diff options
Diffstat (limited to 'results/classifier/accel-gemma3:12b/kvm/2143')
| -rw-r--r-- | results/classifier/accel-gemma3:12b/kvm/2143 | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/results/classifier/accel-gemma3:12b/kvm/2143 b/results/classifier/accel-gemma3:12b/kvm/2143 new file mode 100644 index 00000000..f33a46a2 --- /dev/null +++ b/results/classifier/accel-gemma3:12b/kvm/2143 @@ -0,0 +1,39 @@ + +ladr_match can cause bus error due to unaligned fetch +Description of problem: +On a SPARC host system, which does not support unaligned fetches, QEMU sometimes takes a bus error in ladr_match. +Steps to reproduce: +1. (see QEMU command line above) +2. let the system boot +3. +Additional information: +Problem is a hack in ladr_match - hw/net/pcnet.c:635 (present since 2006!): + +``` +Core was generated by `./qemu-system-sparc -rtc base=utc,clock=host -vga cg3 -g 1024x768x8 -machine SS'. +Program terminated with signal SIGKILL, Killed. +#0 0xffffffff7ec3b178 in ladr_match (size=110, buf=0xffffffff7ffee972 "33", s=0x808f2a20) at ../hw/net/pcnet.c:634 +634 if ((*(hdr->ether_dhost)&0x01) && +[Current thread is 632 (LWP 1 )] +(gdb) list +629 } +630 +631 static inline int ladr_match(PCNetState *s, const uint8_t *buf, int size) +632 { +633 struct qemu_ether_header *hdr = (void *)buf; +634 if ((*(hdr->ether_dhost)&0x01) && +635 ((uint64_t *)&s->csr[8])[0] != 0LL) { +636 uint8_t ladr[8] = { +637 s->csr[8] & 0xff, s->csr[8] >> 8, +638 s->csr[9] & 0xff, s->csr[9] >> 8, +(gdb) print &s->csr[8] +$1 = (uint16_t *) 0x808f4a7c +``` +The address of s->csr[8], in this case, is on a 4-byte boundary not an 8-byte boundary, so the hack to test for 8 bytes (4 x 16-bit words) being 0 by casting the address up to a pointer to uint64_t and dereferencing it fails. + +The data does not seem to be allocated with a deterministic alignment, this failure does not always occur. + +A solution to avoid alignment errors could be to test +``` + (s->csr[8] | s->csr[9] | s->csr[10] | s->csr[11]) != 0 +``` |