force_sig_info can sleep under an -rt kernel, so attempting to send a
breakpoint SIGTRAP with interrupts disabled yields the following BUG:
BUG: sleeping function called from invalid context at
/kernel-source/kernel/locking/rtmutex.c:917
in_atomic(): 0, irqs_disabled(): 128, pid: 551, name: test.sh
CPU: 5 PID: 551 Comm: test.sh Not tainted 4.1.13-rt13 #7
Hardware name: Freescale Layerscape 2085a RDB Board (DT)
Call trace:
dump_backtrace+0x0/0x128
show_stack+0x24/0x30
dump_stack+0x80/0xa0
___might_sleep+0x128/0x1a0
rt_spin_lock+0x2c/0x40
force_sig_info+0xcc/0x210
brk_handler.part.2+0x6c/0x80
brk_handler+0xd8/0xe8
do_debug_exception+0x58/0xb8
This patch fixes the problem by ensuring that interrupts are enabled
prior to sending the SIGTRAP if they were already enabled in the user
context.
Reported-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
e04a28d45f