add new classifier result

1 files changed, 76 insertions, 0 deletions

diff --git a/results/classifier/105/semantic/1299190 b/results/classifier/105/semantic/1299190
new file mode 100644
index 00000000..b79560b1
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+++ b/results/classifier/105/semantic/1299190
@@ -0,0 +1,76 @@
+semantic: 0.700
+other: 0.582
+mistranslation: 0.574
+instruction: 0.522
+device: 0.396
+graphic: 0.335
+network: 0.333
+boot: 0.296
+vnc: 0.276
+socket: 0.269
+assembly: 0.224
+KVM: 0.173
+
+Access to /proc/self/exe in linux-user mode
+
+This is based on a recent bug in GCC Bugzilla: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60681
+
+It looks like libbacktrace (GCC runtime library used for obtaining stack traces) uses /proc/self/exe for error reporting. Currently this is mapped to qemu-arm which effectively disables libbacktrace on linux-user.
+
+It seems that QEMU already supports /proc/self/{maps,stat,auxv} so addition of /proc/self/exe may be trivial.
+
+This tiny patch seems to work.
+
+I think the problem is not in libbacktrace per se but rather libsanitizer initializing libbacktrace with contents of /proc/self/exe. Patch is still relevant though.
+
+Looks good, I'll get this to linux-user que once QEMU 2.0 is released.
+
+That patch will copy the whole of the target executable into a temporary file without changing any of it -- the fake_open mechanism is really intended for cases where we need to return modified results. Wouldn't it be easier to just have something in do_open() that said:
+    if (is_proc_myself(pathname, "exe")) {
+        return get_errno(open(exec_path), flags, mode);
+    }
+
+That will then give the right behaviour for read-only executables and other error-related corner cases.
+
+(See also the logic in the readlink/readlinkat handling which already specialcases /proc/self/exe using exec_path.)
+
+
+(I got the bracket placement wrong there so as you can tell the code is untested :-))
+
+
+Yes, it works. Here is updated patch.
+
+Some nits:
+ The "(CPUArchState *)" cast isn't necessary
+ We should use exec_path, not ts->bprm->argv[0] (the guest argv[0] isn't necessarily the executable path)
+ We don't want to call path() here -- exec_path is a host path, and only guest filename paths need to go through path().
+
+Looking a little more closely at the logic in main.c I wonder if we actually want:
+
+   if (is_proc_myself(pathname, "exe")) {
+        execfd = qemu_getauxval(AT_EXECFD);
+        if (execfd) {
+             return execfd;
+        }
+        return get_errno(open(exec_path, flags, mode));
+    }
+
+Also if you'd like us to apply your patches we'll need at least a "Signed-off-by: " line from you.
+
+
+Ok, fixed.
+
+Thanks. That version
+Reviewed-by: Peter Maydell <email address hidden>
+
+
+Hi,
+
+Is this patch deployed in new version of QEMU?
+
+Thanks,
+Maxim
+
+This bug was fixed by commit aa07f5ecf9828 in 2014 and has been released in QEMU.
+
+