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| author | Johannes Berg <johannes.berg@intel.com> | 2023-11-24 17:25:25 +0100 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2023-11-27 11:24:50 +0100 |
| commit | f4acfcd4deb158b96595250cc332901b282d15b0 (patch) | |
| tree | bc06b650955d9bbc41bd889f8f497ecb92e1416b /fs/debugfs/inode.c | |
| parent | 0ed04a1847a10297595ac24dc7d46b35fb35f90a (diff) | |
| download | linux-stable-f4acfcd4deb158b96595250cc332901b282d15b0.tar.gz linux-stable-f4acfcd4deb158b96595250cc332901b282d15b0.tar.bz2 linux-stable-f4acfcd4deb158b96595250cc332901b282d15b0.zip | |
debugfs: annotate debugfs handlers vs. removal with lockdep
When you take a lock in a debugfs handler but also try
to remove the debugfs file under that lock, things can
deadlock since the removal has to wait for all users
to finish.
Add lockdep annotations in debugfs_file_get()/_put()
to catch such issues.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'fs/debugfs/inode.c')
| -rw-r--r-- | fs/debugfs/inode.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index dcde4199a625..80f4f000dcc1 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -241,6 +241,14 @@ static void debugfs_release_dentry(struct dentry *dentry) if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) return; + /* check it wasn't a dir (no fsdata) or automount (no real_fops) */ + if (fsd && fsd->real_fops) { +#ifdef CONFIG_LOCKDEP + lockdep_unregister_key(&fsd->key); + kfree(fsd->lock_name); +#endif + } + kfree(fsd); } @@ -744,6 +752,10 @@ static void __debugfs_file_removed(struct dentry *dentry) fsd = READ_ONCE(dentry->d_fsdata); if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) return; + + lock_map_acquire(&fsd->lockdep_map); + lock_map_release(&fsd->lockdep_map); + if (!refcount_dec_and_test(&fsd->active_users)) wait_for_completion(&fsd->active_users_drained); } |