From: Sebastian Andrzej Siewior Date: Wed, 9 Mar 2022 22:13:45 +0000 (+0100) Subject: xdp: xdp_mem_allocator can be NULL in trace_mem_connect(). X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e0ae713023a9d09d6e1b454bdc8e8c1dd32c586e;p=linux.git xdp: xdp_mem_allocator can be NULL in trace_mem_connect(). Since the commit mentioned below __xdp_reg_mem_model() can return a NULL pointer. This pointer is dereferenced in trace_mem_connect() which leads to segfault. The trace points (mem_connect + mem_disconnect) were put in place to pair connect/disconnect using the IDs. The ID is only assigned if __xdp_reg_mem_model() does not return NULL. That connect trace point is of no use if there is no ID. Skip that connect trace point if xdp_alloc is NULL. [ Toke Høiland-Jørgensen delivered the reasoning for skipping the trace point ] Fixes: 4a48ef70b93b8 ("xdp: Allow registering memory model without rxq reference") Signed-off-by: Sebastian Andrzej Siewior Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/YikmmXsffE+QajTB@linutronix.de Signed-off-by: Jakub Kicinski --- diff --git a/net/core/xdp.c b/net/core/xdp.c index 7aba355049862..73fae16264e10 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -357,7 +357,8 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, if (IS_ERR(xdp_alloc)) return PTR_ERR(xdp_alloc); - trace_mem_connect(xdp_alloc, xdp_rxq); + if (trace_mem_connect_enabled() && xdp_alloc) + trace_mem_connect(xdp_alloc, xdp_rxq); return 0; }