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kernel/vm: Fix double-read-lock in user_set_memory_swappable.

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lock_memory_etc also acquires the address space read lock.
So, just perform that step first and separately from the loop.

Discovered by the RW_LOCK_DEBUG assertions.
This commit is contained in:
Augustin Cavalier
2025-10-17 15:56:56 -04:00
parent c02707824b
commit 89f76d7509
1 changed files with 11 additions and 9 deletions
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src/system/kernel/vm/vm.cpp
+11 -9
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@@ -6701,8 +6701,13 @@ user_set_memory_swappable(const void* _address, size_t size, bool swappable)
const addr_t endAddress = address + size;
status_t error = lock_memory_etc(B_CURRENT_TEAM,
(void*)address, endAddress - address, 0);
if (error != B_OK)
return error;
AddressSpaceReadLocker addressSpaceLocker;
status_t error = addressSpaceLocker.SetTo(team_get_current_team_id());
error = addressSpaceLocker.SetTo(team_get_current_team_id());
if (error != B_OK)
return error;
VMAddressSpace* addressSpace = addressSpaceLocker.AddressSpace();
@@ -6721,12 +6726,6 @@ user_set_memory_swappable(const void* _address, size_t size, bool swappable)
const addr_t areaEnd = std::min(endAddress, area->Base() + area->Size());
nextAddress = areaEnd;
error = lock_memory_etc(addressSpace->ID(), (void*)areaStart, areaEnd - areaStart, 0);
if (error != B_OK) {
// We don't need to unset or reset things on failure.
break;
}
VMCacheChainLocker cacheChainLocker(vm_area_get_locked_cache(area));
VMAnonymousCache* anonCache = NULL;
if (dynamic_cast<VMAnonymousNoSwapCache*>(area->cache) != NULL) {
@@ -6740,12 +6739,15 @@ user_set_memory_swappable(const void* _address, size_t size, bool swappable)
}
cacheChainLocker.Unlock();
unlock_memory_etc(addressSpace->ID(), (void*)areaStart, areaEnd - areaStart, 0);
if (error != B_OK)
break;
}
addressSpaceLocker.Unlock();
unlock_memory_etc(B_CURRENT_TEAM,
(void*)address, endAddress - address, 0);
return error;
#else
// No swap support? Nothing to do.