From: Dominik Grzegorzek <dominik.grzegorzek@oracle.com> mainline inclusion from mainline-v6.15 commit d6ebcde6d4ecf34f8495fb30516645db3aea8993 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/ICAXLF Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- A recent patch that addressed a UAF introduced a reference count leak: the parallel_data refcount is incremented unconditionally, regardless of the return value of queue_work(). If the work item is already queued, the incremented refcount is never decremented. Fix this by checking the return value of queue_work() and decrementing the refcount when necessary. Resolves: Unreferenced object 0xffff9d9f421e3d80 (size 192): comm "cryptomgr_probe", pid 157, jiffies 4294694003 hex dump (first 32 bytes): 80 8b cf 41 9f 9d ff ff b8 97 e0 89 ff ff ff ff ...A............ d0 97 e0 89 ff ff ff ff 19 00 00 00 1f 88 23 00 ..............#. backtrace (crc 838fb36): __kmalloc_cache_noprof+0x284/0x320 padata_alloc_pd+0x20/0x1e0 padata_alloc_shell+0x3b/0xa0 0xffffffffc040a54d cryptomgr_probe+0x43/0xc0 kthread+0xf6/0x1f0 ret_from_fork+0x2f/0x50 ret_from_fork_asm+0x1a/0x30 Fixes: dd7d37ccf6b1 ("padata: avoid UAF for reorder_work") Cc: <stable@vger.kernel.org> Signed-off-by: Dominik Grzegorzek <dominik.grzegorzek@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Wang Tao <wangtao554@huawei.com> --- kernel/padata.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/padata.c b/kernel/padata.c index 071d8cad8078..93cd7704ab63 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -358,7 +358,8 @@ static void padata_reorder(struct parallel_data *pd) * To avoid UAF issue, add pd ref here, and put pd ref after reorder_work finish. */ padata_get_pd(pd); - queue_work(pinst->serial_wq, &pd->reorder_work); + if (!queue_work(pinst->serial_wq, &pd->reorder_work)) + padata_put_pd(pd); } } -- 2.34.1