when you debugging qemu, it will keep firing SIGUSR1 so gdb will always catched in some breakpooints that are not defined by you, to turn off the SIGUSR1, you have to:

(gdb) info signal SIGUSR1

Signal        Stop      Print   Pass to program Description
SIGUSR1       Yes       Yes     Yes             User defined signal 1

And if deemed to not be of interest, where you just want your program to continue without prompting or spamming, something like the following does the trick:

(gdb) handle SIGUSR1 noprint nostop

Signal        Stop      Print   Pass to program Description
SIGUSR1       No        No      Yes             User defined signal 1