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Overview
| Comment: | Add compiler hints to disable TSAN for the routines that access the -shm file header in WAL mode using a double-read with memory barrier. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
3117c1b5a9e348fd8d16ba9d03fdafaa |
| User & Date: | drh 2020-05-19 15:51:10.216 |
Context
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2020-05-20
| ||
| 15:02 | Back out the change from [7fab1393c2b22b1f] that tries to convert invalid surrogate characters in UTF16 into the replacement character 0xfffd, as we find that this breaks some software. (check-in: 4218c7b71f user: drh tags: trunk) | |
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2020-05-19
| ||
| 15:51 | Add compiler hints to disable TSAN for the routines that access the -shm file header in WAL mode using a double-read with memory barrier. (check-in: 3117c1b5a9 user: drh tags: trunk) | |
| 15:40 | In os_win.c, avoid calling sqlite3_uri_boolean() on anything other than a main-db filename. (check-in: cb0a18e64f user: dan tags: trunk) | |
Changes
Changes to src/wal.c.
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*/
static void walShmBarrier(Wal *pWal){
if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
sqlite3OsShmBarrier(pWal->pDbFd);
}
}
/*
** Write the header information in pWal->hdr into the wal-index.
**
** The checksum on pWal->hdr is updated before it is written.
*/
| > > > > > > > > > > > > > | | 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 |
*/
static void walShmBarrier(Wal *pWal){
if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
sqlite3OsShmBarrier(pWal->pDbFd);
}
}
/*
** Add the SQLITE_NO_TSAN as part of the return-type of a function
** definition as a hint that the function contains constructs that
** might give false-positive TSAN warnings.
**
** See tag-20200519-1.
*/
#if defined(__clang__) && !defined(SQLITE_NO_TSAN)
# define SQLITE_NO_TSAN __attribute__((no_sanitize_thread))
#else
# define SQLITE_NO_TSAN
#endif
/*
** Write the header information in pWal->hdr into the wal-index.
**
** The checksum on pWal->hdr is updated before it is written.
*/
static SQLITE_NO_TSAN void walIndexWriteHdr(Wal *pWal){
volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
const int nCksum = offsetof(WalIndexHdr, aCksum);
assert( pWal->writeLock );
pWal->hdr.isInit = 1;
pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
|
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2137 2138 2139 2140 2141 2142 2143 | ** If and only if the read is consistent and the header is different from ** pWal->hdr, then pWal->hdr is updated to the content of the new header ** and *pChanged is set to 1. ** ** If the checksum cannot be verified return non-zero. If the header ** is read successfully and the checksum verified, return zero. */ | | | 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 |
** If and only if the read is consistent and the header is different from
** pWal->hdr, then pWal->hdr is updated to the content of the new header
** and *pChanged is set to 1.
**
** If the checksum cannot be verified return non-zero. If the header
** is read successfully and the checksum verified, return zero.
*/
static SQLITE_NO_TSAN int walIndexTryHdr(Wal *pWal, int *pChanged){
u32 aCksum[2]; /* Checksum on the header content */
WalIndexHdr h1, h2; /* Two copies of the header content */
WalIndexHdr volatile *aHdr; /* Header in shared memory */
/* The first page of the wal-index must be mapped at this point. */
assert( pWal->nWiData>0 && pWal->apWiData[0] );
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