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Fix concurrent mprotect/munmap causing conflict chunk and vma

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Hui, Chunyang 2023-10-25 06:39:54 +00:00 committed by volcano
parent 99c1f92ddf
commit 8759a57902
1 changed files with 26 additions and 3 deletions
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29
src/libos/src/vm/vm_manager.rs
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@ -249,16 +249,18 @@ impl VMManager {
.chunk_manager_mut() .chunk_manager_mut()
.munmap_range(munmap_range); .munmap_range(munmap_range);
} }
ChunkType::SingleVMA(_) => { ChunkType::SingleVMA(vma) => {
// Single VMA Chunk could be updated during the release of internal manager lock. Get overlapping chunk again. // Single VMA Chunk could be updated during the release of internal manager lock. Get overlapping chunk again.
// This is done here because we don't want to acquire the big internal manager lock as soon as entering this function. // This is done here because we don't want to acquire the big internal manager lock as soon as entering this function.
let mut internal_manager = self.internal(); let mut internal_manager = self.internal();
let overlapping_chunk = { let overlapping_chunk = if chunk.range() != vma.lock().unwrap().range() {
let process_mem_chunks = current.vm().mem_chunks().read().unwrap(); let process_mem_chunks = current.vm().mem_chunks().read().unwrap();
process_mem_chunks process_mem_chunks
.iter() .iter()
.find(|&chunk| chunk.range().intersect(&munmap_range).is_some()) .find(|&chunk| chunk.range().intersect(&munmap_range).is_some())
.map(|chunk| chunk.clone()) .map(|chunk| chunk.clone())
} else {
Some(chunk)
}; };
if let Some(overlapping_chunk) = overlapping_chunk { if let Some(overlapping_chunk) = overlapping_chunk {
return internal_manager.munmap_chunk( return internal_manager.munmap_chunk(
@ -313,8 +315,25 @@ impl VMManager {
.chunk_manager_mut() .chunk_manager_mut()
.mprotect(addr, size, perms); .mprotect(addr, size, perms);
} }
ChunkType::SingleVMA(_) => { ChunkType::SingleVMA(vma) => {
let mut internal_manager = self.internal(); let mut internal_manager = self.internal();
// There are rare cases that mutliple threads do mprotect or munmap for the same single-vma chunk
// but for different ranges and the cloned chunk is outdated when acquiring the InternalVMManger lock here.
// In this case, we search for the chunk again.
let chunk = if chunk.range() != vma.lock().unwrap().range() {
let current = current!();
let process_mem_chunks = current.vm().mem_chunks().read().unwrap();
let chunk = process_mem_chunks
.iter()
.find(|&chunk| chunk.range().is_superset_of(&protect_range));
if chunk.is_none() {
return_errno!(ENOMEM, "invalid mprotect range");
}
chunk.unwrap().clone()
} else {
chunk
};
return internal_manager.mprotect_single_vma_chunk(&chunk, protect_range, perms); return internal_manager.mprotect_single_vma_chunk(&chunk, protect_range, perms);
} }
} }
@ -386,6 +405,10 @@ impl VMManager {
.msync_by_range(&sync_range); .msync_by_range(&sync_range);
} }
ChunkType::SingleVMA(vma) => { ChunkType::SingleVMA(vma) => {
// Note: There are rare cases that mutliple threads do mprotect or munmap for the same single-vma chunk
// but for different ranges and the cloned chunk is outdated when the code reaches here.
// It is fine here because this function doesn't modify the global chunk list and only operates on the vma
// which is updated realtimely.
let vma = vma.lock().unwrap(); let vma = vma.lock().unwrap();
vma.flush_backed_file(); vma.flush_backed_file();
} }