diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-03-03 18:13:24 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-03-03 18:13:24 -0500 |
| commit | cfbe87bd6f644e2b9b172516d94b971ed94dfc89 (patch) | |
| tree | 94d93af2a01a55a25cc2794c3b8da12e524a9a54 /src/backend/storage/ipc | |
| parent | 9050999efea72eb763fd9349d295761f4ff4da4d (diff) | |
Clean up assorted failures under clang's -fsanitize=undefined checks.
Most of these are cases where we could call memcpy() or other libc
functions with a NULL pointer and a zero count, which is forbidden
by POSIX even though every production version of libc allows it.
We've fixed such things before in a piecemeal way, but apparently
never made an effort to try to get them all. I don't claim that
this patch does so either, but it gets every failure I observe in
check-world, using clang 12.0.1 on current RHEL8.
numeric.c has a different issue that the sanitizer doesn't like:
"ln(-1.0)" will compute log10(0) and then try to assign the
resulting -Inf to an integer variable. We don't actually use the
result in such a case, so there's no live bug.
Back-patch to all supported branches, with the idea that we might
start running a buildfarm member that tests this case. This includes
back-patching c1132aae3 (Check the size in COPY_POINTER_FIELD),
which previously silenced some of these issues in copyfuncs.c.
Discussion: https://postgr.es/m/CALNJ-vT9r0DSsAOw9OXVJFxLENoVS_68kJ5x0p44atoYH+H4dg@mail.gmail.com
Diffstat (limited to 'src/backend/storage/ipc')
| -rw-r--r-- | src/backend/storage/ipc/shm_mq.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c index 5195e9e0ef5..405f7a1ef04 100644 --- a/src/backend/storage/ipc/shm_mq.c +++ b/src/backend/storage/ipc/shm_mq.c @@ -730,8 +730,11 @@ shm_mq_receive(shm_mq_handle *mqh, Size *nbytesp, void **datap, bool nowait) /* Copy as much as we can. */ Assert(mqh->mqh_partial_bytes + rb <= nbytes); - memcpy(&mqh->mqh_buffer[mqh->mqh_partial_bytes], rawdata, rb); - mqh->mqh_partial_bytes += rb; + if (rb > 0) + { + memcpy(&mqh->mqh_buffer[mqh->mqh_partial_bytes], rawdata, rb); + mqh->mqh_partial_bytes += rb; + } /* * Update count of bytes read, with alignment padding. Note that this |