Just adding another me too (on Fedora 14). Temporarily turning off selinux and doing

LD_PRELOAD="/dev/shm/glibc-2.12.1-4/lib64/libc.so.6 /dev/shm/glibc-2.12.1-4/lib64/libpthread.so.0" chromium-browser --app=http://news.bbc.co.uk/1/hi/entertainment/8266142.stm

didn't produce the distorted sound (I used chromium so that the LD_PRELOAD environment variable would actually be passed to the flash plugin). Looking at the changelog for glibc-2.12.90-4 shows:

* Fri Jul 02 2010 Andreas Schwab <email address hidden> - 2.12.90-4
- Update from master
  - Work around kernel rejecting valid absolute timestamps
  - Improve 64bit memcpy/memmove for Atom, Core 2 and Core i7
  - Fix error handling in Linux getlogin*
- Workaround assembler bug sneaking in nopl (#579838)
- Fix scope handling during dl_close
- Fix setxid race handling exiting threads

It would be interesting to know if this is happening on AMD 64 bit machine. It is interesting that previous comments suggest the 32 bit flash does not seem to be demonstrating this problem.

I used chromium to run valgrind on the flash plugin ( chromium-browser --plugin-launcher="valgrind" --app=http://news.bbc.co.uk/1/hi/entertainment/8266142.stm --no-sandbox ). Large amounts of
"Conditional jump or move depends on uninitialised value(s)"
went past but just before it started outputting sound the following came up:

==2100== Conditional jump or move depends on uninitialised value(s)
==2100==    at 0x1B2E9361: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF89F92: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF8A784: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF8F8CA: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF916E0: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF5FF4A: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF61ABD: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF61AD2: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF18AC7: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF18BE4: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF80D43: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AE7126A: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==
==2100== Thread 9:
==2100== Source and destination overlap in memcpy(0x256d7170, 0x256d7570, 1280)
==2100==    at 0x4A06A3A: memcpy (mc_replace_strmem.c:497)
==2100==    by 0x1B122B87: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1B1230DF: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1B1232C5: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF491F0: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1AF4AFDA: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1B06DA69: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1B06EA23: ??? (in /usr/lib64/mozilla/plugins/libflashplayer.so)
==2100==    by 0x1EF26D88: write_data (flashsupport.c:872)
==2100==    by 0x1F14F505: ??? (in /usr/lib64/libpulse.so.0.12.2)
==2100==    by 0x1F390C02: ??? (in /usr/lib64/libpulsecommon-0.9.21.so)
==2100==    by 0x1F391358: pa_pdispatch_run (in /usr/lib64/libpulsecommon-0.9.21.so)
==2100==

While running under valgrind the distortion issue did not seem to occur (but sound was played back with big pauses every few seconds).

On a related note, is there a glibc environment flag that can be set to force a generic memcpy routine to run?