ShuriZma
/
xemu
mirror of https://github.com/xemu-project/xemu.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

multifd: Fix a race on reading MultiFDPages_t.block 

In multifd_queue_page() MultiFDPages_t.block is checked twice.
Between the two checks, MultiFDPages_t.block may be reset to NULL
by multifd thread. This lead to the 2nd check always true then a
redundant page submitted to multifd thread again.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Zhenzhong Duan 2022-10-17 15:53:50 +08:00 committed by Juan Quintela
parent 6720c2b327
commit ddbe628c97
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
migration/multifd.c
View File

@ -442,6 +442,7 @@ static int multifd_send_pages(QEMUFile *f)
int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset) int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset)
{ {
MultiFDPages_t *pages = multifd_send_state->pages; MultiFDPages_t *pages = multifd_send_state->pages;
bool changed = false;
if (!pages->block) { if (!pages->block) {
pages->block = block; pages->block = block;
@ -454,13 +455,15 @@ int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset)
if (pages->num < pages->allocated) { if (pages->num < pages->allocated) {
return 1; return 1;
} }
} else {
changed = true;
} }
if (multifd_send_pages(f) < 0) { if (multifd_send_pages(f) < 0) {
return -1; return -1;
} }
if (pages->block != block) { if (changed) {
return multifd_queue_page(f, block, offset); return multifd_queue_page(f, block, offset);
} }