Date: Fri, 20 Mar 2015 15:59:52 +0200 From: "Ivan A. Kosarev" <ivan@ivan-labs.com> To: freebsd-current@freebsd.org Cc: Ed Maste <emaste@freebsd.org> Subject: Use of chunksize before initialization Message-ID: <550C27D8.2010105@ivan-labs.com>
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Hello everybody,
The malloc_init_hard() function defined in jemalloc_jemalloc.c, FreeBSD
11 r277486 reads:
static bool
malloc_init_hard(void)
{
...
if (base_boot()) {
malloc_mutex_unlock(&init_lock);
eturn (true);
}
if (chunk_boot()) {
malloc_mutex_unlock(&init_lock);
return (true);
}
...
The second call initializes the 'chunksize' global variable defined in
jemalloc_chunk.c:
bool
chunk_boot(void)
{
/* Set variables according to the value of opt_lg_chunk. */
chunksize = (ZU(1) << opt_lg_chunk);
assert(chunksize >= PAGE);
...
However, it seems the first call to base_boot() depends on that variable
already:
(gdb) bt
#0 thr_kill () at thr_kill.S:3
#1 0x0000000801241408 in __raise (s=6) at /usr/src/lib/libc/gen/raise.c:51
#2 0x000000000041d817 in __interceptor_raise () at
/usr/home/ik/llvm/llvm.current/projects/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc:2097
#3 0x000000080123f969 in abort () at /usr/src/lib/libc/stdlib/abort.c:65
#4 0x000000000041c5d9 in __interceptor_abort () at
/usr/home/ik/llvm/llvm.current/projects/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc:1851
#5 0x00000008011a8d64 in __je_chunk_alloc (size=<optimized out>,
alignment=<optimized out>, base=<optimized out>, zero=<optimized out>,
dss_prec=dss_prec_disabled) at jemalloc_chunk.c:150
#6 0x00000008011a9bfc in base_pages_alloc (minsize=128) at
jemalloc_base.c:35
#7 __je_base_alloc (size=<optimized out>) at jemalloc_base.c:57
#8 0x00000008011a9c96 in __je_base_calloc (number=<optimized out>,
size=6) at jemalloc_base.c:74
#9 0x00000008008ae548 in mutex_init (calloc_cb=0x0, mutex=<optimized
out>, mutex_attr=<optimized out>) at
/usr/src/lib/libthr/thread/thr_mutex.c:145
#10 _pthread_mutex_init_calloc_cb (mutex=0x801487c90, calloc_cb=0x0) at
/usr/src/lib/libthr/thread/thr_mutex.c:229
#11 0x00000008011a18da in __je_malloc_mutex_init (mutex=0x18744) at
jemalloc_mutex.c:97
#12 0x00000008011b428d in malloc_init_hard () at jemalloc_jemalloc.c:698
#13 malloc_init () at jemalloc_jemalloc.c:296
#14 0x0000000801243ea2 in ?? () from /lib/libc.so.7
#15 0x00000008006a5400 in ?? ()
#16 0x000000080089e5b0 in ?? () from /libexec/ld-elf.so.1
#17 0x00007fffffffe0b0 in ?? ()
#18 0x0000000801139d06 in _init () from /lib/libc.so.7
#19 0x00007fffffffe0b0 in ?? ()
Note that base_pages() calls chunk_alloc() with chucksize used as the
alignment value:
static bool
base_pages_alloc(size_t minsize)
{
...
base_pages = chunk_alloc(csize, chunksize, true, &zero,
chunk_dss_prec_get());
...
and the latter tests it against zero:
void *
chunk_alloc(size_t size, size_t alignment, bool base, bool *zero,
dss_prec_t dss_prec)
{
...
assert(alignment != 0);
....
so we sometimes we end up with:
<jemalloc>: jemalloc_chunk.c:152: Failed assertion: "alignment != 0"
Here's more of failures of this kind around:
http://lab.llvm.org:8011/builders/sanitizer_x86_64-freebsd/builds/4758/steps/make-check-tsan/logs/stdio
Can you please let me know if the analysis is correct and there's
something to fix about initialization of the variable?
Thanks.
--
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