] ? do_vfs_ioctl+0x322/0x540
	  [<c104a21a>] _do_fork+0xca/0x340
	  [<c1057b06>] ? SyS_rt_sigaction+0x66/0x90
	  [<c104a557>] SyS_clone+0x27/0x30
	  [<c1824a80>] sysenter_do_call+0x12/0x12

The reason is the incorrect assumption in fpu_copy(), that FNSAVE
can be executed from math-emu kernels as well.

Don't try to copy the registers, the soft state will be copied
by fork anyway, so the child task inherits the parent task's
soft math state.

With this fix applied math-emu kernels boot up fine on modern
hardware and the 'no387 nofxsr' boot options.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-22 10:23:03 +02:00
..
alpha mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
arc ARCv2: spinlock/rwlock/atomics: reduce 1 instruction in exponential backoff 2015-08-07 13:56:16 +05:30
arm ARM: SoC fixes 2015-08-16 15:44:33 -07:00
arm64 arm64: VDSO: fix coarse clock monotonicity regression 2015-08-10 15:37:45 +01:00
avr32 avr32: handle NULL as a valid clock object 2015-07-27 09:14:07 +02:00
blackfin mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
c6x mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
cris mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
frv mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
h8300 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
hexagon mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
ia64 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
m32r m32r: Add ioreadXX/iowriteXX big-endian mmio accessors 2015-07-23 18:08:28 -07:00
m68k mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
metag mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
microblaze mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
mips MIPS: Fix seccomp syscall argument for MIPS64 2015-08-16 15:00:59 +02:00
mn10300 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
nios2 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
openrisc mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
parisc parisc: mm: Fix a memory leak related to pmd not attached to the pgd 2015-07-19 08:56:14 +02:00
powerpc signal: fix information leak in copy_siginfo_from_user32 2015-08-07 04:39:40 +03:00
s390 Just two very small & simple patches. 2015-08-05 18:50:38 +03:00
score mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
sh mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
sparc sparc64: Fix userspace FPU register corruptions. 2015-08-06 19:13:25 -07:00
tile signal: fix information leak in copy_siginfo_from_user32 2015-08-07 04:39:40 +03:00
um mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
unicore32 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
x86 x86/fpu/math-emu: Fix crash in fork() 2015-08-22 10:23:03 +02:00
xtensa mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
.gitignore
Kconfig x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86 2015-07-18 03:42:51 +02:00