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author | Mikulas Patocka <mpatocka@redhat.com> | 2023-09-16 15:49:42 +0200 |
---|---|---|
committer | Helge Deller <deller@gmx.de> | 2023-09-19 21:12:18 +0200 |
commit | 2529497cb6b298e732e8dbe5212da7925240b4f4 (patch) | |
tree | a8f9d2df6f2e950c466b93ff1eb8018f80e2b1b1 /linux-user/hppa | |
parent | cf6b28d41bc944c3b498489ee916a3d8c72ff6be (diff) | |
download | qemu-2529497cb6b298e732e8dbe5212da7925240b4f4.zip qemu-2529497cb6b298e732e8dbe5212da7925240b4f4.tar.gz qemu-2529497cb6b298e732e8dbe5212da7925240b4f4.tar.bz2 |
linux-user/hppa: clear the PSW 'N' bit when delivering signals
qemu-hppa may crash when delivering a signal. It can be demonstrated with
this program. Compile the program with "hppa-linux-gnu-gcc -O2 signal.c"
and run it with "qemu-hppa -one-insn-per-tb a.out". It reports that the
address of the flag is 0xb4 and it crashes when attempting to touch it.
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <signal.h>
sig_atomic_t flag;
void sig(int n)
{
printf("&flag: %p\n", &flag);
flag = 1;
}
int main(void)
{
struct sigaction sa;
struct itimerval it;
sa.sa_handler = sig;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (sigaction(SIGALRM, &sa, NULL)) perror("sigaction"), exit(1);
it.it_interval.tv_sec = 0;
it.it_interval.tv_usec = 100;
it.it_value.tv_sec = it.it_interval.tv_sec;
it.it_value.tv_usec = it.it_interval.tv_usec;
if (setitimer(ITIMER_REAL, &it, NULL)) perror("setitimer"), exit(1);
while (1) {
}
}
The reason for the crash is that the signal handling routine doesn't clear
the 'N' flag in the PSW. If the signal interrupts a thread when the 'N'
flag is set, the flag remains set at the beginning of the signal handler
and the first instruction of the signal handler is skipped.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: qemu-stable@nongnu.org
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'linux-user/hppa')
-rw-r--r-- | linux-user/hppa/signal.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/linux-user/hppa/signal.c b/linux-user/hppa/signal.c index f253a15..3a976ac 100644 --- a/linux-user/hppa/signal.c +++ b/linux-user/hppa/signal.c @@ -159,6 +159,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, } env->iaoq_f = haddr; env->iaoq_b = haddr + 4; + env->psw_n = 0; return; give_sigsegv: |