From: Rafael Mendonca rafaelmendsr@gmail.com
commit 996d3efeb091c503afd3ee6b5e20eabf446fd955 upstream.
If the CPU mask allocation for a node fails, then the memory allocated for the 'io_wqe' struct of the current node doesn't get freed on the error handling path, since it has not yet been added to the 'wqes' array.
This was spotted when fuzzing v6.1-rc1 with Syzkaller: BUG: memory leak unreferenced object 0xffff8880093d5000 (size 1024): comm "syz-executor.2", pid 7701, jiffies 4295048595 (age 13.900s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000cb463369>] __kmem_cache_alloc_node+0x18e/0x720 [<00000000147a3f9c>] kmalloc_node_trace+0x2a/0x130 [<000000004e107011>] io_wq_create+0x7b9/0xdc0 [<00000000c38b2018>] io_uring_alloc_task_context+0x31e/0x59d [<00000000867399da>] __io_uring_add_tctx_node.cold+0x19/0x1ba [<000000007e0e7a79>] io_uring_setup.cold+0x1b80/0x1dce [<00000000b545e9f6>] __x64_sys_io_uring_setup+0x5d/0x80 [<000000008a8a7508>] do_syscall_64+0x5d/0x90 [<000000004ac08bec>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: 0e03496d1967 ("io-wq: use private CPU mask") Cc: stable@vger.kernel.org Signed-off-by: Rafael Mendonca rafaelmendsr@gmail.com Link: https://lore.kernel.org/r/20221020014710.902201-1-rafaelmendsr@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/io-wq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -1152,10 +1152,10 @@ struct io_wq *io_wq_create(unsigned boun wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node); if (!wqe) goto err; + wq->wqes[node] = wqe; if (!alloc_cpumask_var(&wqe->cpu_mask, GFP_KERNEL)) goto err; cpumask_copy(wqe->cpu_mask, cpumask_of_node(node)); - wq->wqes[node] = wqe; wqe->node = alloc_node; wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded; wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =