From: Leon Romanovsky <leonro@xxxxxxxxxx> The ib->rec.qkey field is accessed without being initialized. Clear the ib_sa_multicast struct to fix the following syzkaller error/. ===================================================== BUG: KMSAN: uninit-value in cma_set_qkey drivers/infiniband/core/cma.c:510 [inline] BUG: KMSAN: uninit-value in cma_make_mc_event+0xb73/0xe00 drivers/infiniband/core/cma.c:4570 cma_set_qkey drivers/infiniband/core/cma.c:510 [inline] cma_make_mc_event+0xb73/0xe00 drivers/infiniband/core/cma.c:4570 cma_iboe_join_multicast drivers/infiniband/core/cma.c:4782 [inline] rdma_join_multicast+0x2b83/0x30a0 drivers/infiniband/core/cma.c:4814 ucma_process_join+0xa76/0xf60 drivers/infiniband/core/ucma.c:1479 ucma_join_multicast+0x1e3/0x250 drivers/infiniband/core/ucma.c:1546 ucma_write+0x639/0x6d0 drivers/infiniband/core/ucma.c:1732 vfs_write+0x8ce/0x2030 fs/read_write.c:588 ksys_write+0x28c/0x520 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __ia32_sys_write+0xdb/0x120 fs/read_write.c:652 do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline] __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Local variable ib.i created at: cma_iboe_join_multicast drivers/infiniband/core/cma.c:4737 [inline] rdma_join_multicast+0x586/0x30a0 drivers/infiniband/core/cma.c:4814 ucma_process_join+0xa76/0xf60 drivers/infiniband/core/ucma.c:1479 CPU: 0 PID: 29874 Comm: syz-executor.3 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ===================================================== Fixes: b5de0c60cc30 ("RDMA/cma: Fix use after free race in roce multicast join") Reported-by: syzbot+8fcbb77276d43cc8b693@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx> --- drivers/infiniband/core/cma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 69c9a12dd14e..9c53e1e7de50 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -4737,7 +4737,7 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv, int err = 0; struct sockaddr *addr = (struct sockaddr *)&mc->addr; struct net_device *ndev = NULL; - struct ib_sa_multicast ib; + struct ib_sa_multicast ib = {}; enum ib_gid_type gid_type; bool send_only; -- 2.33.1