semantic: 0.195
device: 0.133
other: 0.089
graphic: 0.079
network: 0.078
socket: 0.066
files: 0.058
performance: 0.057
vnc: 0.049
permissions: 0.048
debug: 0.044
boot: 0.043
PID: 0.043
KVM: 0.018
debug: 0.297
PID: 0.143
files: 0.120
other: 0.102
performance: 0.069
device: 0.063
semantic: 0.059
KVM: 0.027
boot: 0.024
graphic: 0.023
network: 0.022
socket: 0.020
permissions: 0.018
vnc: 0.014

qemu-user doesn't block target signals on entry to signal hanlder.

Upon entry to a target signal handler the function process_pending_signals in linux-user/signal.c block the appropriate host signals, but signals already received and queued by Qemu are not blocked. If multiple signals arrive in quick succession this results incorrect recursion in the target signal handler.

The attached test case my be run as:

$ (sleep 2 ; echo) | qemu-i386 ./a.out
.................. Recursion in signal handler!
qemu: uncaught target signal 6 (Aborted) - core dumped



The patches to block signals on entry to the signal handler have now been applied to master.