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author | Emilio G. Cota <cota@braap.org> | 2016-07-22 12:36:30 -0400 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-08-02 12:03:58 +0200 |
commit | 7266ae91a111001abda65c79299c9b7e365456b6 (patch) | |
tree | 9bbd8547070f5f5429a081f539ea85ddb5dcb38b /tests | |
parent | 767db021bc45affa7a7c20ea21730d2867a0c37f (diff) | |
download | qemu-7266ae91a111001abda65c79299c9b7e365456b6.zip qemu-7266ae91a111001abda65c79299c9b7e365456b6.tar.gz qemu-7266ae91a111001abda65c79299c9b7e365456b6.tar.bz2 |
qht: do not segfault when gathering stats from an uninitialized qht
So far, QHT functions assume that the passed qht has previously been
initialized--otherwise they segfault.
This patch makes an exception for qht_statistics_init, with the goal
of simplifying calling code. For instance, qht_statistics_init is
called from the 'info jit' dump, and given that under KVM the TB qht
is never initialized, we get a segfault. Thus, instead of complicating
the 'info jit' code with additional checks, let's allow passing an
uninitialized qht to qht_statistics_init.
While at it, add a test for this to test-qht.
Before the patch (for $ qemu -enable-kvm [...]):
(qemu) info jit
[...]
direct jump count 0 (0%) (2 jumps=0 0%)
Program received signal SIGSEGV, Segmentation fault.
After the patch the "TB hash buckets", "TB hash occupancy"
and "TB hash avg chain" lines are omitted.
(qemu) info jit
[...]
direct jump count 0 (0%) (2 jumps=0 0%)
TB hash buckets 0/0 (-nan% head buckets used)
TB hash occupancy nan% avg chain occ. Histogram: (null)
TB hash avg chain nan buckets. Histogram: (null)
[...]
Reported by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1469205390-14369-1-git-send-email-cota@braap.org>
[Extract printing statistics to an entirely separate function. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'tests')
-rw-r--r-- | tests/test-qht.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tests/test-qht.c b/tests/test-qht.c index f1d6283..46a64b6 100644 --- a/tests/test-qht.c +++ b/tests/test-qht.c @@ -95,8 +95,12 @@ static void iter_check(unsigned int count) static void qht_do_test(unsigned int mode, size_t init_entries) { + /* under KVM we might fetch stats from an uninitialized qht */ + check_n(0); + qht_init(&ht, 0, mode); + check_n(0); insert(0, N); check(0, N, true); check_n(N); |