6.12-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 59f37036bb7ab3d554c24abc856aabca01126414 ]
At btrfs_scan_root() we are accessing the inode's root (and fs_info) in a call to btrfs_fs_closing() after we have scheduled the inode for a delayed iput, and that can result in a use-after-free on the inode in case the cleaner kthread does the iput before we dereference the inode in the call to btrfs_fs_closing().
Fix this by using the fs_info stored already in a local variable instead of doing inode->root->fs_info.
Fixes: 102044384056 ("btrfs: make the extent map shrinker run asynchronously as a work queue job") CC: stable@vger.kernel.org # 6.13+ Tested-by: Ivan Shapovalov intelfx@intelfx.name Link: https://lore.kernel.org/linux-btrfs/0414d690ac5680d0d77dfc930606cdc36e42e12f... Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/extent_map.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 93043edc8ff93..36af9aa9aab13 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -1250,6 +1250,7 @@ static struct btrfs_inode *find_first_inode_to_shrink(struct btrfs_root *root,
static long btrfs_scan_root(struct btrfs_root *root, struct btrfs_em_shrink_ctx *ctx) { + struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_inode *inode; long nr_dropped = 0; u64 min_ino = ctx->last_ino + 1; @@ -1264,7 +1265,7 @@ static long btrfs_scan_root(struct btrfs_root *root, struct btrfs_em_shrink_ctx iput(&inode->vfs_inode);
if (ctx->scanned >= ctx->nr_to_scan || - btrfs_fs_closing(inode->root->fs_info)) + btrfs_fs_closing(fs_info)) break;
cond_resched();