PID: 0.146
performance: 0.128
device: 0.104
semantic: 0.103
other: 0.093
files: 0.077
debug: 0.070
graphic: 0.060
permissions: 0.048
network: 0.046
socket: 0.042
vnc: 0.040
boot: 0.027
KVM: 0.016
debug: 0.849
performance: 0.033
PID: 0.021
files: 0.021
semantic: 0.017
other: 0.015
device: 0.009
KVM: 0.007
graphic: 0.006
network: 0.006
socket: 0.005
permissions: 0.004
boot: 0.004
vnc: 0.004

qemu crashes when doing iotest on  virtio-9p filesystem 

Qemu crashes when doing avocado-vt test on virtio-9p filesystem.
This bug can be reproduced running https://github.com/autotest/tp-qemu/blob/master/qemu/tests/9p.py.
The crash stack goes like:

Program terminated with signal SIGSEGV, Segmentation fault.
#0  v9fs_mark_fids_unreclaim (pdu=pdu@entry=0xaaab00046868, path=path@entry=0xffff851e2fa8)
    at hw/9pfs/9p.c:505
#1  0x0000aaaae3585acc in v9fs_unlinkat (opaque=0xaaab00046868) at hw/9pfs/9p.c:2590
#2  0x0000aaaae3811c10 in coroutine_trampoline (i0=<optimized out>, i1=<optimized out>)
    at util/coroutine-ucontext.c:116
#3  0x0000ffffa13ddb20 in ?? () from /lib64/libc.so.6
Backtrace stopped: not enough registers or memory available to unwind further

A segment fault is triggered at hw/9pfs/9p.c line 505

    for (fidp = s->fid_list; fidp; fidp = fidp->next) {
        if (fidp->path.size != path->size) {     # fidp is invalid 
            continue;
        }

(gdb) p path
$10 = (V9fsPath *) 0xffff851e2fa8
(gdb) p *path
$11 = {size = 21, data = 0xaaaafed6f420 "./9p_test/p2a1/d0/f1"}
(gdb) p *fidp
Cannot access memory at address 0x101010101010101
(gdb) p *pdu
$12 = {size = 19, tag = 54, id = 76 'L', cancelled = 0 '\000', complete = {entries = {
      sqh_first = 0x0, sqh_last = 0xaaab00046870}}, s = 0xaaab000454b8, next = {
    le_next = 0xaaab000467c0, le_prev = 0xaaab00046f88}, idx = 88}
(gdb) 

Address Sanitizer shows error and saying that there is a heap-use-after-free on *fidp*.


This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/181