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| author | Shardul Bankar <shardul.b@mpiricsoftware.com> | 2025-12-29 23:49:38 +0300 |
|---|---|---|
| committer | Viacheslav Dubeyko <slava@dubeyko.com> | 2026-01-06 23:40:49 +0300 |
| commit | d8a73cc46c8462a969a7516131feb3096f4c49d3 (patch) | |
| tree | c7a478a4d7bd5cc4841ef1df42aec823f223a440 | |
| parent | b226804532a875c10276168dc55ce752944096bd (diff) | |
| download | linux-d8a73cc46c8462a969a7516131feb3096f4c49d3.tar.xz | |
hfsplus: return error when node already exists in hfs_bnode_create
When hfs_bnode_create() finds that a node is already hashed (which should
not happen in normal operation), it currently returns the existing node
without incrementing its reference count. This causes a reference count
inconsistency that leads to a kernel panic when the node is later freed
in hfs_bnode_put():
kernel BUG at fs/hfsplus/bnode.c:676!
BUG_ON(!atomic_read(&node->refcnt))
This scenario can occur when hfs_bmap_alloc() attempts to allocate a node
that is already in use (e.g., when node 0's bitmap bit is incorrectly
unset), or due to filesystem corruption.
Returning an existing node from a create path is not normal operation.
Fix this by returning ERR_PTR(-EEXIST) instead of the node when it's
already hashed. This properly signals the error condition to callers,
which already check for IS_ERR() return values.
Reported-by: syzbot+1c8ff72d0cd8a50dfeaa@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=1c8ff72d0cd8a50dfeaa
Link: https://lore.kernel.org/all/784415834694f39902088fa8946850fc1779a318.camel@ibm.com/
Fixes: 634725a92938 ("[PATCH] hfs: cleanup HFS+ prints")
Signed-off-by: Shardul Bankar <shardul.b@mpiricsoftware.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20251229204938.1907089-1-shardul.b@mpiricsoftware.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
| -rw-r--r-- | fs/hfsplus/bnode.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/hfsplus/bnode.c b/fs/hfsplus/bnode.c index 191661af9677..250a226336ea 100644 --- a/fs/hfsplus/bnode.c +++ b/fs/hfsplus/bnode.c @@ -629,7 +629,7 @@ struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num) if (node) { pr_crit("new node %u already hashed?\n", num); WARN_ON(1); - return node; + return ERR_PTR(-EEXIST); } node = __hfs_bnode_create(tree, num); if (!node) |