| Description: | In the Linux kernel, the following vulnerability has been resolved:
s390/ptrace: handle setting of fpc register correctly If the content
of the floating point control (fpc) register of a traced process is
modified with the ptrace interface the new value is tested for
validity by temporarily loading it into the fpc register. This may
lead to corruption of the fpc register of the tracing process: if an
interrupt happens while the value is temporarily loaded into the fpc
register, and within interrupt context floating point or vector
registers are used, the current fp/vx registers are saved with
save_fpu_regs() assuming they belong to user space and will be loaded
into fp/vx registers when returning to user space. test_fp_ctl()
restores the original user space fpc register value, however it will
be discarded, when returning to user space. In result the tracer will
incorrectly continue to run with the value that was supposed to be
used for the traced process. Fix this by saving fpu register contents
with save_fpu_regs() before using test_fp_ctl().
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