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Kernel/FS: Fix check-then-act concurrency bug in FileSystem/Inode

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When the FileSystem does a sync, it gathers up all the inodes with
dirty metadata into a vector. The inode mutex is not held while
checking the inode dirty bit, which can lead to a kernel panic
due to concurrent inode modifications.

Fixes: #21796
This commit is contained in:
Blake Smith 2023-11-19 19:15:37 -06:00 • committed by Andreas Kling
parent 2372584b18
commit e346331424
2 changed files with 4 additions and 3 deletions
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3
Kernel/FileSystem/Ext2FS/Inode.cpp
View file

@ -494,6 +494,9 @@ InodeMetadata Ext2FSInode::metadata() const
ErrorOr<void> Ext2FSInode::flush_metadata() ErrorOr<void> Ext2FSInode::flush_metadata()
{ {
MutexLocker locker(m_inode_lock); MutexLocker locker(m_inode_lock);
if (!is_metadata_dirty())
return {};
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::flush_metadata(): Flushing inode", identifier()); dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::flush_metadata(): Flushing inode", identifier());
TRY(fs().write_ext2_inode(index(), m_raw_inode)); TRY(fs().write_ext2_inode(index(), m_raw_inode));
if (is_directory()) { if (is_directory()) {

4
Kernel/FileSystem/Inode.cpp
View file

@ -39,15 +39,13 @@ void Inode::sync_all()
}); });
for (auto& inode : inodes) { for (auto& inode : inodes) {
VERIFY(inode->is_metadata_dirty());
(void)inode->flush_metadata(); (void)inode->flush_metadata();
} }
} }
void Inode::sync() void Inode::sync()
{ {
if (is_metadata_dirty()) (void)flush_metadata();
(void)flush_metadata();
auto result = fs().flush_writes(); auto result = fs().flush_writes();
if (result.is_error()) { if (result.is_error()) {
// TODO: Figure out how to propagate error to a higher function. // TODO: Figure out how to propagate error to a higher function.