From 1bb9e731e17b79f5b1c6713159812adfcf4f6495 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 30 Mar 2018 13:53:33 -0400 Subject: [PATCH] Improve out-of-memory error reports by including memory context name. Add the target context's name to the errdetail field of "out of memory" errors in mcxt.c. Per discussion, this seems likely to be useful to help narrow down the cause of a reported failure, and it costs little. Also, now that context names are required to be compile-time constants in all cases, there's little reason to be concerned about security issues from exposing these names to users. (Because of such concerns, we are *not* including the context "ident" field.) In passing, add unlikely() markers to the allocation-failed tests, just to be sure the compiler is on the right page about that. Also, in palloc and friends, copy CurrentMemoryContext into a local variable, as that's almost surely cheaper to reference than a global. Discussion: https://postgr.es/m/1099.1522285628@sss.pgh.pa.us --- src/backend/utils/mmgr/mcxt.c | 90 +++++++++++++++++++++-------------- 1 file changed, 55 insertions(+), 35 deletions(-) diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c index 6cda41481f..ebe0342f18 100644 --- a/src/backend/utils/mmgr/mcxt.c +++ b/src/backend/utils/mmgr/mcxt.c @@ -781,13 +781,21 @@ MemoryContextAlloc(MemoryContext context, Size size) context->isReset = false; ret = context->methods->alloc(context, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); + + /* + * Here, and elsewhere in this module, we show the target context's + * "name" but not its "ident" (if any) in user-visible error messages. + * The "ident" string might contain security-sensitive data, such as + * values in SQL commands. + */ ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } VALGRIND_MEMPOOL_ALLOC(context, ret, size); @@ -816,13 +824,14 @@ MemoryContextAllocZero(MemoryContext context, Size size) context->isReset = false; ret = context->methods->alloc(context, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } VALGRIND_MEMPOOL_ALLOC(context, ret, size); @@ -853,13 +862,14 @@ MemoryContextAllocZeroAligned(MemoryContext context, Size size) context->isReset = false; ret = context->methods->alloc(context, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } VALGRIND_MEMPOOL_ALLOC(context, ret, size); @@ -888,7 +898,7 @@ MemoryContextAllocExtended(MemoryContext context, Size size, int flags) context->isReset = false; ret = context->methods->alloc(context, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { if ((flags & MCXT_ALLOC_NO_OOM) == 0) { @@ -896,7 +906,8 @@ MemoryContextAllocExtended(MemoryContext context, Size size, int flags) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } return NULL; } @@ -914,26 +925,28 @@ palloc(Size size) { /* duplicates MemoryContextAlloc to avoid increased overhead */ void *ret; + MemoryContext context = CurrentMemoryContext; - AssertArg(MemoryContextIsValid(CurrentMemoryContext)); - AssertNotInCriticalSection(CurrentMemoryContext); + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); if (!AllocSizeIsValid(size)) elog(ERROR, "invalid memory alloc request size %zu", size); - CurrentMemoryContext->isReset = false; + context->isReset = false; - ret = CurrentMemoryContext->methods->alloc(CurrentMemoryContext, size); - if (ret == NULL) + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } - VALGRIND_MEMPOOL_ALLOC(CurrentMemoryContext, ret, size); + VALGRIND_MEMPOOL_ALLOC(context, ret, size); return ret; } @@ -943,26 +956,28 @@ palloc0(Size size) { /* duplicates MemoryContextAllocZero to avoid increased overhead */ void *ret; + MemoryContext context = CurrentMemoryContext; - AssertArg(MemoryContextIsValid(CurrentMemoryContext)); - AssertNotInCriticalSection(CurrentMemoryContext); + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); if (!AllocSizeIsValid(size)) elog(ERROR, "invalid memory alloc request size %zu", size); - CurrentMemoryContext->isReset = false; + context->isReset = false; - ret = CurrentMemoryContext->methods->alloc(CurrentMemoryContext, size); - if (ret == NULL) + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } - VALGRIND_MEMPOOL_ALLOC(CurrentMemoryContext, ret, size); + VALGRIND_MEMPOOL_ALLOC(context, ret, size); MemSetAligned(ret, 0, size); @@ -974,18 +989,19 @@ palloc_extended(Size size, int flags) { /* duplicates MemoryContextAllocExtended to avoid increased overhead */ void *ret; + MemoryContext context = CurrentMemoryContext; - AssertArg(MemoryContextIsValid(CurrentMemoryContext)); - AssertNotInCriticalSection(CurrentMemoryContext); + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) || ((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size))) elog(ERROR, "invalid memory alloc request size %zu", size); - CurrentMemoryContext->isReset = false; + context->isReset = false; - ret = CurrentMemoryContext->methods->alloc(CurrentMemoryContext, size); - if (ret == NULL) + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) { if ((flags & MCXT_ALLOC_NO_OOM) == 0) { @@ -993,12 +1009,13 @@ palloc_extended(Size size, int flags) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } return NULL; } - VALGRIND_MEMPOOL_ALLOC(CurrentMemoryContext, ret, size); + VALGRIND_MEMPOOL_ALLOC(context, ret, size); if ((flags & MCXT_ALLOC_ZERO) != 0) MemSetAligned(ret, 0, size); @@ -1038,13 +1055,14 @@ repalloc(void *pointer, Size size) Assert(!context->isReset); ret = context->methods->realloc(context, pointer, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size); @@ -1072,13 +1090,14 @@ MemoryContextAllocHuge(MemoryContext context, Size size) context->isReset = false; ret = context->methods->alloc(context, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } VALGRIND_MEMPOOL_ALLOC(context, ret, size); @@ -1106,13 +1125,14 @@ repalloc_huge(void *pointer, Size size) Assert(!context->isReset); ret = context->methods->realloc(context, pointer, size); - if (ret == NULL) + if (unlikely(ret == NULL)) { MemoryContextStats(TopMemoryContext); ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed on request of size %zu.", size))); + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); } VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size); -- 2.40.0