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"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
generic-fuzz-virtio-net-pci-slirp.crash-7707e14adea64d129be88faeb6ca57dab6118ec5
Description: Binary data