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cli: fixed wrong initialization in MT mode 

It's not good to mix old and new API
ZSTD_resetCStream() doesn't just set pledgedSrcSize :
it also sets the CCtx for a single thread compression.

Problem is, when 2+ threads are defined in cctx->requestedParams,
ZSTD_compress_generic() will want to start MT compression,
since initialization is supposed to have already happened (thanks to ZSTD_resetCStream())
except that the underlying ZSTDMT_CCtx* object is not created,
resulting in a segfault.

This is an invalid construction
(correct one is to use ZSTD_CCtx_setPledgedSrcSize()).
I haven't found a nice way to mitigate this impact if someone makes the same mistake.

At some point, removing the old API to keep only the new API within fileio.c will limit these risks.
dev
Yann Collet 2017-09-29 22:14:37 -07:00
parent fbd5ab7027
commit 8afb151c9b
2 changed files with 5 additions and 2 deletions
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3
lib/compress/zstd_compress.c
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@ -2756,6 +2756,7 @@ size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
ZSTD_inBuffer* input,
ZSTD_EndDirective endOp)
{
DEBUGLOG(5, "ZSTD_compress_generic");
/* check conditions */
if (output->pos > output->size) return ERROR(GENERIC);
if (input->pos > input->size) return ERROR(GENERIC);
@ -2798,7 +2799,7 @@ size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
#ifdef ZSTD_MULTITHREAD
if (cctx->appliedParams.nbThreads > 1) {
size_t const flushMin = ZSTDMT_compressStream_generic(cctx->mtctx, output, input, endOp);
DEBUGLOG(5, "ZSTDMT_compressStream_generic : %u", (U32)flushMin);
DEBUGLOG(5, "ZSTDMT_compressStream_generic result : %u", (U32)flushMin);
if ( ZSTD_isError(flushMin)
|| (endOp == ZSTD_e_end && flushMin == 0) ) { /* compression completed */
ZSTD_startNewCompression(cctx);

4
programs/fileio.c
View File

@ -446,6 +446,7 @@ static cRess_t FIO_createCResources(const char* dictFileName, int cLevel,
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_targetLength, comprParams->targetLength) );
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_compressionStrategy, (U32)comprParams->strategy) );
/* multi-threading */
DISPLAYLEVEL(5,"set nb threads = %u \n", g_nbThreads);
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_nbThreads, g_nbThreads) );
/* dictionary */
CHECK( ZSTD_CCtx_loadDictionary(ress.cctx, dictBuffer, dictBuffSize) );
@ -797,7 +798,8 @@ static int FIO_compressFilename_internal(cRess_t ress,
/* init */
#ifdef ZSTD_NEWAPI
CHECK( ZSTD_resetCStream(ress.cctx, fileSize) ); /* to pass fileSize */
if (fileSize!=0) /* if stdin, fileSize==0, but is effectively unknown */
ZSTD_CCtx_setPledgedSrcSize(ress.cctx, fileSize);
#elif defined(ZSTD_MULTITHREAD)
CHECK( ZSTDMT_resetCStream(ress.cctx, fileSize) );
#else