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sparc64: Do not define thread fpregs save area as zero-length array. 

This breaks the stack end corruption detection facility.

What that facility does it write a magic value to "end_of_stack()"
and checking to see if it gets overwritten.

"end_of_stack()" is "task_thread_info(p) + 1", which for sparc64 is
the beginning of the FPU register save area.

So once the user uses the FPU, the magic value is overwritten and the
debug checks trigger.

Fix this by making the size explicit.

Due to the size we use for the fpsaved[], gsr[], and xfsr[] arrays we
are limited to 7 levels of FPU state saves.  So each FPU register set
is 256 bytes, allocate 256 * 7 for the fpregs area.

Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2014-10-18 23:12:33 -04:00
parent 84bd6d8b9c
commit e2653143d7
1 changed files with 2 additions and 1 deletions
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3
arch/sparc/include/asm/thread_info_64.h
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@ -63,7 +63,8 @@ struct thread_info {
struct pt_regs *kern_una_regs;
unsigned int kern_una_insn;
unsigned long fpregs[0] __attribute__ ((aligned(64)));
unsigned long fpregs[(7 * 256) / sizeof(unsigned long)]
__attribute__ ((aligned(64)));
};
#endif /* !(__ASSEMBLY__) */