mirrors/sqlite
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix a race condition that can lead to deadlock in the memdb VFS if one

Browse Source 
thread is trying to open an existing database at the same moment that
another thread that is the only prior user of that database is trying to
close it.

FossilOrigin-Name: b635375dbe22bd31c437ca574eb0c014c0b045de6cc0816c32d2ceceff9191fb
This commit is contained in:
drh 2021-05-12 15:39:02 +00:00
parent 85ffcae177
commit 52d1407891
3 changed files with 26 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
manifest
View File

@ -1,5 +1,5 @@
C Add\sthe\snew\sthreadtest5\stest\sprogram\sfor\sstressing\smultiple\sdatabase\nconnections\sin\sthe\ssame\sprocess\shammering\son\sa\ssingle\sdatabase.\nPrimarily\sdesigned\sto\stest\smemdb,\sbut\sworks\son\sany\sdatabase.
D 2021-05-12T14:17:20.226
C Fix\sa\srace\scondition\sthat\scan\slead\sto\sdeadlock\sin\sthe\smemdb\sVFS\sif\sone\nthread\sis\strying\sto\sopen\san\sexisting\sdatabase\sat\sthe\ssame\smoment\sthat\nanother\sthread\sthat\sis\sthe\sonly\sprior\suser\sof\sthat\sdatabase\sis\strying\sto\nclose\sit.
D 2021-05-12T15:39:02.959
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@ -514,7 +514,7 @@ F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
F src/mem2.c b93b8762ab999a29ae7751532dadf0a1ac78040308a5fb1d17fcc365171d67eb
F src/mem3.c 30301196cace2a085cbedee1326a49f4b26deff0af68774ca82c1f7c06fda4f6
F src/mem5.c 9bf955937b07f8c32541c8a9991f33ce3173d944
F src/memdb.c 0c95e0299cc81e19d8695d2e7b81c338a5e77d083aa7849643eafcc2a3b1115a
F src/memdb.c 41acf2b1a80a20b38a05f03711564b51c67e6dc376cc3f6b829ae644be25ad93
F src/memjournal.c 431c70a111223a8a6e2e7e9f014afc6c88d818d357d866afc563195f2277d50e
F src/msvc.h 3a15918220367a8876be3fa4f2abe423a861491e84b864fb2b7426bf022a28f8
F src/mutex.c 5e3409715552348732e97b9194abe92fdfcd934cfb681df4ba0ab87ac6c18d25
@ -1463,7 +1463,7 @@ F test/threadtest1.c 6029d9c5567db28e6dc908a0c63099c3ba6c383b
F test/threadtest2.c a70a8e94bef23339d34226eb9521015ef99f4df8
F test/threadtest3.c e63013af10cf236c7610eb06d33bde08c861806dc64be811940ff4d9ddd34a4f
F test/threadtest4.c c1e67136ceb6c7ec8184e56ac61db28f96bd2925
F test/threadtest5.c 9b4d782c58d8915d7e955ff8051f3d03628bda0d33b82971ea8c0f2f2808c421 w test/memdb-threads-1.c
F test/threadtest5.c 9b4d782c58d8915d7e955ff8051f3d03628bda0d33b82971ea8c0f2f2808c421
F test/time-wordcount.sh 8e0b0f8109367827ad5d58f5cc849705731e4b90
F test/tkt-02a8e81d44.test 6c80d9c7514e2a42d4918bf87bf6bc54f379110c
F test/tkt-18458b1a.test 6a62cb1ee50fa3c620da59e3a6f531eb38fceaf7e2166203816b724524e6f1d6
@ -1913,7 +1913,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P 533fffc4a39b01c3aba75bd3271fd6ccd9516d9681ed04adbe19bd7de03f4c16
R 4fefc92ffd76e6c05a1532a9460cad0d
P 8db1c06958b8e1691440d4fd392648b74a1940b721852dabd315005efad520fc
R 1abbc8f5df29e63c759567b710531636
U drh
Z d3fbbeb2377b80ce42b7a7b26e8ca8a8
Z 05516c08485b60e7b77e8989ba53becd

2
manifest.uuid
View File

@ -1 +1 @@
8db1c06958b8e1691440d4fd392648b74a1940b721852dabd315005efad520fc
b635375dbe22bd31c437ca574eb0c014c0b045de6cc0816c32d2ceceff9191fb

32
src/memdb.c
View File

@ -196,29 +196,33 @@ static void memdbLeave(MemStore *p){
*/
static int memdbClose(sqlite3_file *pFile){
MemStore *p = ((MemFile*)pFile)->pStore;
memdbEnter(p);
p->nRef--;
if( p->nRef<=0 ){
if( p->mFlags & SQLITE_DESERIALIZE_FREEONCLOSE ){
sqlite3_free(p->aData);
}
if( p->zFName ){
int i;
if( p->zFName ){
int i;
#ifndef SQLITE_MUTEX_OMIT
sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
#endif
sqlite3_mutex_enter(pVfsMutex);
for(i=0; ALWAYS(i<memdb_g.nMemStore); i++){
if( memdb_g.apMemStore[i]==p ){
sqlite3_mutex_enter(pVfsMutex);
for(i=0; ALWAYS(i<memdb_g.nMemStore); i++){
if( memdb_g.apMemStore[i]==p ){
memdbEnter(p);
if( p->nRef==1 ){
memdb_g.apMemStore[i] = memdb_g.apMemStore[--memdb_g.nMemStore];
if( memdb_g.nMemStore==0 ){
sqlite3_free(memdb_g.apMemStore);
memdb_g.apMemStore = 0;
}
break;
}
break;
}
sqlite3_mutex_leave(pVfsMutex);
}
sqlite3_mutex_leave(pVfsMutex);
}else{
memdbEnter(p);
}
p->nRef--;
if( p->nRef<=0 ){
if( p->mFlags & SQLITE_DESERIALIZE_FREEONCLOSE ){
sqlite3_free(p->aData);
}
memdbLeave(p);
sqlite3_mutex_free(p->pMutex);