On Wed, 20 Mar 2024 00:24:37 +0300, "Vladimir Sementsov-Ogievskiy" <vsement...@yandex-team.ru> wrote: > Hi all! > > From fuzzing I've got a fuzz-data, which produces the following crash: > > qemu-fuzz-x86_64: ../hw/net/virtio-net.c:134: void > flush_or_purge_queued_packets(NetClientState *): Assertion > `!virtio_net_get_subqueue(nc)->async_tx.elem' failed. > ==2172308== ERROR: libFuzzer: deadly signal > #0 0x5bd8c748b5a1 in __sanitizer_print_stack_trace > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x26f05a1) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #1 0x5bd8c73fde38 in fuzzer::PrintStackTrace() > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x2662e38) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #2 0x5bd8c73e38b3 in fuzzer::Fuzzer::CrashCallback() > (/home/settlements/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x26488b3) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #3 0x739eec84251f (/lib/x86_64-linux-gnu/libc.so.6+0x4251f) (BuildId: > c289da5071a3399de893d2af81d6a30c62646e1e) > #4 0x739eec8969fb in __pthread_kill_implementation > nptl/./nptl/pthread_kill.c:43:17 > #5 0x739eec8969fb in __pthread_kill_internal > nptl/./nptl/pthread_kill.c:78:10 > #6 0x739eec8969fb in pthread_kill nptl/./nptl/pthread_kill.c:89:10 > #7 0x739eec842475 in gsignal signal/../sysdeps/posix/raise.c:26:13 > #8 0x739eec8287f2 in abort stdlib/./stdlib/abort.c:79:7 > #9 0x739eec82871a in __assert_fail_base assert/./assert/assert.c:92:3 > #10 0x739eec839e95 in __assert_fail assert/./assert/assert.c:101:3 > #11 0x5bd8c995d9e2 in flush_or_purge_queued_packets > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../hw/net/virtio-net.c:134:5 > #12 0x5bd8c9918a5f in virtio_net_queue_reset > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../hw/net/virtio-net.c:563:5 > #13 0x5bd8c9b724e5 in virtio_queue_reset > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../hw/virtio/virtio.c:2492:9 > #14 0x5bd8c8bcfb7c in virtio_pci_common_write > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../hw/virtio/virtio-pci.c:1372:13 > #15 0x5bd8c9e19cf3 in memory_region_write_accessor > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../softmmu/memory.c:492:5 > #16 0x5bd8c9e19631 in access_with_adjusted_size > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../softmmu/memory.c:554:18 > #17 0x5bd8c9e17f3c in memory_region_dispatch_write > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../softmmu/memory.c:1514:16 > #18 0x5bd8c9ea3bbe in flatview_write_continue > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../softmmu/physmem.c:2825:23 > #19 0x5bd8c9e91aab in flatview_write > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../softmmu/physmem.c:2867:12 > #20 0x5bd8c9e91568 in address_space_write > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../softmmu/physmem.c:2963:18 > #21 0x5bd8c74c8a90 in __wrap_qtest_writeq > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../tests/qtest/fuzz/qtest_wrappers.c:187:9 > #22 0x5bd8c74dc4da in op_write > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../tests/qtest/fuzz/generic_fuzz.c:487:13 > #23 0x5bd8c74d942e in generic_fuzz > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../tests/qtest/fuzz/generic_fuzz.c:714:17 > #24 0x5bd8c74c016e in LLVMFuzzerTestOneInput > /home/vsementsov/work/src/qemu/yc7-fuzz/build/../tests/qtest/fuzz/fuzz.c:152:5 > #25 0x5bd8c73e4e43 in fuzzer::Fuzzer::ExecuteCallback(unsigned char > const*, unsigned long) > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x2649e43) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #26 0x5bd8c73cebbf in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, > unsigned long) > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x2633bbf) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #27 0x5bd8c73d4916 in fuzzer::FuzzerDriver(int*, char***, int > (*)(unsigned char const*, unsigned long)) > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x2639916) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #28 0x5bd8c73fe732 in main > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x2663732) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > #29 0x739eec829d8f in __libc_start_call_main > csu/../sysdeps/nptl/libc_start_call_main.h:58:16 > #30 0x739eec829e3f in __libc_start_main csu/../csu/libc-start.c:392:3 > #31 0x5bd8c73c9484 in _start > (/home/vsementsov/work/src/qemu/yc7-fuzz/build/qemu-fuzz-x86_64+0x262e484) > (BuildId: b41827f440fd9feaa98c667dbdcc961abb2799ae) > > > > How to reproduce: > ./configure --target-list=x86_64-softmmu --enable-debug --disable-docs > --cc=clang --cxx=clang++ --enable-fuzzing --enable-sanitizers --enable-slirp > make -j20 qemu-fuzz-x86_64 > ./build/qemu-fuzz-x86_64 --fuzz-target=generic-fuzz-virtio-net-pci-slirp > ../generic-fuzz-virtio-net-pci-slirp.crash-7707e14adea64d129be88faeb6ca57dab6118ec5 > > > This ...crash-7707... file is attached. > > git-bisect points to 7dc6be52f4ead25e7da8fb758900bdcb527996f7 "virtio-net: > support queue reset" as a first bad commit. That's a commit which introduces > virtio_net_queue_reset() function. > > > I'm a newbie in qemu-fuzzing, and don't know virtio-net code, so I've no idea > how to debug this thing further. I even don't know, how to get a normal > coredump file to open it in gdb, it's not produced from fuzzing process... > > > I tried to search for "async_tx.elem" in git log, and found two commits, > fixing similar crashes: > > bc5add1dadcc140fef9af4fe215167e796cd1a58 "vhost-vdpa: fix assert > !virtio_net_get_subqueue(nc)->async_tx.elem in virtio_net_reset"
This fixed that by updating the vdpa "receive" callback. You use the slirp, so should we fix that by updating the "receive" callback of slirp? Thanks. > > and > > 5fe19fb81839ea42b592b409f725349cf3c73551 "net: use peer when purging queue > in qemu_flush_or_purge_queue_packets()" > > but I failed to get helping idea from them. > > > > Could someone please help with this? > > > -- > Best regards, > Vladimir
