signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL)

stable inclusion
from stable-5.10.80
commit a4cbf00e5ab8022f45ffc93c10feced1b2334892
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a4cbf00e5ab8022f45ffc93c10feced1b2334892

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[ Upstream commit ce0ee4e6 ]

Today the sh code allocates memory the first time a process uses
the fpu.  If that memory allocation fails, kill the affected task
with force_sig(SIGKILL) rather than do_group_exit(SIGKILL).

Calling do_group_exit from an exception handler can potentially lead
to dead locks as do_group_exit is not designed to be called from
interrupt context.  Instead use force_sig(SIGKILL) to kill the
userspace process.  Sending signals in general and force_sig in
particular has been tested from interrupt context so there should be
no problems.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Fixes: 0ea820cf ("sh: Move over to dynamically allocated FPU context.")
Link: https://lkml.kernel.org/r/20211020174406.17889-6-ebiederm@xmission.com


Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>