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Re: SIGBUS failure for misc/tst-bz21269 on i386
On 03/27/2018 11:47 PM, Aurelien Jarno wrote:
Here is the coredump that I can get:
Thread 1 "tst-bz21269" received signal SIGBUS, Bus error.
0x565564a0 in do_test () at ../sysdeps/unix/sysv/linux/i386/tst-bz21269.c:217
217 while (atomic_load (&ftx) != 0)
(gdb) bt
#0 0x565564a0 in do_test () at ../sysdeps/unix/sysv/linux/i386/tst-bz21269.c:217
#1 0x56556bc2 in support_test_main (argc=<optimized out>, argv=0xffffd518, config=0xffffd424) at support_test_main.c:321
#2 0x56556061 in main (argc=2, argv=0xffffd514) at ../support/test-driver.c:164
(gdb) print &ftx
$1 = (atomic_uint *) 0x5655a0e0 <ftx>
(gdb) print ftx
$2 = 0
Ahh. I see.
/* Fire up thread modify_ldt call. */
atomic_store (&ftx, 2);
while (atomic_load (&ftx) != 0)
;
/* On success, modify_ldt will segfault us synchronously and we
will escape via siglongjmp. */
support_record_failure ();
But:
xsethandler (SIGSEGV, sigsegv_handler, 0);
/* 32-bit kernels send SIGILL instead of SIGSEGV on IRET faults. */
xsethandler (SIGILL, sigsegv_handler, 0);
So some kernels apparently use SIGBUS instead, and the crash actually
shows the test succeeded.
Would you please try the attached patch?
Thanks,
Florian
Subject: [PATCH] Linux i386: tst-bz21269 triggers SIGBUS on some kernels
To: libc-alpha@sourceware.org
In addition to SIGSEGV and SIGILL, SIGBUS is also a possible signal
generated by the kernel.
2018-03-28 Florian Weimer <fweimer@redhat.com>
* sysdeps/unix/sysv/linux/i386/tst-bz21269.c (do_test): Also
capture SIGBUS.
diff --git a/sysdeps/unix/sysv/linux/i386/tst-bz21269.c b/sysdeps/unix/sysv/linux/i386/tst-bz21269.c
index 353e36507d..6ee3fc62be 100644
--- a/sysdeps/unix/sysv/linux/i386/tst-bz21269.c
+++ b/sysdeps/unix/sysv/linux/i386/tst-bz21269.c
@@ -177,6 +177,8 @@ do_test (void)
xsethandler (SIGSEGV, sigsegv_handler, 0);
/* 32-bit kernels send SIGILL instead of SIGSEGV on IRET faults. */
xsethandler (SIGILL, sigsegv_handler, 0);
+ /* Some kernels send SIGBUS instead. */
+ xsethandler (SIGBUS, sigsegv_handler, 0);
thread = xpthread_create (0, threadproc, 0);