From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org> To: tarantool-patches@dev.tarantool.org, korablev@tarantool.org, tsafin@tarantool.org, alyapunov@tarantool.org, gorcunov@gmail.com Subject: [Tarantool-patches] [PATCH 05/10] sql: make BtCursor's memory aligned Date: Thu, 21 May 2020 22:37:28 +0200 [thread overview] Message-ID: <7bdb9ea8c65f01e3ca1f0cc70a20e9e60fd207e1.1590093222.git.v.shpilevoy@tarantool.org> (raw) In-Reply-To: <cover.1590093222.git.v.shpilevoy@tarantool.org> Vdbe at runtime allocates VdbeCursor structure using allocateCursor() function. Inside there is a pointer at BtCursor structure. To make the allocation faster and improve cache locality, both cursors are allocated in one memory block + some extra memory for uint32_t array, where BtCursor followed VdbeCursor and the array without any padding: VdbeCursor + uint32_t * N + BtCursor The problem is that BtCursor needs 8 byte alignment. When it followed VdbeCursor (aligned by 8) + some uint32_t values, its actual alignment could become 4 bytes. That led to a crash when alignment sanitizer is enabled in clang. The patch makes BtCursor offset aligned by 8 bytes. Part of #4609 --- src/box/sql/vdbe.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c index 724bc188b..7a42602a2 100644 --- a/src/box/sql/vdbe.c +++ b/src/box/sql/vdbe.c @@ -234,10 +234,9 @@ allocateCursor( */ Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem; - int nByte; VdbeCursor *pCx = 0; - nByte = - ROUND8(sizeof(VdbeCursor)) + sizeof(u32)*nField + + int bt_offset = ROUND8(sizeof(VdbeCursor) + sizeof(uint32_t) * nField); + int nByte = bt_offset + (eCurType==CURTYPE_TARANTOOL ? ROUND8(sizeof(BtCursor)) : 0); assert(iCur>=0 && iCur<p->nCursor); @@ -251,8 +250,7 @@ allocateCursor( pCx->eCurType = eCurType; pCx->nField = nField; if (eCurType==CURTYPE_TARANTOOL) { - pCx->uc.pCursor = (BtCursor*) - &pMem->z[ROUND8(sizeof(VdbeCursor))+sizeof(u32)*nField]; + pCx->uc.pCursor = (BtCursor*)&pMem->z[bt_offset]; sqlCursorZero(pCx->uc.pCursor); } } -- 2.21.1 (Apple Git-122.3)
next prev parent reply other threads:[~2020-05-21 20:37 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-21 20:37 [Tarantool-patches] [PATCH 00/10] Sanitize unaligned access Vladislav Shpilevoy 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 01/10] small: sanitized rlist and new region API Vladislav Shpilevoy 2020-06-08 12:17 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 10/10] xrow: use unaligned store operation in xrow_to_iovec() Vladislav Shpilevoy 2020-06-08 12:26 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 02/10] cmake: ignore warnings on alignof() and offsetof() Vladislav Shpilevoy 2020-06-08 12:52 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 03/10] cmake: add option ENABLE_UB_SANITIZER Vladislav Shpilevoy 2020-06-08 12:53 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 04/10] crc32: disable align sanitizer Vladislav Shpilevoy 2020-06-08 13:58 ` Cyrill Gorcunov 2020-05-21 20:37 ` Vladislav Shpilevoy [this message] 2020-06-08 13:58 ` [Tarantool-patches] [PATCH 05/10] sql: make BtCursor's memory aligned Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 06/10] region: use aligned allocations where necessary Vladislav Shpilevoy 2020-06-08 14:00 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 07/10] vinyl: align statements and bps tree extents Vladislav Shpilevoy 2020-06-08 14:02 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 08/10] tuple: use unaligned store-load for field map Vladislav Shpilevoy 2020-06-08 14:04 ` Cyrill Gorcunov 2020-05-21 20:37 ` [Tarantool-patches] [PATCH 09/10] port: make port_c_entry not PACKED Vladislav Shpilevoy 2020-06-08 14:04 ` Cyrill Gorcunov 2020-05-21 22:25 ` [Tarantool-patches] [PATCH 00/10] Sanitize unaligned access Sergey Bronnikov 2020-05-27 23:33 ` Vladislav Shpilevoy
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