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| author | David Howells <dhowells@redhat.com> | 2026-06-22 10:08:52 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-07-01 15:26:21 +0200 |
| commit | 55e841836c6f4646490f7b0347192b7a92d431ba (patch) | |
| tree | 2595bc7e780151d3d2c7487ba0159dd8646b5bb3 /fs | |
| parent | fc10c0ecf06f2981af5d04357612b00051e03e9e (diff) | |
| download | linux-55e841836c6f4646490f7b0347192b7a92d431ba.tar.gz linux-55e841836c6f4646490f7b0347192b7a92d431ba.zip | |
afs: Fix lack of locking around modifications of net->cells_dyn_ino
Fix the lack of locking around modifications of net->cells_dyn_ino by
taking net->cells_lock exclusively. This also requires to cell to be
removed from net->cells_dyn_ino in afs_destroy_cell_work() rather than in
afs_cell_destroy() as the latter runs in RCU cleanup context and sleeping
locks cannot be taken there.
Fixes: 1d0b929fc070 ("afs: Change dynroot to create contents on demand")
Closes: https://sashiko.dev/#/patchset/20260618074903.2374756-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260622090856.2746629-19-dhowells@redhat.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/afs/cell.c | 8 | ||||
| -rw-r--r-- | fs/afs/dynroot.c | 2 |
2 files changed, 8 insertions, 2 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c index fbb8a43aa7cd..9d8937ae24e2 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -205,8 +205,10 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, cell->dns_source = vllist->source; cell->dns_status = vllist->status; smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */ + down_write(&net->cells_lock); ret = idr_alloc_cyclic(&net->cells_dyn_ino, cell, 2, INT_MAX / 2, GFP_KERNEL); + up_write(&net->cells_lock); if (ret < 0) goto error; atomic_inc(&net->cells_outstanding); @@ -579,7 +581,6 @@ static void afs_cell_destroy(struct rcu_head *rcu) afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers)); afs_unuse_cell(cell->alias_of, afs_cell_trace_unuse_alias); key_put(cell->anonymous_key); - idr_remove(&net->cells_dyn_ino, cell->dynroot_ino); kfree(cell->name - 1); kfree(cell); @@ -594,6 +595,11 @@ static void afs_destroy_cell_work(struct work_struct *work) afs_see_cell(cell, afs_cell_trace_destroy); timer_delete_sync(&cell->management_timer); cancel_work_sync(&cell->manager); + + down_write(&cell->net->cells_lock); + idr_remove(&cell->net->cells_dyn_ino, cell->dynroot_ino); + up_write(&cell->net->cells_lock); + call_rcu(&cell->rcu, afs_cell_destroy); } diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c index 1d5e33bc7502..6e3c8c691ba9 100644 --- a/fs/afs/dynroot.c +++ b/fs/afs/dynroot.c @@ -278,7 +278,7 @@ static struct dentry *afs_lookup_atcell(struct inode *dir, struct dentry *dentry } /* - * Transcribe the cell database into readdir content under the RCU read lock. + * Transcribe the cell database into readdir content under net->cells_lock. * Each cell produces two entries, one prefixed with a dot and one not. */ static int afs_dynroot_readdir_cells(struct afs_net *net, struct dir_context *ctx) |